Nuvera® C95A-33 N95A-21 Fuel Cell System Diagnostic Troubleshooting Manual - PDF DOWNLOAD by www.heydownloads.com

Diagnostic Troubleshooting Manual Fuel Cell System C95A-33 N95A-21

31002994 | 05/2020

NOTICE OF PROPRIETARY PROPERTY This document and the information contained in it are the proprietary property of Nuvera Fuel Cells LLC. This document is intended solely for the internal use of the recipient and may not be used outside the recipient's organization nor distributed to third parties without the express prior written consent of Nuvera Fuel Cells LLC.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Contents

Table of Contents General Information General hazards, warnings, and cautionary statements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Diagnostic troubleshooting codes DTC 1-Coolant inlet temperature out of range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Diagnose and troubleshoot DTC 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 DTC 2-Coolant inlet temperature out of range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Diagnose and troubleshoot DTC 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 DTC 3-Coolant outlet temperature out of range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Diagnose and troubleshoot DTC 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 DTC 4-Coolant outlet temperature out of range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Diagnose and troubleshoot DTC 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 DTC 5-Anode supply pressure out of range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 Diagnose and troubleshoot DTC 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 DTC 6-Anode outlet pressure out of range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Diagnose and troubleshoot DTC 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 DTC 7-Fuel cell stack current out of range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Diagnose and troubleshoot DTC 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 DTC 9-CVM loss of communication. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 Diagnose and troubleshoot DTC 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 DTC 11-High coolant inlet temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 Diagnose and troubleshoot DTC 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 DTC 12-High coolant inlet temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26 Diagnose and troubleshoot DTC 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 DTC 14-High coolant outlet temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Diagnose and troubleshoot DTC 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 DTC 15-High coolant outlet temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Diagnose and troubleshoot DTC 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 DTC 16-High coolant outlet temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Diagnose and troubleshoot DTC 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 DTC 17-High cathode inlet temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Diagnose and troubleshoot DTC 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 DTC 18-High anode outlet pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 Diagnose and troubleshoot DTC 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 DTC 19-High anode outlet pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 I

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Contents

Diagnostic troubleshooting codes Diagnose and troubleshoot DTC 19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 DTC 20-Low anode outlet pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Diagnose and troubleshoot DTC 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 DTC 21-Low anode outlet pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Diagnose and troubleshoot DTC 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 DTC 22-High cathode inlet pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Diagnose and troubleshoot DTC 22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 DTC 25-Minimum cell voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Diagnose and troubleshoot DTC 25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 DTC 26-Minimum cell voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Diagnose and troubleshoot DTC 26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 DTC 27-Minimum cell voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Diagnose and troubleshoot DTC 27. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 DTC 28-Low anode purge (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after). . . 63 Diagnose and troubleshoot DTC 28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 DTC 32-Low stack bypass airflow (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 Diagnose and troubleshoot DTC 32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 DTC 33-Low anode outlet pressure at start-up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Diagnose and troubleshoot DTC 33. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 DTC 34-Low anode supply pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 Diagnose and troubleshoot DTC 34. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 DTC 35-Minimum cell voltage at start-up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Diagnose and troubleshoot DTC 35. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 DTC 36-Low cathode air flow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 Diagnose and troubleshoot DTC 36. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 DTC 38-Minimum cell voltage at shutdown. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 Diagnose and troubleshoot DTC 38. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 DTC 40-Low cell voltage at OCV. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 Diagnose and troubleshoot DTC 40. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 DTC 41-Minimum cell voltage at shutdown. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 Diagnose and troubleshoot DTC 41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 DTC 42-High average cell voltage at shutdown. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 Diagnose and troubleshoot DTC 42. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 DTC 52-High coolant inlet temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .84 Diagnose and troubleshoot DTC 52. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 DTC 53-High coolant delta temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 Diagnose and troubleshoot DTC 53. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 II

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

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Diagnostic troubleshooting codes DTC 54-Low cathode inlet dew-point. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 Diagnose and troubleshoot DTC 54. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 DTC 55-Low cathode inlet pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Diagnose and troubleshoot DTC 55. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 DTC 62-Low anode supply pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 Diagnose and troubleshoot DTC 62. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 DTC 63-High anode supply pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 Diagnose and troubleshoot DTC 63. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 DTC 71-Not tracking humidifier bypass valve (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 Diagnose and troubleshoot DTC 71. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 DTC 72-Not tracking radiator bypass valve (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 Diagnose and troubleshoot DTC 72. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 DTC 75-Very low state of charge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .105 Diagnose and troubleshoot DTC 75. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 DTC 76-Air inlet temperature out of range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 Diagnose and troubleshoot DTC 76. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 DTC 77-High air inlet temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 Diagnose and troubleshoot DTC 77. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 DTC 78-Ultracapacitors current out of range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 Diagnose and troubleshoot DTC 78. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 DTC 79-H2 tank pressure out of range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .111 Diagnose and troubleshoot DTC 79. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 DTC 80-Low H2 tank pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 Diagnose and troubleshoot DTC 80. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 DTC 81-Low H2 tank pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114 Diagnose and troubleshoot DTC 81. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114 DTC 82-Low H2 tank pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 Diagnose and troubleshoot DTC 82. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 DTC 84-High water tank level. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 Diagnose and troubleshoot DTC 84. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 DTC 85-High water tank level. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 Diagnose and troubleshoot DTC 85. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 DTC 86-Low motor controller speed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 Diagnose and troubleshoot DTC 86. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 DTC 88-Motor controller error status. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 Diagnose and troubleshoot DTC 88. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 III

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Contents

Diagnostic troubleshooting codes DTC 89-Motor controller warning status. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120 Diagnose and troubleshoot DTC 89. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 DTC 90-DC/DC Loss of communication. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 Diagnose and troubleshoot DTC 90. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 DTC 91-DC/DC error status. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 Diagnose and troubleshoot DTC 91. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 DTC 92-DC/DC warning status. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 Diagnose and troubleshoot DTC 92. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 DTC 94-Fuel cell back current. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 Diagnose and troubleshoot DTC 94. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 DTC 95-Anode over-pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .127 Diagnose and troubleshoot DTC 95. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127 DTC 96-High state of charge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 Diagnose and troubleshoot DTC 96. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 DTC 97-System switch-off relay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130 Diagnose and troubleshoot DTC 97. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130 DTC 98-Low/High state of charge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 Diagnose and troubleshoot DTC 98. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 DTC 99-Low/High state of charge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 Diagnose and troubleshoot DTC 99. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 DTC 100-5VDC supply of VSM Faulted. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 Diagnose and troubleshoot DTC 100. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 DTC 101-12VDC supply of VSM faulted. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 Diagnose and troubleshoot DTC 101. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 DTC 102-Stand-by mode timed out. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 Diagnose and troubleshoot DTC 102. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 DTC 103-EWS loss of integrity (fuel cell systems S/N A2D1S01500R or S/N A2D2S01500R and after). 136 Diagnose and troubleshoot DTC 103. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 Tables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 Fault code quick reference. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .138 Principles of operation Nuvera® Fuel Cell System operating state flow logic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 PreStart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 Ready. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 Off. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 Anode Start. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 IV

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Principles of operation Dilution Start. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .150 Anode Purge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 Bleed Connect. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 Cathode Purge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 Run. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 Standby SoC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 Standby. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 Start button. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .153 Stop button. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 Faults. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 Parts identification and wiring diagrams Legend. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 Parts identification diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .156 Wiring diagrams (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) 158 Wiring diagrams (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after). . . . . . . . . . 167

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List of Figures Figure 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Title

Page

VSM Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 VSM Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 VSM Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 VSM Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 VSM Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Electrical connectors (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Electrical connectors (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after). . . .20 VSM Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Electrical connectors (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Electrical connectors (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after). . . .25 Electrical connectors (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Electrical connectors (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after). . . .29 VSM Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Electrical connectors (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Electrical connectors (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after). . . .34 Electrical connectors (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Electrical connectors (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after). . . .38 Electrical connectors (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Electrical connectors (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after). . . .42 VSM Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Fuel system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Fuel system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 CVM connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Heater (HTR303). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 CVM connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Heater (HTR303). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Electrical connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65 Fuel system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 Fuel system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 CVM connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Heater (HTR303). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 VI

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List of Figures Figure 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63

Title

Page

Heater (HTR303). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 Heater (HTR303). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 Heater (HTR303). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 Heater (HTR303). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 Electrical connectors (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 Electrical connectors (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after). . . .87 Electrical connectors (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 Electrical connectors (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after). . . .90 VSM Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 Electrical connectors (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 Electrical connectors (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after). . . .95 Fuel system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 Fuel system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101 VSM Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 VSM Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 VSM Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 Legend: Parts identification diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .155 Parts identification diagram (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 Parts identification diagram (fuel cell systems S/N A2D1S01500R or S/N A2D2S01500R and after). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 Sheet 1 of 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158 Sheet 2 of 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 Sheet 3 of 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 Sheet 4 of 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 Sheet 5 of 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 Sheet 6 of 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 Sheet 7 of 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164 Sheet 8 of 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165 Sheet 9 of 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166 Sheet 1 of 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 Sheet 2 of 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168 Sheet 3 of 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 Sheet 4 of 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170 VII

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Contents

List of Figures Figure 64 65 66 67 68

Title

Page

Sheet 5 of 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 Sheet 6 of 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172 Sheet 7 of 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 Sheet 8 of 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 Sheet 9 of 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175

VIII

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Contents

List of Tables Table 1 2 3 4

Title

Page

Expected resistance measurement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 Expected resistance measurement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 Alarms list. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 Activation states. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

General Information

General hazards, warnings, and cautionary statements

CAUTION Nuvera® fuel cell systems in this manual are designed for specific applications. To avoid severe damage to the fuel cell system, do not connect the fuel cell system to any device other than a lift truck or an approved service load bank. Damage from connecting the fuel cell system to an unapproved device is not covered under warranty. 1.

Read this manual and other relevant documentation in its entirety before servicing this equipment. This manual provides specific guidelines for proper servicing of the Nuvera® Fuel Cell System.

Ensure that all service technicians are trained in the proper use of these systems. Provide all service technicians with a copy of this manual for reference before servicing the system.

CAUTION There are hot surfaces, rotating parts, and hazardous electrical equipment inside the enclosure that could cause burns, cuts, and other injuries. Do not service if any covers are loose or missing. 3.

Before operation, make sure that all guards and covers are in place. Perform a daily inspection of the system to eliminate unwanted material that can hinder operation of the system or create a hazardous situation.

All maintenance should be performed by an authorized service provider or a Nuvera Fuel Cells LLC. representative. Unauthorized maintenance or repairs without proper certifications and training could result in a hazardous situation. Unauthorized maintenance or repairs may also void all warranties on the system.

Before servicing the equipment, familiarize yourself with the system and its controls.

If the fuel cell system appears unsafe to operate for any reason, shut the system down and contact your authorized local service provider.

If a hazardous situation is discovered with the fuel cell system, such as an external or internal fire or large escape of flammable gas, shut down the system IMMEDIATELY if it is safe to do so. See Emergency response procedures within the fuel cell system operating manual for more information.

Disconnecting the main power connector will remove power from the truck. However, this will not act as emergency stop or de-energize the fuel cell system.

Do not service in any hazardous (classified) area other than while refueling.

10. For indoor use only. Not rated for high humidity, wet, or rainy conditions. 11. Do not use the hydrogen fuel vessels ("tanks") past their expiration dates. The expiration dates are located on the nameplate. 1

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

General Information

General hazards, warnings, and cautionary statements (continued) 12. Do not spray or power wash fuel cell system with any liquids. 13. The fuel cell system is not rated for use below -4°F (-20° C) or above 113°F (45°C). Do not store or leave unattended in freezer.

WARNING The fuel cell system uses oxygen from the area in which it is being used. The fuel cell system should not be used in areas of tight construction with inadequate air ventilation. 14. Use only with NFPA Type E or Type CGH industrial electric trucks.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

General Information

Overview This Nuvera® Diagnostic Troubleshooting Manual is a guide to understanding and responding to diagnostic and troubleshooting codes (DTC's). DTC's are generated when the fuel cell system experiences a system error, causing a fault. DTC codes can be observed on the Nuvera Fuel Cell System Service Tool.

Service Tool 1.

MENU BAR

FUEL CELL STATE FIELD

ERROR CODES

ERROR CODE DROP-DOWN MENU

ERROR CODE DESCRIPTION

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 1-Coolant inlet temperature out of range Tripping conditions Coolant inlet temperature TT304 ˂ 0°C for more than 1 second Action Shutdown System fault indicator on HMI is red and blinking Activation states Always

Diagnose and troubleshoot DTC 1 1. Is fuel cell system being operated in freezing conditions? YES - Fuel cell system is not rated for use in freezing conditions. If operating in a freezer, move lift truck to a warmer location. NO - Proceed to Step 2. 2.

Is TT304 connector plugged? YES - Proceed to Step 3. NO - Connector will read -32.2°C in unplugged state. If this occurs, connect TT304. If DTC 1 is still triggering, proceed to Step 3.

Are one or more of DTCs 3, 5, 6, 7, 78, 79 triggering? YES - Check if V3 connector of VSM is plugged and properly wired (Item 3, Figure 1). If proper wiring is confirmed and DTC 1 still triggers, proceed to Step 4. NO - Fix wiring connection.

Is DTC 1 still triggering? YES - Check wiring between TT304 and VSM. If DTC 1 still triggers, proceed to Step 5.

Is NTC expected resistance measurement consistent with room temperature? Check NTC expected resistance measurement. See Table 1. YES - If NTC expected resistance measurement is found to be consistent with room temperature, proceed to Step 6. NO - Replace TT304. See Replacing thermocouples (TT304 and TT351) in the Nuvera® Fuel Cell System Service Manual.

NOTE: TT304 and TT351 are included in a set. If one is in need of being replaced, both must be replaced at that time.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 1-Coolant inlet temperature out of range (continued) Diagnose and troubleshoot DTC 1 (continued)

Figure 1. VSM Connectors 1.

V1 CONNECTOR

V2 CONNECTOR

V3 CONNECTOR

V4 CONNECTOR

V5 CONNECTOR

If DTC 1 still triggers, contact Nuvera for assistance.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 2-Coolant inlet temperature out of range Tripping conditions Coolant inlet temperature TT304 ˃ 100°C for more than 1 second Action Shutdown System fault indicator on HMI is red and blinking Activation states Always

Diagnose and troubleshoot DTC 2 1. Has DTC 100 triggered also? YES - VDC supply voltage to TT304 from VSM has failed causing a misreading of TT304. See DTC 100-5VDC supply of VSM Faulted or restart fuel cell system. Contact Nuvera if DTC 100 occurs frequently. NO - Proceed to Step 2. 2.

Was most recent fuel cell system shut-down due to either DTC 11 or DTC 14?

NOTE: High temperature during operation may have caused irreversible damage to fuel cell system. YES - Remove hydrogen from the fuel cell stack. See Vent hydrogen from engine plumbing lines in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 4. 3.

Has fuel cell system cooled down? YES - If fuel cell system has sufficiently cooled and DTC 2 still triggers, proceed to Step 4. NO - Allow fuel cell system to cool down, then proceed to Step 4.

Is NTC expected resistance measurement consistent with room temperature?

NOTE: Check NTC expected resistance measurement. See Table 1. YES - If NTC expected resistance measurement is found to be consistent with room temperature, proceed to Step 5. NO - Replace TT304. See Replacing thermocouples (TT304 and TT351) in the Nuvera® Fuel Cell System Service Manual. NOTE: TT304 and TT351 are included in a set. If one is in need of being replaced, both must be replaced at that time. 5.

Are any of DTC's 25, 26, 27, and 35 triggered when restarting fuel cell system? YES - Fuel cell system may need to be replaced. Contact Nuvera for assistance. NO - If any of DTC's 25, 26, 27, and 35 are not triggered, proceed to Step 6. 6

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 2-Coolant inlet temperature out of range (continued) Diagnose and troubleshoot DTC 2 (continued) 6.

If DTC 2 still triggers, contact Nuvera for assistance.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 3-Coolant outlet temperature out of range Tripping conditions Coolant outlet temperature TT351 ˂ 0°C for more than 1 second Action Shutdown System fault indicator on HMI is red and blinking Activation states Always

Diagnose and troubleshoot DTC 3 1. Is fuel cell system being operated in freezing conditions? YES - Fuel cell system is not rated for use in freezing conditions. If operating in a freezer, move lift truck to a warmer location. NO - Proceed to Step 2. 2.

Is TT351 connector plugged? YES - Proceed to Step 3. NO - Plug TT351 connector.

Are one or more of DTCs 1, 5, 6, 7, 78, 79 triggering? YES - Check if V3 connector of VSM is plugged and properly wired (Item 3, Figure 2). If proper wiring is confirmed and DTC 3 still triggers, proceed to Step 4. NO - Fix wiring connection.

Is DTC 3 still triggering? YES - Check wiring between TT351 and VSM. If DTC 3 still triggers, proceed to Step 5.

Is NTC expected resistance measurement consistent with room temperature? Check NTC expected resistance measurement. See Table 1. YES - If NTC expected resistance measurement is found to be consistent with room temperature, proceed to Step 6. NO - Replace TT351. See Replacing thermocouples (TT304 and TT351) in the Nuvera® Fuel Cell System Service Manual.

NOTE: TT304 and TT351 are included in a set. If one is in need of being replaced, both must be replaced at that time.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 3-Coolant outlet temperature out of range (continued) Diagnose and troubleshoot DTC 3 (continued)

Figure 2. VSM Connectors 1.

V1 CONNECTOR

V2 CONNECTOR

V3 CONNECTOR

V4 CONNECTOR

V5 CONNECTOR

If DTC 1 still triggers, contact Nuvera for assistance.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 4-Coolant outlet temperature out of range Tripping conditions Coolant outlet temperature TT351 ˃ 100°C for more than 1 second Action Shutdown System fault indicator on HMI is red and blinking Activation states Always

Diagnose and troubleshoot DTC 4 1. Has DTC 100 triggered also? YES - VDC supply voltage to TT351 from VSM has failed causing a misreading of TT351. See DTC 100-5VDC supply of VSM Faulted or restart fuel cell system. Contact Nuvera if DTC 100 occurs frequently. NO - Proceed to Step 2. 2.

Was most recent fuel cell system shut-down due to either DTC 11 or DTC 14?

NOTE: High temperature during operation may have caused irreversible damage to fuel-cell. YES - Remove hydrogen from the fuel cell stack. See Vent hydrogen from engine plumbing lines in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 4. 3.

Has fuel cell system cooled down? YES - If fuel cell system has sufficiently cooled and DTC 4 still triggers, proceed to Step 4. NO - Allow fuel cell system to cool down, then proceed to Step 4.

Is NTC expected resistance measurement consistent with room temperature?

NOTE: Check NTC expected resistance measurement. See Table 1. YES - If NTC expected resistance measurement is found to be consistent with room temperature, proceed to Step 5. NO - Replace TT351. See Replacing thermocouples (TT304 and TT351) in the Nuvera® Fuel Cell System Service Manual. NOTE: TT304 and TT351 are included in a set. If one is in need of being replaced, both must be replaced at that time. 5.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 4-Coolant outlet temperature out of range (continued) Diagnose and troubleshoot DTC 4 (continued) 6.

If DTC 4 still triggers, contact Nuvera for assistance.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 5-Anode supply pressure out of range Tripping conditions Anode supply pressure PT102 ˂ 50 mbara for more than 1 second Action None System fault indicator on HMI is yellow. Activation states Always

Diagnose and troubleshoot DTC 5 1. Has DTC 100 triggered also? YES - 5 VDC supply voltage to PT102 from VSM has failed causing a misreading of PT102. See DTC 100-5VDC supply of VSM Faulted or restart fuel cell system. Contact Nuvera if DTC 100 occurs frequently. NO - Proceed to Step 2. 2.

Are DTCs 20 and 21 triggering? YES - Follow instructions in DTC 20-Low anode outlet pressure and DTC 21-Low anode outlet pressure. NO - Proceed to Step 3.

Is PT102 connector plugged? YES - Proceed to Step 4. NO - Plug PT102 connector.

Are one or more of DTCs 1, 3, 6, 7, 78, 79 triggering? YES - Check V3 connector of VSM is plugged and properly wired (Item 3, Figure 3). If proper connection of wiring is confirmed and DTC 5 still triggers, proceed to Step 5. NO - Proceed to Step 5.

Is DTC 5 still triggering? YES - Check wiring between PT102 and VSM. If wiring is properly connected and DTC 5 still triggers, replace PT102. • If PT102 has been replaced and DTC 5 still triggers, proceed to Step 6.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 5-Anode supply pressure out of range (continued) Diagnose and troubleshoot DTC 5 (continued)

Figure 3. VSM Connectors 1.

V1 CONNECTOR

V2 CONNECTOR

V3 CONNECTOR

V4 CONNECTOR

V5 CONNECTOR

If DTC 5 still triggers, contact Nuvera for assistance.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 6-Anode outlet pressure out of range Tripping conditions Anode pressure PT157 ˂ 50 mbara for more than 1 second Action None System fault indicator on HMI is yellow. Activation states Always

Diagnose and troubleshoot DTC 6 1. Has DTC 100 triggered also? YES - 5 VDC supply voltage to PT157 from VSM has failed causing a misreading of PT157. See DTC 100-5VDC supply of VSM Faulted or restart fuel cell system. Contact Nuvera if DTC 100 occurs frequently. NO - Proceed to Step 2. 2.

Are DTCs 20 and 21 triggering? YES - Follow instructions in DTC 20-Low anode outlet pressure and DTC 21-Low anode outlet pressure. NO - Proceed to Step 3.

Is PT157 connector plugged? YES - Proceed to Step 4. NO - Plug PT157 connector.

Are one or more of DTCs 1, 3, 5, 7, 78, 79 triggering? YES - Check that V3 connector of VSM is plugged and properly wired (Item 3, Figure 4). If proper connection of wiring is confirmed and DTC 6 still triggers, proceed to Step 5. NO - Proceed to Step 5.

Is DTC 6 still triggering? YES - Check wiring between PT157 and VSM. If wiring is properly connected and DTC 6 still triggers, replace PT157. • If PT157 has been replaced and DTC 6 still triggers, proceed to Step 6.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 6-Anode outlet pressure out of range (continued) Diagnose and troubleshoot DTC 6 (continued)

Figure 4. VSM Connectors 1.

V1 CONNECTOR

V2 CONNECTOR

V3 CONNECTOR

V4 CONNECTOR

V5 CONNECTOR

If DTC 6 still triggers, contact Nuvera for assistance.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 7-Fuel cell stack current out of range Tripping conditions Fuel cell system current ˂ -50 Amp for more than 1 second Action Shutdown System fault indicator on HMI is red and blinking Activation states Always

Diagnose and troubleshoot DTC 7 1. Has DTC 100 triggered also? YES - 5 VDC supply voltage to current sensor from VSM has failed causing a misreading of sensor. See DTC 100-5VDC supply of VSM Faulted or restart fuel cell system. Contact Nuvera if DTC 100 occurs frequently. NO - Proceed to Step 2. 2.

Is current sensor connector plugged? YES - Proceed to Step 3. NO - Plug current sensor connector.

Are one or more of DTCs 1, 3, 5, 6, 78, 79 triggering? YES - Check that V3 connector of VSM is plugged and properly wired (Item 3, Figure 5). If proper wiring is confirmed and DTC 7 still triggers, proceed to Step 4. NO - Proceed to Step 4.

Is DTC 7 still triggering? YES - Check wiring between current sensor and VSM. If wiring is properly connected and DTC 7 still triggers, replace current sensor. • If current sensor has been replaced and DTC 7 still triggers, proceed to Step 5.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 7-Fuel cell stack current out of range (continued) Diagnose and troubleshoot DTC 7 (continued)

Figure 5. VSM Connectors 1.

V1 CONNECTOR

V2 CONNECTOR

V3 CONNECTOR

V4 CONNECTOR

V5 CONNECTOR

If DTC 7 still triggers, contact Nuvera for assistance.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 9-CVM loss of communication Tripping conditions CVM not communicating for more than 3 seconds Action Shutdown System fault indicator on HMI is red and blinking Activation states Always

Diagnose and troubleshoot DTC 9 1. Is CVM CAN and powering connector plugged? YES - Proceed to Step 2. NO - Plug CVM connector. 2.

Is power provided to CVM connector? YES - Proceed to Step 3. NO - See Figure 6 or Figure 7, and perform Step a. through Step c. below:

Check fuse F06 and contactors K06 and K03

Check wiring between CVM and DC/DC converter

Check wiring between batteries and DC/DC converter

Is CAN bus of channel 1 either faulted or loaded with a large number of errors?

NOTE: Since channel 1 has the two 120 Ω termination resistance on VSM and on HMI, 60 Ω should be read at CVM level. YES - Check if bus is properly terminated. NO - Proceed to Step 4. 4.

Is CAN bus of channel 1 either faulted or loaded with a large number of errors, again? YES - Proceed to Step 5. NO - Check wiring of all components on CAN bus of channel 1.

Is proper firmware loaded on CVM? YES - Proceed to Step 6. NO - Check CVM loaded firmware version. Update if necessary.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 9-CVM loss of communication (continued) Diagnose and troubleshoot DTC 9 (continued) 6.

Is CAN bus of channel 1 properly loaded with messages from TRICAN sensor? YES - Proceed to Step 7. NO - Replace CVM

Figure 6. Electrical connectors (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) 1.

DC-DC CONNECTOR

BATTERY WIRING

FUSES

DPS WIRING

RELAY (K14)

RELAY (K06)

FAN CONNECTOR

PUMP CONNECTOR

K01

10.

K03

11.

K04

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 9-CVM loss of communication (continued) Diagnose and troubleshoot DTC 9 (continued)

Figure 7. Electrical connectors (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) 1.

BATTERY SYSTEM

BATTERY WIRING

FAN CONNECTOR

FUSES

K01

HIGH PRESSURE WIRE HARNESS

10.

K03

11.

K04

FUSE BRACKET

12.

DC-DC CONNECTOR

RELAY (K06)

13.

MAIN WIRE HARNESS

RELAY (K14)

If DTC 9 still triggers, contact Nuvera for assistance.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 11-High coolant inlet temperature Tripping conditions Coolant inlet temperature TT304 ˃ 80°C for more than 3 seconds Action Shutdown System fault indicator on HMI is red and blinking Activation states Always

Diagnose and troubleshoot DTC 11 NOTE: Wait 15 minutes for fuel cell system to cool down before trying to restart. 1.

Has DTC 100 triggered also? YES - 5 VDC supply voltage to TT304 from VSM has failed causing a misreading. See DTC 100-5VDC supply of VSM Faulted or restart fuel cell. Contact Nuvera if DTC 100 occurs frequently. NO - Proceed to Step 2.

Is control valve TCV352 functioning properly? YES - Proceed to Step 3. NO - Check the following and replace if needed: • Connector V2 and V3 on VSM are plugged and properly wired. See Figure 8. • Pololu motor drive is plugged and properly wired.

Figure 8. VSM Connectors

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 11-High coolant inlet temperature (continued) Diagnose and troubleshoot DTC 11 (continued) 1.

V1 CONNECTOR

V4 CONNECTOR

V2 CONNECTOR

V5 CONNECTOR

V3 CONNECTOR

Are any of DTC's 25, 26, 27, or 35 triggering after restarting fuel cell? YES - Fuel cell system may need to be replaced. Contact Nuvera for assistance. NO - Proceed to Step 4.

Are any of DTC's 11, 12, 14, or 15 triggering after restarting fuel cell?

NOTE: Keep note if alarms due to high temperature start triggering at a higher rate. An occasional triggering of the alarm may be due to high ambient temperature. However, if occurrance rate increases, check the functionality of all coolant loop components. YES - Proceed to Step 5. NO - Check the functionality of all coolant loop components: • • • • 5.

Radiator (HX353) Fan (FAN365) Three-way valve Coolant pump (PMP351)

Is NTC expected resistance measurement consistent with room temperature?

NOTE: Check NTC expected resistance measurement. See Table 1. YES - If NTC expected resistance measurement is found to be consistent with room temperature, and DTC 11 still triggers, proceed to Step 6. NO - Replace TT304. See Replacing thermocouples (TT304 and TT351) in the Nuvera® Fuel Cell System Service Manual. NOTE: TT304 and TT351 are included in a set. If one is in need of being replaced, both must be replaced at that time. 6.

Is there enough coolant in fuel cell system?

NOTE: Warning DTC 53 (not shown on HMI but logged into CAN datalogger) may indicate a lack of coolant. YES - Proceed to Step 7. NO - Refill with Glysantin 50/50 if needed. See Draining and refilling coolant in the Nuvera® Fuel Cell System Service Manual. 7.

Is the radiator HX353 dirty? 22

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 11-High coolant inlet temperature (continued) Diagnose and troubleshoot DTC 11 (continued) YES - Clean the radiator by removing any dirt from its surface. NO - Proceed to Step 8. 8.

Is coolant loop leaking? YES - Check for leakage in coolant circuit and replace damaged component if needed. See Leak check coolant loop in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 9.

Is fan FAN365 functioning properly? Check if: • Fan is still spinning. • Fan is still spinning at desired speed. YES - Proceed to Step 11. NO - Check the following and replace if needed: • Connector V2 on VSM is plugged and properly wired. See Figure 8. • Fuse F08 and fan wiring. See Figure 9 or Figure 10. • DPS356 setting and wiring. See Figure 9 or Figure 10.

10. Is three-way valve functioning properly? YES - Proceed to Step 11. NO - See Replacing the three-way valve in the Nuvera® Fuel Cell System Service Manual. 11. Is coolant pump PMP351 functioning properly? NOTE: Warning DTC 53 (not shown on HMI but logged into CAN datalogger) may indicate a lack of coolant. Check if: • Pump is still spinning. • Pump is still spinning at desired speed. YES - Proceed to Step 12. NO - See Figure 9 or Figure 10 below. Check the following and replace if needed: • • • •

Connector V2 on VSM is plugged and properly wired Fuse F06 and contactors K06 and K03 Wiring between pump and DC/DC converter Wiring between batteries and DC/DC converter

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Diagnostic troubleshooting codes

DTC 11-High coolant inlet temperature (continued) Diagnose and troubleshoot DTC 11 (continued)

Figure 9. Electrical connectors (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) 1.

DC/DC CONNECTOR

BATTERY WIRING

FUSES

DPS WIRING

RELAY (K14)

RELAY (K06)

FAN CONNECTOR

PUMP CONNECTOR

K01

10.

K03

11.

K04

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Diagnostic troubleshooting codes

DTC 11-High coolant inlet temperature (continued) Diagnose and troubleshoot DTC 11 (continued)

Figure 10. Electrical connectors (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) 1.

BATTERY SYSTEM

BATTERY WIRING

FAN CONNECTOR

FUSES

K01

HIGH PRESSURE WIRE HARNESS

10.

K03

11.

K04

FUSE BRACKET

12.

DC-DC CONNECTOR

RELAY (K06)

13.

MAIN WIRE HARNESS

RELAY (K14)

12. If DTC 11 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 12-High coolant inlet temperature Tripping conditions Coolant inlet temperature TT304 ˃ 75°C for more than 15 seconds Action None System fault indicator on HMI is yellow Activation states Always

Diagnose and troubleshoot DTC 12 NOTE: Wait 15 minutes for fuel cell system to cool down before trying to restart. 1.

Has DTC 100 triggered also? YES - 5 VDC supply voltage to TT304 from VSM has failed causing a misreading. See DTC 100-5VDC supply of VSM Faulted or restart fuel cell system. Contact Nuvera if DTC 100 occurs frequently. NO - Proceed to Step 2.

Are any of DTC's 11, 12, 14, or 15 triggering after restarting fuel cell?

NOTE: Keep note if alarms due to high temperature start triggering at a higher rate. An occasional triggering of the alarm may be due to high ambient temperature. However, if occurrance rate increases, check the functionality of all coolant loop components. YES - Proceed to Step 3. NO - Check the functionality of all coolant loop components: • • • • 3.

Radiator (HX353) Fan (FAN365) Three-way valve Coolant pump (PMP351)

Is NTC expected resistance measurement consistent with room temperature?

NOTE: Check NTC expected resistance measurement. See Table 1. YES - If NTC expected resistance measurement is found to be consistent with room temperature, and DTC 12 still triggers, proceed to Step 4. NO - Replace TT304. See Replacing thermocouples (TT304 and TT351) in the Nuvera® Fuel Cell System Service Manual. NOTE: TT304 and TT351 are included in a set. If one is in need of being replaced, both must be replaced at that time. 4.

Is there enough coolant in fuel cell system? 26

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Diagnostic troubleshooting codes

DTC 12-High coolant inlet temperature (continued) Diagnose and troubleshoot DTC 12 (continued) NOTE: Warning DTC 53 (not shown on HMI but logged into CAN datalogger) may indicate a lack of coolant. YES - Proceed to Step 5. NO - Refill with Glysantin 50/50 if needed. See Draining and refilling coolant in the Nuvera® Fuel Cell System Service Manual. 5.

Is the radiator HX353 dirty? YES - Clean the radiator by removing any dirt from its surface. NO - Proceed to Step 6.

Is fan FAN365 functioning properly? Check if: • Fan is still spinning. • Fan is still spinning at desired speed. YES - Proceed to Step 9. NO - Check the following and replace if needed: • Connector V2 on VSM is plugged and properly wired. • Fuse F08 and fan wiring. See Figure 11 or Figure 12. • DPS356 setting and wiring. See Figure 11 or Figure 12.

Is three-way valve functioning properly? YES - Proceed to Step 9. NO - See Replacing the three-way valve in the Nuvera® Fuel Cell System Service Manual.

Is coolant pump PMP351 functioning properly?

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Diagnostic troubleshooting codes

DTC 12-High coolant inlet temperature (continued) Diagnose and troubleshoot DTC 12 (continued) • • • •

Connector V2 on VSM is plugged and properly wired Fuse F06 and contactors K06 and K03 Wiring between pump and DC/DC converter Wiring between batteries and DC/DC converter

Figure 11. Electrical connectors (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) 1.

DC/DC CONNECTOR

BATTERY WIRING

FUSES

DPS WIRING

RELAY (K14)

RELAY (K06)

FAN CONNECTOR

PUMP CONNECTOR

K01

10.

K03

11.

K04

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Diagnostic troubleshooting codes

DTC 12-High coolant inlet temperature (continued) Diagnose and troubleshoot DTC 12 (continued)

Figure 12. Electrical connectors (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) 1.

BATTERY SYSTEM

BATTERY WIRING

FAN CONNECTOR

FUSES

K01

HIGH PRESSURE WIRE HARNESS

10.

K03

11.

K04

FUSE BRACKET

12.

DC-DC CONNECTOR

RELAY (K06)

13.

MAIN WIRE HARNESS

RELAY (K14)

10. If DTC 12 still triggers, contact Nuvera for assistance.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 14-High coolant outlet temperature Tripping conditions Coolant outlet temperature TT351 ˃ 86°C for more than 3 seconds Action Shutdown System fault indicator on HMI is red and blinking Activation states Always

Diagnose and troubleshoot DTC 14 NOTE: Wait 15 minutes for fuel cell system to cool down before trying to restart. 1.

Is control valve TCV352 functioning properly? YES - Proceed to Step 3. NO - Check the following and replace if needed: • Connector V2 and V3 on VSM are plugged and properly wired. See Figure 13. • Pololu motor drive is plugged and properly wired.

Figure 13. VSM Connectors

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Diagnostic troubleshooting codes

DTC 14-High coolant outlet temperature (continued) Diagnose and troubleshoot DTC 14 (continued) 1.

V1 CONNECTOR

V4 CONNECTOR

V2 CONNECTOR

V5 CONNECTOR

V3 CONNECTOR

Are any of DTC's 25, 26, 27, or 35 triggering after restarting fuel cell? YES - Fuel cell system may need to be replaced. Contact Nuvera for assistance. NO - Proceed to Step 4.

Are any of DTC's 11, 12, 14, or 15 triggering after restarting fuel cell?

Radiator (HX353) Fan (FAN365) Three-way valve Coolant pump (PMP351)

Is NTC expected resistance measurement consistent with room temperature?

NOTE: Check NTC expected resistance measurement. See Table 1. YES - If NTC expected resistance measurement is found to be consistent with room temperature, and DTC 14 still triggers, proceed to Step 6. NO - Replace TT304. See Replacing thermocouples (TT304 and TT351) in the Nuvera® Fuel Cell System Service Manual. NOTE: TT304 and TT351 are included in a set. If one is in need of being replaced, both must be replaced at that time. 6.

Is there enough coolant in fuel cell system?

Is the radiator HX353 dirty? 31

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Diagnostic troubleshooting codes

DTC 14-High coolant outlet temperature (continued) Diagnose and troubleshoot DTC 14 (continued) YES - Clean the radiator by removing any dirt from its surface. NO - Proceed to Step 8. 8.

Is fan FAN365 functioning properly? Check if: • Fan is still spinning. • Fan is still spinning at desired speed. YES - Proceed to Step 11. NO - Check the following and replace if needed: • Connector V2 on VSM is plugged and properly wired. See Figure 13. • Fuse F08 and fan wiring. See Figure 14 or Figure 15. • DPS356 setting and wiring. See Figure 14 or Figure 15.

10. Is three-way valve functioning properly? YES - Proceed to Step 11. NO - See Replacing the three-way valve in Nuvera® Fuel Cell System Service Manual. 11. Is coolant pump PMP351 functioning properly? NOTE: Warning DTC 53 (not shown on HMI but logged into CAN datalogger) may indicate a lack of coolant. Check if: • Pump is still spinning. • Pump is still spinning at desired speed. YES - Proceed to Step 12. NO - See Figure 14 or Figure 15 below. Check the following and replace if needed: • • • •

Connector V2 on VSM is plugged and properly wired Fuse F06 and contactors K06 and K03 Wiring between pump and DC/DC converter Wiring between batteries and DC/DC converter

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Diagnostic troubleshooting codes

DTC 14-High coolant outlet temperature (continued) Diagnose and troubleshoot DTC 14 (continued)

Figure 14. Electrical connectors (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) 1.

DC/DC CONNECTOR

BATTERY WIRING

FUSES

DPS WIRING

RELAY (K14)

RELAY (K06)

FAN CONNECTOR

PUMP CONNECTOR

K01

10.

K03

11.

K04

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Diagnostic troubleshooting codes

DTC 14-High coolant outlet temperature (continued) Diagnose and troubleshoot DTC 14 (continued)

Figure 15. Electrical connectors (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) 1.

BATTERY SYSTEM

BATTERY WIRING

FAN CONNECTOR

FUSES

K01

HIGH PRESSURE WIRE HARNESS

10.

K03

11.

K04

FUSE BRACKET

12.

DC-DC CONNECTOR

RELAY (K06)

13.

MAIN WIRE HARNESS

RELAY (K14)

12. If DTC 14 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 15-High coolant outlet temperature Tripping conditions Coolant outlet temperature TT351 ˃ 81°C for more than 15 seconds Action None Coolant temperature indicator on HMI is red and blinking Activation states Always

Diagnose and troubleshoot DTC 15 NOTE: Wait 15 minutes for fuel cell system to cool down before trying to restart. 1.

Has DTC 100 triggered also? YES - 5 VDC supply voltage to TT351 from VSM has failed causing a misreading. See DTC 100-5VDC supply of VSM Faulted or restart fuel cell system. Contact Nuvera if DTC 100 occurs frequently. NO - Proceed to Step 2.

Are any of DTC's 11, 12, 14, or 15 triggering after restarting fuel cell?

NOTE: Keep note if alarms due to high temperature start triggering at a higher rate. An occasional triggering of the alarm may be due to high ambient temperature. However, if occurrance rate increases, check the functionality of all coolant loop components. YES - Proceed to Step 3. NO - Check the functionality of all coolant loop components: • • • • 3.

Radiator (HX353) Fan (FAN365) Three-way valve Coolant pump (PMP351)

Is NTC expected resistance measurement consistent with room temperature?

NOTE: Check NTC expected resistance measurement. See Table 1. YES - If NTC expected resistance measurement is found to be consistent with room temperature, and DTC 15 still triggers, proceed to Step 4. NO - Replace TT351. See Replacing thermocouples (TT304 and TT351) in the Nuvera® Fuel Cell System Service Manual. NOTE: TT304 and TT351 are included in a set. If one is in need of being replaced, both must be replaced at that time. 4.

Is there enough coolant in fuel cell system? 35

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Diagnostic troubleshooting codes

DTC 15-High coolant outlet temperature (continued) Diagnose and troubleshoot DTC 15 (continued) NOTE: Warning DTC 53 (not shown on HMI but logged into CAN datalogger) may indicate a lack of coolant. YES - Proceed to Step 5. NO - Refill with Glysantin 50/50 if needed. See Draining and refilling coolant in the Nuvera® Fuel Cell System Service Manual. 5.

Is the radiator HX353 dirty? YES - Clean the radiator by removing any dirt from its surface. NO - Proceed to Step 6.

Is fan FAN365 functioning properly? Check if: • Fan is still spinning. • Fan is still spinning at desired speed. YES - Proceed to Step 9. NO - Check the following and replace if needed: • Connector V2 on VSM is plugged and properly wired. • Fuse F08 and fan wiring. See Figure 16 or Figure 17. • DPS356 setting and wiring. See Figure 16 or Figure 17.

Is three-way valve functioning properly? YES - Proceed to Step 9. NO - See Replacing the three-way valve in the Nuvera® Fuel Cell System Service Manual.

Is coolant pump PMP351 functioning properly?

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Diagnostic troubleshooting codes

DTC 15-High coolant outlet temperature (continued) Diagnose and troubleshoot DTC 15 (continued) • • • •

Connector V2 on VSM is plugged and properly wired Fuse F06 and contactors K06 and K03 Wiring between pump and DC/DC converter Wiring between batteries and DC/DC converter

Figure 16. Electrical connectors (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) 1.

DC/DC CONNECTOR

BATTERY WIRING

FUSES

DPS WIRING

RELAY (K14)

RELAY (K06)

FAN CONNECTOR

PUMP CONNECTOR

K01

10.

K03

11.

K04

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Diagnostic troubleshooting codes

DTC 15-High coolant outlet temperature (continued) Diagnose and troubleshoot DTC 15 (continued)

Figure 17. Electrical connectors (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) 1.

BATTERY SYSTEM

BATTERY WIRING

FAN CONNECTOR

FUSES

K01

HIGH PRESSURE WIRE HARNESS

10.

K03

11.

K04

FUSE BRACKET

12.

DC-DC CONNECTOR

RELAY (K06)

13.

MAIN WIRE HARNESS

RELAY (K14)

10. If DTC 15 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 16-High coolant outlet temperature Tripping conditions Coolant outlet temperature TT351 ˃ 81°C for more than 1 second Action None Coolant temperature indicator on HMI is yellow Activation states Always

Diagnose and troubleshoot DTC 16 NOTE: Wait 15 minutes for fuel cell system to cool down before trying to restart. 1.

Are any of DTC's 11, 12, 14, or 15 triggering after restarting fuel cell?

NOTE: Keep note if alarms due to high temperature start triggering at a higher rate. An occasional triggering of the alarm may be due to high ambient temperature. However, if occurrance rate increases, check the functionality of all coolant loop components. YES - Proceed to Step 3. NO - Check the functionality of all coolant loop components: • • • • 3.

Radiator (HX353) Fan (FAN365) Three-way valve Coolant pump (PMP351)

Is NTC expected resistance measurement consistent with room temperature?

NOTE: Check NTC expected resistance measurement. See Table 1. YES - If NTC expected resistance measurement is found to be consistent with room temperature, and DTC 16 still triggers, proceed to Step 4. NO - Replace TT351. See Replacing thermocouples (TT304 and TT351) in the Nuvera® Fuel Cell System Service Manual. NOTE: TT304 and TT351 are included in a set. If one is in need of being replaced, both must be replaced at that time. 4.

Is there enough coolant in fuel cell system? 39

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Diagnostic troubleshooting codes

DTC 16-High coolant outlet temperature (continued) Diagnose and troubleshoot DTC 16 (continued) NOTE: Warning DTC 53 (not shown on HMI but logged into CAN datalogger) may indicate a lack of coolant. YES - Proceed to Step 5. NO - Refill with Glysantin 50/50 if needed. See Draining and refilling coolant in the Nuvera® Fuel Cell System Service Manual. 5.

Is the radiator HX353 dirty? YES - Clean the radiator by removing any dirt from its surface. NO - Proceed to Step 6.

Is fan FAN365 functioning properly? Check if: • Fan is still spinning. • Fan is still spinning at desired speed. YES - Proceed to Step 9. NO - Check the following and replace if needed: • Connector V2 on VSM is plugged and properly wired. • Fuse F08 and fan wiring. See Figure 18 or Figure 19. • DPS356 setting and wiring. See Figure 18 or Figure 19.

Is three-way valve functioning properly? YES - Proceed to Step 9. NO - See Replacing the three-way valve in the Nuvera® Fuel Cell System Service Manual.

Is coolant pump PMP351 functioning properly?

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Diagnostic troubleshooting codes

DTC 16-High coolant outlet temperature (continued) Diagnose and troubleshoot DTC 16 (continued) NO - See Figure 18 or Figure 19 below. Check the following and replace if needed: • • • •

Connector V2 on VSM is plugged and properly wired Fuse F06 and contactors K06 and K03 Wiring between pump and DC/DC converter Wiring between batteries and DC/DC converter

Figure 18. Electrical connectors (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) 1.

DC/DC CONNECTOR

BATTERY WIRING

FUSES

DPS WIRING

RELAY (K14)

RELAY (K06)

FAN CONNECTOR

PUMP CONNECTOR

K01

10.

K03

11.

K04

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Diagnostic troubleshooting codes

DTC 16-High coolant outlet temperature (continued) Diagnose and troubleshoot DTC 16 (continued)

Figure 19. Electrical connectors (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) 1.

BATTERY SYSTEM

BATTERY WIRING

FAN CONNECTOR

FUSES

K01

HIGH PRESSURE WIRE HARNESS

10.

K03

11.

K04

FUSE BRACKET

12.

DC-DC CONNECTOR

RELAY (K06)

13.

MAIN WIRE HARNESS

RELAY (K14)

10. If DTC 16 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 17-High cathode inlet temperature Tripping conditions Cathode inlet temperature TT208 ˃ 80°C for more than 30 seconds Action None System fault indicator on HMI is yellow Activation states Always

Diagnose and troubleshoot DTC 17 1. Is DTC 17 occurring more than once in a 24 hour period? YES - Proceed to Step 2. NO - Return to service. 2.

Is the air cooler HX202 dirty? YES - Clean the radiator by removing any dirt from its surface NO - Proceed to Step 3.

Is air cooler HX202 leaking? YES - Check radiator for any leakage. Replace radiator if necessary. See Removing and installing the radiator in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 4.

Are fans FAN354 functioning properly? YES - Proceed to Step 5. NO - Check connector V2 on VSM is plugged and properly wired. See Figure 20. Check fuse F07 and fan wiring. Replace if needed.

Is DTC 22 triggering also? YES - Dewater condensate tank. If DTC 17 and 22 are still triggering, proceed to Step 7. NO - Proceed to Step 6.

Is DTC 17 still triggering more than once in a 24 hour period? YES - Proceed to Step 7. NO - Return to service.

Check that there is no obstruction in the humidifier and/or exhaust line. If DTC 17 and 22 are still triggering, proceed to Step 8.

Check that CV251 is correctly installed and is functioning properly. If DTC 17 is still triggering, proceed to Step 9. 43

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Diagnostic troubleshooting codes

DTC 17-High cathode inlet temperature (continued) Diagnose and troubleshoot DTC 17 (continued) 9.

Check that air compressor and its motor drive are functioning properly. If air compressor and motor drive are functioning properly and DTC 17 is still triggering, proceed to Step 10.

Figure 20. VSM Connectors 1.

V1 CONNECTOR

V2 CONNECTOR

V3 CONNECTOR

V4 CONNECTOR

V5 CONNECTOR

10. If DTC 17 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 18-High anode outlet pressure Tripping conditions PT157 ˃ 3 bara for more than 500 ms Action Warning Red fault notification (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) Logged warning (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) Activation states Always

Diagnose and troubleshoot DTC 18 1. Has the power from the fuel cell immediately cut out (with no truck connection to ultracaps soon after shutdown)? YES - Proceed to Step 2. NO - Check if PS104 is properly working and is properly wired. Replace if needed. 2.

Has DTC 95 triggered also? YES - Follow procedure for troubleshooting DTC 95-Anode over-pressure. NO - Proceed to Step 3.

If DTC 18 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 19-High anode outlet pressure Tripping conditions PT157 ˃ 2.5 bara for more than 3 seconds Action None System fault indicator on HMI is yellow Activation states Always

Diagnose and troubleshoot DTC 19 1. Is DTC 19 occurring more than once in a 24 hour period? YES - Proceed to Step 2. NO - Return to service. 2.

Is DTC 63 triggering also? YES - Proceed to Step 3. NO - Proceed to Step 5.

Is PCV193 properly set and properly functioning? YES - Proceed to Step 4. NO - Have PCV193 set and confirm it is functioning properly. Replace if needed. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual.

Is PCV192 properly set and properly functioning? YES - Proceed to Step 5. NO - Have PCV192 set and confirm it is functioning properly. Replace if needed. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual.

Is FV194 functioning properly? YES - Proceed to Step 7. NO - Replace FV194. See Replacing FV194 and OR198 in the Nuvera® Fuel Cell System Service Manual.

Is the ejector PCE103 functioning properly? YES - Proceed to Step 7. NO - Replace PCE103. See Replacing the ejector (PCE103) in the Nuvera® Fuel Cell System Service Manual.

Is DTC 22 triggering also? YES - Make sure no occlusion on cathode side is in place and perform the following checks: 46

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Diagnostic troubleshooting codes

DTC 19-High anode outlet pressure (continued) Diagnose and troubleshoot DTC 19 (continued) • Check exhaust hose is not clogged and/or pinched • Check condensate tank exit is not clogged • Check CV251 is correctly mounted and is functioning properly • Check humidifier (wet and dry sides) is not clogged and gaskets are properly in place • Check fuel-cell is not clogged and gaskets are properly in place • Check cathode cooler HX202 is not clogged NO - Proceed to Step 8. 8.

If DTC 19 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 20-Low anode outlet pressure Tripping conditions 50 mbara ˂ PT157 ˂ 1300 mbara for more than 500 ms Action Immediate shutdown of fuel cell System fault indicator on HMI is red and blinking Activation states From start-up to shutdown

Diagnose and troubleshoot DTC 20 1. Is fuel tank on HMI red and blinking? (DTC 80) YES - Refuel tank. NO - Proceed to Step 2. 2.

Has DTC 100 triggered also? YES - 5 VDC supply voltage to PT157 from VSM has failed causing a misreading of PT157. See DTC 100-5VDC supply of VSM Faulted or restart fuel cell system and contact Nuvera if DTC 100 occurs frequently. NO - Proceed to Step 3.

Is HV183 closed? YES - Open HV183. See Figure 21. NO - Proceed to Step 4.

Is XV101 plugged and properly functioning (Item 7, Figure 21)? YES - Proceed to Step 5. NO - Fix any electrical and mechanical issue necessary to make XV101 function properly. Replace if needed. See Replacing solenoid valve (XV101) in the Nuvera® Fuel Cell System Service Manual.

Is XV191 plugged and properly functioning (Item 1, Figure 21)? YES - Proceed to Step 6. NO - Fix any electrical and mechanical issue necessary to make XV191 function properly. A replacement may be necessary, however XV191 may not be replaced individually. The entire fuel storage tank must be replaced. Contact Nuvera for assistance.

Is PCV193 set and properly functioning (Item 4, Figure 21)? YES - Proceed to Step 7. NO - Have PCV193 set and confirm it is functioning properly. Replace if needed. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual.

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Diagnostic troubleshooting codes

DTC 20-Low anode outlet pressure (continued) Diagnose and troubleshoot DTC 20 (continued)

Figure 21. Fuel system 1.

XV191

HV195

HV183

FV194

PT102

XV101

PCV192 AND PCV193

PT189

Is PCV192 set and properly functioning (Item 4, Figure 21)? YES - Proceed to Step 8. NO - Have PCV192 set and confirm it is functioning properly. Replace if needed. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual.

Is FV194 stuck closed (Item 6, Figure 21)? YES - Replace FV194. See Replacing FV194 and OR198 in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 9.

Is FL190 clogged? YES - Replace FL190. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 10.

10. Is OR198 clogged? 49

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Diagnostic troubleshooting codes

DTC 20-Low anode outlet pressure (continued) Diagnose and troubleshoot DTC 20 (continued) YES - Replace OR198. See Replacing FV194 and OR198 in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 12. 11. Is the ejector PCE103 functioning properly? YES - Proceed to Step 12. NO - Replace PCE103. See Replacing the ejector (PCE103) in the Nuvera® Fuel Cell System Service Manual. 12. Have DTC's 95, 18, 19, or 63 recently triggered? YES - Look for possible hydrogen leakage. NO - Proceed to Step 13. 13. If DTC 20 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 21-Low anode outlet pressure Tripping conditions 50 mbara ˂ PT157 ˂ 1350 mbara for more than 1 s Action Shutdown System fault indicator on HMI is red and blinking Activation states From start-up to shutdown

Diagnose and troubleshoot DTC 21 1. Is fuel tank on HMI blinking red? (DTC 80) YES - Refuel tank. NO - Proceed to Step 2. 2.

Is HV183 closed? YES - Open HV183. See Figure 22. NO - Proceed to Step 4.

Is XV101 plugged and properly functioning (Item 7, Figure 22)? YES - Proceed to Step 5. NO - Fix any electrical and mechanical issue necessary to make XV101 function properly. Replace if needed. See Replacing solenoid valve (XV101) in the Nuvera® Fuel Cell System Service Manual.

Is XV191 plugged and properly functioning (Item 1, Figure 22)? YES - Proceed to Step 6. NO - Fix any electrical and mechanical issue necessary to make XV191 function properly. A replacement may be necessary, however XV191 may not be replaced individually. The entire fuel storage tank must be replaced. Contact Nuvera for assistance.

Is PCV193 set and properly functioning (Item 4, Figure 22)? YES - Proceed to Step 7. NO - Have PCV193 set and confirm it is functioning properly. Replace if needed. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

DTC 21-Low anode outlet pressure (continued) Diagnose and troubleshoot DTC 21 (continued)

Figure 22. Fuel system 1.

XV191

HV195

HV183

FV194

PT102

XV101

PCV192 AND PCV193

PT189

Is PCV192 set and properly functioning (Item 4, Figure 22)? YES - Proceed to Step 8. NO - Have PCV192 set and confirm it is functioning properly. Replace if needed. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual.

Is FV194 stuck closed (Item 6, Figure 22)? YES - Replace FV194. See Replacing FV194 and OR198 in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 9.

Is FL190 clogged? YES - Replace FL190. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 10.

10. Is OR198 clogged? 52

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Diagnostic troubleshooting codes

DTC 21-Low anode outlet pressure (continued) Diagnose and troubleshoot DTC 21 (continued) YES - Replace OR198. See Replacing FV194 and OR198 in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 12. 11. Is the ejector PCE103 functioning properly? YES - Proceed to Step 12. NO - Replace PCE103. See Replacing the ejector (PCE103) in the Nuvera® Fuel Cell System Service Manual. 12. Have DTC's 95, 18, 19, or 63 recently triggered? YES - Look for possible hydrogen leakage. NO - Proceed to Step 13. 13. If DTC 21 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 22-High cathode inlet pressure Tripping conditions Cathode inlet pressure ˃ 1.8 bara for more than 3 seconds Action None System fault indicator on HMI is yellow Activation states From RUN state through shutdown

Diagnose and troubleshoot DTC 22 1. Dewater condensate tank. If DTC 22 is still triggering more than once in a 24 hour period, proceed to Step 2. 2.

Are DTC 17 or 54 triggering also? YES - Trican sensor may need to be replaced. Contact Nuvera for assistance. NO - Proceed to Step 3.

Check if CV251 is installed and functioning properly. YES - Proceed to Step 4. NO - Remove CV251 and re-install correctly.

Have DTC 88 or DTC 89 triggered also? YES - See motor controller troubleshooting procedures DTC 88-Motor controller error status and DTC 89-Motor controller warning status. NO - Proceed to Step 5.

If DTC 22 is still triggering frequently, confirm proper firmware is loaded on motor controller. YES - Proceed to Step 6. NO - Update firmware.

If DTC 22 still triggers frequently, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 25-Minimum cell voltage Tripping conditions Minimum cell voltage ˂ 0 mV for more than 250 ms Action Immediate shutdown System fault indicator on HMI is red and blinking Activation states From RUN state through shutdown

Diagnose and troubleshoot DTC 25 1. Check all electrical connections from stack (BoB) to CVM.

Figure 23. CVM connectors 1.

CONN 1

CONN 7

CONN 2

CONN 8

CONN 3

CONN 9

CONN 4

10.

CONN 10

CONN 5

11.

CONN 11

CONN 6

12.

CONN 12

NOTE: DTC 32 applies only to fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R. 2.

Is more than one cell dropping down?

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Diagnostic troubleshooting codes

DTC 25-Minimum cell voltage (continued) Diagnose and troubleshoot DTC 25 (continued) YES - Check that the air compressor and motor drive are functioning properly. DTC's 32, 36, 86, 88, and 89 may indicate an issue with the air compressor. NO - Proceed to Step 3. 3.

Has DTC 22 recently triggered also? YES - Perform the following steps: • Dewater condensate tank • Check for obstruction in humidifier and/or exhaust line • Check that CV251 is properly installed and is properly working NO - Proceed to Step 4.

Have one or more of DTC's 20, 21, 33, 34, and 80 triggered recently?

NOTE: Low cell voltage may be due to anode starvation. Confirm fuel cell is properly fed by hydrogen. YES - Refer to the troubleshooting procedure for the triggered DTC. NO - Proceed to Step 5. 5.

Check F02, K02 functionality and HTR303 resistance. Expected resistance of HTR303 is 9.6Ω. If the value is lower, replace HTR303. If HTR303 is functioning properly, proceed to Step 6.

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Diagnostic troubleshooting codes

DTC 25-Minimum cell voltage (continued) Diagnose and troubleshoot DTC 25 (continued)

Figure 24. Heater (HTR303) 1.

CONDENSATE TANK

HEATER

Is purge valve (XV155) functioning properly? YES - Proceed to Step 7. NO - Fix any electrical and mechanical issue needed to make XV155 function properly. Replace if needed. See Replacing drain valve (XV154) and purge valve (XV155) in the Nuvera® Fuel Cell System Service Manual.

Is drain valve (XV154) functioning properly? YES - Proceed to Step 8. NO - Fix any electrical and mechanical issue needed to make XV154 function properly. Replace if needed. See Replacing drain valve (XV154) and purge valve (XV155) in the Nuvera® Fuel Cell System Service Manual.

Is fuel cell system being fed with proper quality grade hydrogen? YES - Proceed to Step 9. NO - Properly vent the hydrogen tank and refill with proper quality grade hydrogen.

If DTC 25 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 26-Minimum cell voltage Tripping conditions Minimum cell voltage ˂ 300 mV for more than 3 seconds Action Shutdown System fault indicator on HMI is red and blinking Activation states From RUN state through shutdown

Diagnose and troubleshoot DTC 26 1. Check all electrical connections from stack (BoB) to CVM.

Figure 25. CVM connectors 1.

CONN 1

CONN 7

CONN 2

CONN 8

CONN 3

CONN 9

CONN 4

10.

CONN 10

CONN 5

11.

CONN 11

CONN 6

12.

CONN 12

NOTE: DTC 32 applies only to fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R. 2.

Is more than one cell dropping down?

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Diagnostic troubleshooting codes

DTC 26-Minimum cell voltage (continued) Diagnose and troubleshoot DTC 26 (continued) YES - Check that the air compressor and motor drive are functioning properly. DTC's 32, 36, 86, 88, and 89 may indicate an issue with the air compressor. NO - Proceed to Step 3. 3.

Have one or more of DTC's 20, 21, 33, 34, and 80 triggered recently?

NOTE: Low cell voltage may be due to anode starvation. Confirm fuel cell is properly fed by hydrogen. YES - Refer to the troubleshooting procedure for the triggered DTC. NO - Proceed to Step 5. 5.

Check F02, K02 functionality and HTR303 resistance. Expected resistance of HTR303 is 9.6Ω. If the value is lower, replace HTR303 (See Figure 26). If HTR303 is functioning properly, proceed to Step 6.

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Diagnostic troubleshooting codes

DTC 26-Minimum cell voltage (continued) Diagnose and troubleshoot DTC 26 (continued)

Figure 26. Heater (HTR303) 1.

CONDENSATE TANK

HEATER

Is fuel cell system being fed with proper quality grade hydrogen? YES - Proceed to Step 9. NO - Properly vent the hydrogen tank and refill with proper quality grade hydrogen. See Vent hydrogen from engine plumbing lines in the Nuvera® Fuel Cell System Service Manual.

If DTC 26 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 27-Minimum cell voltage Tripping conditions Minimum cell voltage ˂ 400 mV for more than 3 seconds Action None System fault indicator on HMI is yellow Activation states From RUN state through shutdown

Diagnose and troubleshoot DTC 27 1. Is DTC 27 occurring more than once in a 24 hour period? YES - Check all electrical connections from stack (BoB) to CVM. NO - Proceed to Step 2. 2.

Is DTC 27 triggering frequently together with DTC 22 ? YES - Perform the following steps: • Dewater condensate tank • Check for obstruction in humidifier and/or exhaust line • Check that CV251 is properly installed and is properly working NO - Proceed to Step 3.

Is DTC 27 still triggering frequently? YES - Proceed to Step 4.

Is purge valve (XV155) functioning properly? YES - Proceed to Step 5. NO - Fix any electrical and mechanical issue needed to make XV155 function properly. Replace if needed. See Replacing drain valve (XV154) and purge valve (XV155) in the Nuvera® Fuel Cell System Service Manual.

Is drain valve (XV154) functioning properly? YES - Proceed to Step 6. NO - Fix any electrical and mechanical issue needed to make XV154 function properly. Replace if needed. See Replacing drain valve (XV154) and purge valve (XV155) in the Nuvera® Fuel Cell System Service Manual.

Is fuel cell system being fed with proper quality grade hydrogen? YES - Proceed to Step 7. NO - Properly vent the hydrogen tank and refill with proper quality grade hydrogen. See Vent hydrogen from engine plumbing lines in the Nuvera® Fuel Cell System Service Manual. 61

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Diagnostic troubleshooting codes

DTC 27-Minimum cell voltage (continued) Diagnose and troubleshoot DTC 27 (continued) 7.

If DTC 27 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 28-Low anode purge (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) Tripping conditions PT157 decrease ˂ 50 mbara, when stack current ≤ 25 A, for 3 times in a row Action None Software version 2.0.0: Yellow fault notification Software version 2.0.4: Logged warning Activation states None NOTE: In general, a proficient purge when fuel cell system is running determines a 100 ÷ 150 mbar anode pressure decrease during purge event in respect to normal anode pressure (i.e when anode is not purged). Since anode pressure also changes depending on fuel cell current, the verification is made at low current while fuel cell system is going to enter stand-by mode. In this condition anode pressure is only slightly affected by fuel cell current and a better evaluation can be made. In running mode at higher current, a better evaluation would be possible only if fuel cell current is kept constant between two consecutive purge events (and the purge event itself).

Diagnose and troubleshoot DTC 28 1. Is purge port in the stack manifold assembly blocked? YES - Check that gasket is is not partiall or totally blocking purge port. Fix position. Replace if needed. NO - Proceed to Step 2. 2.

Is anode purge valve (XV154) working properly?

NOTE: The sound of the solenoid when the valve is switched is generally a good indication of valves behavior. YES - Proceed to Step 3. NO - Fix any electrical and mechanical issue to get XV154 working properly. Replace if needed. 3.

If DTC 21 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 32-Low stack bypass airflow (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) Tripping conditions Stack bypass airflow ˂ 90% Cathode Stack bypass airflow set-point for more than 10 seconds Action Shutdown System fault indicator on HMI is red and blinking. Activation states Start-up (dilution start)

Diagnose and troubleshoot DTC 32 NOTE: Follow Step 1. through Step 10. if the compressor is NOT running. If the compressor IS running, skip to Step 11. 1.

Have DTC 88 and/or DTC 89 triggered? YES - Follow troubleshooting procedure in DTC 88-Motor controller error status and DTC 89-Motor controller warning status. NO - Proceed to Step 2.

Is motor controller communicating with the VSM? YES - Proceed to Step 6. NO - Check fuse F06 and contactor K06 (see Figure 27). Replace if necessary. See the Nuvera® Fuel Cell System Service Manual.

Is the 35-pin connector of the motor controller plugged properly? YES - Proceed to Step 4. NO - Check and fix any electrical issue to the 35-pin connector of the motor controller.

Is CAN bus resistance equal to 120 Ohms? YES - Proceed to Step 5. NO - Check and fix any electrical issue to the CAN bus channel 2.

Is the VSM sending messages on CAN bus channel 2? YES - Proceed to Step 10. NO - Check and fix any electrical issue to the CAN bus channel 2.

Is the voltage from the ultracaps too low? YES - Start fuel cell system and wait 15 minutes for ultracapacitors to be recharged. Proceed to Step 7. NO - Proceed to Step 8.

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Diagnostic troubleshooting codes

DTC 32-Low stack bypass airflow (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) (continued) Diagnose and troubleshoot DTC 32 (continued)

Figure 27. Electrical connectors 1.

DC/DC CONNECTOR

BATTERY WIRING

FUSES

DPS WIRING

RELAY (K14)

RELAY (K06)

FAN CONNECTOR

PUMP CONNECTOR

K01

10.

K03

11.

K04

Have ultracapacitors been charged? YES - Proceed to Step 8. NO - Perform the following: • Check battery voltage and recharge if necessary. • Check battery wiring and ultracapacitor wiring.

Has Fuse F05 blown or has relay K3 failed open? 65

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Diagnostic troubleshooting codes

DTC 32-Low stack bypass airflow (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) (continued) Diagnose and troubleshoot DTC 32 (continued) YES - Replace fuse F05 and/or relay K03. See the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 9. 9.

Is the 48VDC supply applied properly? YES - Proceed to Step 10. NO - Check wiring between ultracapacitors and motor controller.

10. If DTC 32 still triggers, contact Nuvera for assistance. NOTE: Follow steps below if the compressor IS running. 11. Is data from TRICAN sensor properly logged? YES - Proceed to Step 15. NO - Proceed to Step 12. 12. Is CAN bus of channel 1 either faulted or loaded with a large number of errors? YES - Proceed to Step 13. NO - Check if bus is properly terminated. 13. Is CAN bus of channel 1 properly loaded with messages from TRICAN sensor? YES - Proceed to Step 14. NO - Check and fix any electrical issue to the CAN bus channel 1. 14. Is the correct firmware loaded on the motor controller? YES - Proceed to Step 15. NO - Check firmware loaded on motor controller. Update if necessary. 15. If DTC 32 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 33-Low anode outlet pressure at start-up Tripping conditions 50 mbara ˂ PT157 ˂ 1500 mbara for more than 20 seconds Action Shutdown System fault indicator on HMI is red and blinking Activation states Anode pressurization at start-up

Diagnose and troubleshoot DTC 33 1. Is fuel pump on HMI red and blinking? (DTC 80) YES - Refuel tank. NO - Proceed to Step 2. 2.

Is manual lockdown (HV183) closed? YES - Open HV183. See Figure 28. NO - Proceed to Step 4.

Is solenoid valve (XV101) plugged and properly functioning (Item 7, Figure 28)? YES - Proceed to Step 5. NO - Fix any electrical and mechanical issue necessary to make XV101 function properly. Replace if needed. See Replacing solenoid valve (XV101) in the Nuvera® Fuel Cell System Service Manual.

Is shutoff valve (XV191) plugged and properly functioning (Item 1, Figure 28)? YES - Proceed to Step 6. NO - Fix any electrical and mechanical issue necessary to make XV191 function properly. A replacement may be necessary, however XV191 may not be replaced individually. The entire fuel storage tank must be replaced. Contact Nuvera for assistance.

Is PCV193 set and properly functioning (Item 4, Figure 28)? YES - Proceed to Step 7. NO - Have PCV193 set and confirm it is functioning properly. Replace if needed. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual. 67

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Diagnostic troubleshooting codes

DTC 33-Low anode outlet pressure at start-up (continued) Diagnose and troubleshoot DTC 33 (continued)

Figure 28. Fuel system 1.

XV191

HV195

HV183

FV194

PT102

XV101

PCV192 AND PCV193

PT189

NOTE: FL190, PCV192, and PCV193 are all components of the regulator. 7.

Is PCV192 set and properly functioning (Item 4, Figure 28)? YES - Proceed to Step 8. NO - Have PCV192 set and confirm it is functioning properly. Replace if needed. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual.

Is excess flow valve (FV194) stuck closed (Item 6, Figure 28)? YES - Replace FV194. See Replacing FV194 and OR198 in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 9.

Is FL190 clogged? YES - Replace FL190. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual. 68

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Diagnostic troubleshooting codes

DTC 33-Low anode outlet pressure at start-up (continued) Diagnose and troubleshoot DTC 33 (continued) NO - Proceed to Step 10. 10. Is adapter (OR198) clogged? YES - Replace OR198. See Replacing FV194 and OR198 in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 11. 11. Have DTC's 95, 18, 19, or 63 recently triggered? YES - Look for possible hydrogen leakage. NO - Proceed to Step 12. 12. If DTC 33 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 34-Low anode supply pressure Tripping conditions 50 mbara ˂ PT102 ˂ 7000 mbara for more than 20 seconds Action Shutdown System fault indicator on HMI is red and blinking Activation states Anode pressurization at start-up

Diagnose and troubleshoot DTC 34 1. Is fuel pump on HMI red and blinking? (DTC 80) YES - Refuel tank. NO - Proceed to Step 2. 2.

Has DTC 100 triggered also? YES - 5 VDC supply voltage to PT102 from VSM has failed causing a misreading of PT102. See DTC 100-5VDC supply of VSM Faulted or restart fuel cell system and contact Nuvera if DTC 100 occurs frequently. NO - Proceed to Step 3.

Is manual lockdown (HV183) closed? YES - Open HV183. See Figure 29. NO - Proceed to Step 4.

Is shutoff valve (XV191) plugged and properly functioning (Item 1, Figure 29)? YES - Proceed to Step 5. NO - Fix any electrical and mechanical issue necessary to make XV191 function properly. A replacement may be necessary, however XV191 may not be replaced individually. The entire fuel storage tank must be replaced. Contact Nuvera for assistance.

Is PCV193 set and properly functioning (Item 4, Figure 29)? YES - Proceed to Step 6. NO - Have PCV193 set and confirm it is functioning properly. Replace if needed. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual.

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Diagnostic troubleshooting codes

DTC 34-Low anode supply pressure (continued) Diagnose and troubleshoot DTC 34 (continued)

Figure 29. Fuel system 1.

XV191

HV195

HV183

FV194

PT102

XV101

PCV192 AND PCV193

PT189

NOTE: FL190, PCV192, and PCV193 are all components of the regulator. 6.

Is PCV192 set and properly functioning (Item 4, Figure 29)? YES - Proceed to Step 7. NO - Have PCV192 set and confirm it is functioning properly. Replace if needed. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual.

Is excess flow valve (FV194) stuck closed (Item 6, Figure 29)? YES - Replace FV194. See Replacing FV194 and OR198 in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 8.

Is FL190 clogged? YES - Replace FL190. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 9. 71

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Diagnostic troubleshooting codes

DTC 34-Low anode supply pressure (continued) Diagnose and troubleshoot DTC 34 (continued) 9.

Is adapter (OR198) clogged? YES - Replace OR198. See Replacing FV194 and OR198 in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 10.

10. Have DTC's 95, 18, 19, or 63 recently triggered? YES - Look for possible hydrogen leakage. NO - Proceed to Step 11. 11. If DTC 34 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 35-Minimum cell voltage at start-up Tripping conditions Minimum cell voltage ˂ 700 mV for more than 30 seconds Action Shutdown System fault indicator on HMI is red and blinking Activation states Cathode purge at start-up

Diagnose and troubleshoot DTC 35 1. Check all electrical connections from stack (BoB) to CVM.

Figure 30. CVM connectors 1.

CONN 1

CONN 7

CONN 2

CONN 8

CONN 3

CONN 9

CONN 4

10.

CONN 10

CONN 5

11.

CONN 11

CONN 6

12.

CONN 12

Is more than one cell dropping down? YES - Check that the air compressor and motor drive are functioning properly. DTC's 32, 36, 86, 88, and 89 may indicate an issue with the air compressor. NO - Proceed to Step 3. 73

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Diagnostic troubleshooting codes

DTC 35-Minimum cell voltage at start-up (continued) Diagnose and troubleshoot DTC 35 (continued) NOTE: DTC 32 applies only to fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R. 3.

Have one or more of DTC's 20, 21, 33, 34, and 80 triggered recently?

NOTE: Low cell voltage may be due to anode starvation. Confirm fuel cell is properly fed by hydrogen. YES - Refer to the troubleshooting procedure for the triggered DTC. NO - Proceed to Step 5. 5.

Check F02, K02 functionality and HTR303 resistance. Expected resistance of HTR303 is 9.6Ω. If the value is lower, replace HTR303. If HTR303 is functioning properly, proceed to Step 6.

Figure 31. Heater (HTR303) 1.

CONDENSATE TANK

HEATER

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Diagnostic troubleshooting codes

DTC 35-Minimum cell voltage at start-up (continued) Diagnose and troubleshoot DTC 35 (continued) 6.

Is XV155 functioning properly? YES - Proceed to Step 7. NO - Fix any electrical and mechanical issue needed to make XV155 function properly. Replace if needed. See Replacing drain valve (XV154) and purge valve (XV155) in the Nuvera® Fuel Cell System Service Manual.

Is XV154 functioning properly? YES - Proceed to Step 8. NO - Fix any electrical and mechanical issue needed to make XV154 function properly. Replace if needed. See Replacing drain valve (XV154) and purge valve (XV155) in the Nuvera® Fuel Cell System Service Manual.

Is fuel cell system being fed with proper quality grade hydrogen? YES - Proceed to Step 9. NO - Properly vent the hydrogen tank and refill with proper quality grade hydrogen.

If DTC 35 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 36-Low cathode air flow Tripping conditions Cathode Air Flow ˂ 90% Cathode Air Flow Set-point for more than 30 seconds Action Shutdown System fault indicator on HMI is red and blinking. Activation states Cathode purge at start-up

Diagnose and troubleshoot DTC 36 NOTE: Follow Step 1. through Step 11. if the compressor is NOT running. If the compressor IS running, skip to Step 12. 1.

Have DTC 88 and/or DTC 89 triggered? YES - Follow troubleshooting procedure in DTC 88-Motor controller error status and DTC 89-Motor controller warning status. NO - Proceed to Step 3.

Is the air filter clogged? YES - Clean or remove obstruction from the air filter. Replace if necessary. See Replacing the air filter in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 3.

Is motor controller communicating with the VSM? YES - Proceed to Step 7. NO - Check fuse F06 and contactor K06. Replace if necessary. See the Nuvera® Fuel Cell System Service Manual.

Is the 35-pin connector of the motor controller plugged properly? YES - Proceed to Step 5. NO - Check and fix any electrical issue to the 35-pin connector of the motor controller.

Is CAN bus resistance equal to 120 Ohms? YES - Proceed to Step 6. NO - Check and fix any electrical issue to the CAN bus channel 2.

Is the VSM sending messages on CAN bus channel 2? YES - Proceed to Step 11. NO - Check and fix any electrical issue to the CAN bus channel 2.

Is the voltage from the ultracaps too low? 76

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Diagnostic troubleshooting codes

DTC 36-Low cathode air flow (continued) Diagnose and troubleshoot DTC 36 (continued) YES - Start fuel cell system and wait 15 minutes for ultracapacitors to be recharged. Proceed to Step 8. NO - Proceed to Step 9. 8.

Have ultracapacitors been charged? YES - Proceed to Step 9. NO - Perform the following: • Check battery voltage and recharge if necessary. • Check battery wiring and ultracapacitor wiring.

Has Fuse F05 blown or has relay K3 failed open? YES - Replace fuse F05 and/or relay K03. See the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 10.

10. Is the 48VDC supply applied properly? YES - Proceed to Step 11. NO - Check wiring between ultracapacitors and motor controller. 11. If DTC 36 still triggers, contact Nuvera for assistance. NOTE: Follow steps below if the compressor IS running. 12. Is data from TRICAN sensor properly logged? YES - Proceed to Step 16. NO - Proceed to Step 13. 13. Is CAN bus of channel 1 either faulted or loaded with a large number of errors? YES - Proceed to Step 14. NO - Check if bus is properly terminated. 14. Is CAN bus of channel 1 properly loaded with messages from TRICAN sensor? YES - Proceed to Step 15. NO - Check and fix any electrical issue to the CAN bus channel 1. 15. Is the correct firmware loaded on the motor controller? YES - Proceed to Step 16. NO - Check firmware loaded on motor controller. Update if necessary. 16. If DTC 36 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 38-Minimum cell voltage at shutdown Tripping conditions Minimum cell voltage ˂ 700 mV for more than 1 second Action None Warning logged only Activation states Minimum load at shutdown

Diagnose and troubleshoot DTC 38 1. Is DTC 38 triggering more than once in a 24 hour period? YES - Proceed to Step 2. NO - Return to service. 2.

Check F02, K02 functionality and HTR303 resistance. Expected resistance of HTR303 is 9.6Ω. If the value is lower, replace HTR303. If HTR303 is functioning properly and DTC 38 still triggers, proceed to Step 3.

Figure 32. Heater (HTR303) 1.

CONDENSATE TANK

HEATER

Is DTC 38 still triggering frequently? YES - Proceed to Step 4. 78

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Diagnostic troubleshooting codes

DTC 38-Minimum cell voltage at shutdown (continued) Diagnose and troubleshoot DTC 38 (continued) 4.

Check DC/DC firmware. Update firmware if necessary. If correct firmware is loaded and DTC 38 still triggers, proceed to Step 5.

Check DC/DC hardware and wiring? If DC/DC hardware and wiring is functioning properly and DTC 38 still triggers, proceed to Step 6.

If DTC 38 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 40-Low cell voltage at OCV Tripping conditions Minimum cell voltage < 930 mV for more than 4 seconds Action None Yellow fault notification Activation states Stack Bleed at shutdown

Diagnose and troubleshoot DTC 40 1. Is DTC 9 occurring together with DTC 42? YES - Stack discharge is not confirmed since no communication is established between VSM and CVM. NO - Proceed to Step 2. 2.

Is DTC 40 ocurring frequently? YES - Proceed to Step 3.

Check F02, K02 functionality and HTR303 resistance. Expected resistance of HTR303 is 9.6Ω. If the value is lower, replace HTR303. If HTR303 is functioning properly and DTC 40 still triggers, proceed to Step 4.

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Diagnostic troubleshooting codes

DTC 40-Low cell voltage at OCV (continued) Diagnose and troubleshoot DTC 40 (continued)

Figure 33. Heater (HTR303) 1.

CONDENSATE TANK

HEATER

If DTC 42 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 41-Minimum cell voltage at shutdown Tripping conditions Minimum cell voltage >50 mV for more than 30 seconds Action None Yellow fault notification Activation states Stack Bleed at shutdown

Diagnose and troubleshoot DTC 41 1. Is DTC 41 triggering frequently? YES - Proceed to Step 2. 2.

Check F02, K02 functionality and HTR303 resistance. Expected resistance of HTR303 is 9.6Ω. If the value is lower, replace HTR303. If HTR303 is functioning properly and DTC 41 still triggers, proceed to Step 3.

Figure 34. Heater (HTR303) 1.

CONDENSATE TANK

HEATER

If DTC 41 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 42-High average cell voltage at shutdown Tripping conditions Average cell voltage >100 mV for more than 30 seconds Action None Yellow fault notification Activation states Stack Bleed at shutdown

Diagnose and troubleshoot DTC 42 1. Is DTC 42 triggering frequently? YES - Proceed to Step 2. 2.

Check F02, K02 functionality and HTR303 resistance. Expected resistance of HTR303 is 9.6Ω. If the value is lower, replace HTR303. If HTR303 is functioning properly and DTC 42 still triggers, proceed to Step 3.

Figure 35. Heater (HTR303) 1.

CONDENSATE TANK

HEATER

If DTC 42 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 52-High coolant inlet temperature Tripping conditions Coolant inlet temperature TT304 ˃ coolant inlet temperature setpoint + 5°C for more than 30 seconds Action None Warning logged only Activation states Always

Diagnose and troubleshoot DTC 52 NOTE: Wait 15 minutes for fuel cell system to cool down before trying to restart. 1.

Has DTC 100 triggered also? YES - 5 VDC supply voltage to TT304 from VSM has failed causing a misreading of TT304. See DTC 100-5VDC supply of VSM Faulted or restart fuel cell system. Contact Nuvera if DTC 100 occurs frequently. NO - Proceed to Step 2.

Are any of DTC's 11, 12, 14, or 15 triggering after restarting fuel cell system?

NOTE: Keep note if alarms due to high temperature start triggering at a higher rate. An occasional triggering of the alarm may be due to high ambient temperature. However, if occurrance rate increases, check the functionality of all coolant loop components. YES - Proceed to Step 3. NO - Check the functionality of all coolant loop components: • • • • 3.

Radiator (HX353) Fan (FAN365) Three-way valve Coolant pump (PMP351)

Is NTC expected resistance measurement consistent with room temperature?

Is there enough coolant into fuel cell system?

NOTE: Warning DTC 53 (not shown on HMI but logged into CAN datalogger) may indicate a lack of coolant. 84

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Diagnostic troubleshooting codes

DTC 52-High coolant inlet temperature (continued) Diagnose and troubleshoot DTC 52 (continued) YES - Proceed to Step 5. NO - Refill with Glysantin 50/50 if needed. See Draining and refilling coolant in the Nuvera® Fuel Cell System Service Manual. 5.

Is the radiator HX353 dirty? YES - Clean the radiator by removing any dirt from its surface. NO - Proceed to Step 6.

Is coolant loop leaking? YES - Check for leakage in coolant circuit and replace damaged component if needed. NO - Proceed to Step 7.

Is fan FAN365 functioning properly? Check if: • Fan is still spinning. • Fan is still spinning at desired speed. YES - Proceed to Step 8. NO - Check the following and replace if needed: • Connector V2 on VSM is plugged and properly wired. • Fuse F08 and fan wiring. See Figure 36 or Figure 37. • DPS356 setting and wiring. See Figure 36 or Figure 37.

Is three-way valve functioning properly? YES - Proceed to Step 9. NO - See Replacing the three-way valve in the Nuvera® Fuel Cell System Service Manual.

Is coolant pump PMP351 functioning properly?

NOTE: Warning DTC 53 (not shown on HMI but logged into CAN datalogger) may indicate a lack of coolant. Check if: • Pump is still spinning. • Pump is still spinning at desired speed. YES - Proceed to Step 10. NO - See Figure 36 or Figure 37 below. Check the following and replace if needed: • Connector V2 on VSM is plugged and properly wired • Fuse F06 and contactors K06 and K03 • Wiring between pump and DC/DC converter 85

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Diagnostic troubleshooting codes

DTC 52-High coolant inlet temperature (continued) Diagnose and troubleshoot DTC 52 (continued) • Wiring between batteries and DC/DC converter

Figure 36. Electrical connectors (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) 1.

DC/DC CONNECTOR

BATTERY WIRING

FUSES

DPS WIRING

RELAY (K14)

RELAY (K06)

FAN CONNECTOR

PUMP CONNECTOR

K01

10.

K03

11.

K04

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Diagnostic troubleshooting codes

DTC 52-High coolant inlet temperature (continued) Diagnose and troubleshoot DTC 52 (continued)

Figure 37. Electrical connectors (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) 1.

BATTERY SYSTEM

BATTERY WIRING

FAN CONNECTOR

FUSES

K01

HIGH PRESSURE WIRE HARNESS

10.

K03

11.

K04

FUSE BRACKET

12.

DC-DC CONNECTOR

RELAY (K06)

13.

MAIN WIRE HARNESS

RELAY (K14)

10. If DTC 52 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 53-High coolant delta temperature Tripping conditions Coolant delta temperature TT351 – TT304 > coolant delta temperature + 4°C for more than 30 seconds Action None Warning logged only Activation states Always

Diagnose and troubleshoot DTC 53 NOTE: Wait 15 minutes for fuel cell system to cool down before trying to restart. 1.

Is DTC 52 triggering also? YES - This could indicate the stack has dried out and is producing too much heat. NO - Proceed to Step 2.

Is DTC 53 triggering often? YES - Proceed to Step 3.

Has DTC 100 triggered also? YES - 5 VDC supply voltage to sensor from VSM has failed causing a misreading of sensor. See DTC 100-5VDC supply of VSM Faulted or restart fuel cell system. Contact Nuvera if DTC 100 occurs frequently. NO - Proceed to Step 4.

Is there enough coolant in fuel cell system?

NOTE: Warning DTC 53 (not shown on HMI but logged into CAN datalogger) may indicate a lack of coolant. YES - Proceed to Step 5. NO - Refill with Glysantin 50/50 if needed. See Draining and refilling coolant in the Nuvera® Fuel Cell System Service Manual. 5.

Is coolant pump PMP351 functioning properly? YES - Proceed to Step 8.

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Diagnostic troubleshooting codes

DTC 53-High coolant delta temperature (continued) Diagnose and troubleshoot DTC 53 (continued) NO - See Figure 38 or Figure 39 below. Check the following and replace if needed: • • • •

Connector V2 on VSM is plugged and properly wired Fuse F06 and contactors K06 and K03 Wiring between pump and DC/DC converter Wiring between batteries and DC/DC converter

Figure 38. Electrical connectors (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) 1.

DC/DC CONNECTOR

BATTERY WIRING

FUSES

DPS WIRING

RELAY (K14)

RELAY (K06)

FAN CONNECTOR

PUMP CONNECTOR

K01

10.

K03

11.

K04

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Diagnostic troubleshooting codes

DTC 53-High coolant delta temperature (continued) Diagnose and troubleshoot DTC 53 (continued)

Figure 39. Electrical connectors (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) 1.

BATTERY SYSTEM

BATTERY WIRING

FAN CONNECTOR

FUSES

K01

HIGH PRESSURE WIRE HARNESS

10.

K03

11.

K04

FUSE BRACKET

12.

DC-DC CONNECTOR

RELAY (K06)

13.

MAIN WIRE HARNESS

RELAY (K14)

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Diagnostic troubleshooting codes

DTC 53-High coolant delta temperature (continued) Diagnose and troubleshoot DTC 53 (continued) • Fuse F08 and fan wiring. See Figure 38 or Figure 39. • DPS356 setting and wiring. See Figure 38 or Figure 39. 8.

Is control valve TCV352 functioning properly? YES - Proceed to Step 9. NO - Check the following and replace if needed: • Connector V2 and V3 on VSM are plugged and properly wired. See Figure 40. • Pololu motor drive is plugged and properly wired

Figure 40. VSM Connectors 1.

V1 CONNECTOR

V2 CONNECTOR

V3 CONNECTOR

V4 CONNECTOR

V5 CONNECTOR

If DTC 53 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 54-Low cathode inlet dew-point Tripping conditions Cathode inlet dew-point HT207 ˂ cathode inlet dew-point setpoint > 6°C for 300 seconds Action None Warning logged only Activation states Run State

Diagnose and troubleshoot DTC 54 1. Is DTC 54 triggering often? YES - Proceed to Step 2. 2.

Is FCV252 functioning properly? YES - Proceed to Step 3. NO - Check connectors V2 and V3 on VSM are plugged and properly wired. Check valve opening is consistent. Replace if necessary.

Is FCV252 closed most of the time? YES - Check TRICAN sensor is properly working. Replace if needed. NO - Proceed to Step 4.

Is humidifier functioning properly? YES - Proceed to Step 5. NO - Check that humidifier is not clogged and is functioning properly. Replace if needed.

If DTC 54 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 55-Low cathode inlet pressure Tripping conditions Cathode Inlet Pressure ˂ 20% Cathode Inlet Pressure Set-point for more than 15 seconds Action None Warning logged only Activation states Run State

Diagnose and troubleshoot DTC 55 NOTE: Follow Step 1. through if the compressor is NOT running. If the compressor IS running, skip to Step 6. 1.

Have DTC 88 and/or DTC 89 triggered? YES - Follow troubleshooting procedure in DTC 88-Motor controller error status and DTC 89-Motor controller warning status. NO - Proceed to Step 2.

Is motor controller communicating with the VSM? YES - Proceed to Step 6. NO - Check fuse F06 and contactor K06 (see Figure 41 or Figure 42). Replace if necessary. See the Nuvera® Fuel Cell System Service Manual.

Is the 35-pin connector of the motor controller plugged properly? YES - Proceed to Step 4. NO - Check and fix any electrical issue to the 35-pin connector of the motor controller.

Is CAN bus resistance equal to 120 Ohms? YES - Proceed to Step 5. NO - Check and fix any electrical issue to the CAN bus channel 2.

Is the VSM sending messages on CAN bus channel 2? YES - Proceed to Step 10. NO - Check and fix any electrical issue to the CAN bus channel 2.

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Diagnostic troubleshooting codes

DTC 55-Low cathode inlet pressure (continued) Diagnose and troubleshoot DTC 55 (continued)

Figure 41. Electrical connectors (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) 1.

DC/DC CONNECTOR

BATTERY WIRING

FUSES

DPS WIRING

RELAY (K14)

RELAY (K06)

FAN CONNECTOR

PUMP CONNECTOR

K01

10.

K03

11.

K04

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Diagnostic troubleshooting codes

DTC 55-Low cathode inlet pressure (continued) Diagnose and troubleshoot DTC 55 (continued)

Figure 42. Electrical connectors (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) 1.

BATTERY SYSTEM

BATTERY WIRING

FAN CONNECTOR

FUSES

K01

HIGH PRESSURE WIRE HARNESS

10.

K03

11.

K04

FUSE BRACKET

12.

DC-DC CONNECTOR

RELAY (K06)

13.

MAIN WIRE HARNESS

RELAY (K14)

NOTE: Follow steps below if the compressor IS running. 6.

Is data from TRICAN sensor properly logged? YES - Proceed to Step 10. NO - Proceed to Step 7.

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Diagnostic troubleshooting codes

DTC 55-Low cathode inlet pressure (continued) Diagnose and troubleshoot DTC 55 (continued) 7.

Is CAN bus of channel 1 either faulted or loaded with a large number of errors? YES - Proceed to Step 8. NO - Check if bus is properly terminated.

Is CAN bus of channel 1 properly loaded with messages from TRICAN sensor? YES - Proceed to Step 9. NO - Check and fix any electrical issue to the CAN bus channel 1.

Is the correct firmware loaded on the motor controller? YES - Proceed to Step 10. NO - Check firmware loaded on motor controller. Update if necessary.

10. If DTC 55 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 62-Low anode supply pressure Tripping conditions 50 mbara ˂ PT102 ˂ 7000 mbara for more than 3 seconds Action Shutdown System fault indicator on HMI is red and blinking Activation states From start-up to shutdown

Diagnose and troubleshoot DTC 62 1. Is fuel pump on HMI red and blinking? (DTC 80) YES - Refuel tank. NO - Proceed to Step 2. 2.

Is manual lockdown (HV183) closed? YES - Open HV183. See Figure 43. NO - Proceed to Step 4.

Is solenoid valve (XV101) plugged and properly functioning (Item 7, Figure 43)? YES - Proceed to Step 5. NO - Fix any electrical and mechanical issue necessary to make XV101 function properly. Replace if needed. See Replacing solenoid valve (XV101) in the Nuvera® Fuel Cell System Service Manual.

Is shutoff valve (XV191) plugged and properly functioning (Item 1, Figure 43)? YES - Proceed to Step 6. NO - Fix any electrical and mechanical issue necessary to make XV191 function properly. A replacement may be necessary, however XV191 may not be replaced individually. The entire fuel storage tank must be replaced. Contact Nuvera for assistance.

Is PCV193 set and properly functioning (Item 4, Figure 43)? YES - Proceed to Step 7. NO - Have PCV193 set and confirm it is functioning properly. Replace if needed. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual. 97

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Diagnostic troubleshooting codes

DTC 62-Low anode supply pressure (continued) Diagnose and troubleshoot DTC 62 (continued)

Figure 43. Fuel system 1.

XV191

HV195

HV183

FV194

PT102

XV101

PCV192 AND PCV193

PT189

NOTE: FL190, PCV192, and PCV193 are all components of the regulator. 7.

Is PCV192 set and properly functioning (Item 4, Figure 43)? YES - Proceed to Step 8. NO - Have PCV192 set and confirm it is functioning properly. Replace if needed. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual.

Is excess flow valve (FV194) stuck closed (Item 6, Figure 43)? YES - Replace FV194. See Replacing FV194 and OR198 in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 9.

Is FL190 clogged? YES - Replace FL190. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 10. 98

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Diagnostic troubleshooting codes

DTC 62-Low anode supply pressure (continued) Diagnose and troubleshoot DTC 62 (continued) 10. Is adapter (OR198) clogged? YES - Replace OR198. See Replacing FV194 and OR198 in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 11. 11. Have DTC's 95, 18, 19, or 63 recently triggered? YES - Look for possible hydrogen leakage. NO - Proceed to Step 12. 12. If DTC 62 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 63-High anode supply pressure Tripping conditions PT102 ˃ 14000 mbara for more than 3 seconds (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) PT102 ˃ 15000 mbara for more than 1 second (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) Action Shutdown System fault indicator on HMI is red and blinking Activation states From start-up to shutdown

Diagnose and troubleshoot DTC 63 1. Is PCV193 set and properly functioning (Item 4, Figure 44)? YES - Proceed to Step 2. NO - Have PCV193 set and confirm it is functioning properly. Replace if needed. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual.

100

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Diagnostic troubleshooting codes

DTC 63-High anode supply pressure (continued) Diagnose and troubleshoot DTC 63 (continued)

Figure 44. Fuel system 1.

XV191

HV195

HV183

FV194

PT102

XV101

PCV192 AND PCV193

PT189

Is PCV192 set and properly functioning (Item 4, Figure 44)? YES - Proceed to Step 3. NO - Have PCV192 set and confirm it is functioning properly. Replace if needed. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual.

Is FV194 stuck closed (Item 6, Figure 44)? YES - Replace FV194. See Replacing FV194 and OR198 in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 4.

Is OR198 clogged? YES - Replace OR198. See Replacing FV194 and OR198 in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 5.

Have DTC's 95, 18, 19, or 63 recently triggered? 101

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Diagnostic troubleshooting codes

DTC 63-High anode supply pressure (continued) Diagnose and troubleshoot DTC 63 (continued) YES - Look for possible hydrogen leakage. NO - Proceed to Step 6. 6.

If DTC 63 still triggers, contact Nuvera for assistance.

102

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Diagnostic troubleshooting codes

DTC 71-Not tracking humidifier bypass valve (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) Tripping conditions Valve Position Command-Actual Valve Position > 20% when Valve Position Command > 20% for more than 20 s Action None Fault indicator on HMI is yellow Activation states Always

Diagnose and troubleshoot DTC 71 1. Are V2 and V5 connectors on VSM properly wired? YES - Proceed to Step 2. NO - Make sure that connectors V2 and V5 on VSM are plugged and properly wired. 2.

Is motor drive properly wired? YES - Proceed to Step 3. NO - Make sure that motor drive is properly wired. Replace motor drive if needed.

Is control valve FCV252 properly functioning? YES - Proceed to Step 4. NO - Replace control valve.

If DTC 71 still triggers, contact Nuvera for assistance.

103

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Diagnostic troubleshooting codes

DTC 72-Not tracking radiator bypass valve (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) Tripping conditions Valve Position Command-Actual Valve Position > 20% when Valve Position Command > 20% for more than 20 s Action None Fault indicator on HMI is yellow Activation states Always

Diagnose and troubleshoot DTC 72 1. Are V2 and V5 connectors on VSM properly wired? YES - Proceed to Step 2. NO - Make sure that connectors V2 and V5 on VSM are plugged and properly wired. 2.

Is motor drive properly wired? YES - Proceed to Step 3. NO - Make sure that motor drive is properly wired. Replace motor drive if needed.

Is control valve TCV352 properly functioning? YES - Proceed to Step 4. NO - Replace control valve.

If DTC 72 still triggers, contact Nuvera for assistance.

104

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Diagnostic troubleshooting codes

DTC 75-Very low state of charge Tripping conditions Class I Ultracaps State of Charge less than 48.2456% (corresponding to 33 VDC bus voltage) Class II Ultracaps State of Charge less than 61.4035% (corresponding to 28 VDC bus voltage) Action Shutdown Fault Indicator on HMI red and blinking Activation states Always

Diagnose and troubleshoot DTC 75 1. Is load particularly high? YES - If HMI energy storage indicator is tripped (DTC 98 and/or DTC 99), decrease load to avoid excessive discharge of ultracapacitors. Proceed to Step 2. NO - Check if V5-16 VSM channel is properly tied to Ultracaps positive. Proceed to Step 4. 2.

Is DTC 75 occurring frequently in these cases? YES - Check on logged file that voltage and current measurement at DC/DC converter inlet and outlet are consistent.

Is DTC 75 occurring frequently? YES - Check if V5-16 VSM channel is properly tied to Ultracaps positive. Proceed to Step 5.

Is DTC 75 occurring frequently? YES - Check connections on ultracapacitors module to find out any source of increased resistance that may jeopardize ultracapacitors charging capability. Proceed to Step 5.

Is DTC 75 occurring frequently?

NOTE: An older fuel cell must operate at a higher current to provide the same amount of energy. Depending on environment conditions, high fuel-cell current can’t be sustained for extended time without drying out fuel cell membranes. A dried-out fuel-cell may behave as if it is older than it actually is. Fuel cell membranes may also flood, in which case recovery time is needed to allow for a higher chance of stack performance recovery. YES - Check that fuel-cell performance isn’t so low that it can’t guarantee enough power to charge ultracaps. Perform hydration/conditioning (dried-out membranes) or purging/conditioning (flooded membranes) procedures to recover fuel-cell performance; if recovering isn’t effective enough to limit DTC 75 occurrences, replace the fuelcell stack. 6.

If DTC 75 still triggers, contact Nuvera for assistance.

105

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Diagnostic troubleshooting codes

DTC 76-Air inlet temperature out of range Tripping conditions Air temperature TT203 ˂ 0°C for more than 1 second Action None System fault indicator on HMI yellow Activation states Always

Diagnose and troubleshoot DTC 76 1. Is fuel cell being operated in freezing conditions? YES - Fuel cell system is not rated for use in freezing conditions. If operating in a freezer, move lift truck to a warmer location. NO - Proceed to Step 2. 2.

Is FT204 connector plugged? YES - Proceed to Step 3. NO - Plug FT204 connector.

Are one or more of DTCs 1, 3, 5, 6, and 7 triggering? YES - Check V3 connector of VSM is plugged and properly wired (Item 3, Figure 45). If proper connection of wiring is confirmed and DTC 76 still triggers, proceed to Step 4. NO - Proceed to Step 4.

Is DTC 76 still triggering? YES - Check wiring between TT203 and VSM. If DTC 76 still triggers, proceed to Step 5. NO - Fix wiring connection. Proceed to Step 5.

Is NTC expected resistance measurement consistent with room temperature? Check NTC resistance measurement. See Table 2. YES - If NTC expected resistance measurement is found to be consistent with room temperature and DTC 76 still triggers, proceed to Step 6. NO - Replace FT204.

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Diagnostic troubleshooting codes

DTC 76-Air inlet temperature out of range (continued) Diagnose and troubleshoot DTC 76 (continued)

Figure 45. VSM Connectors 1.

V1 CONNECTOR

V2 CONNECTOR

V3 CONNECTOR

V4 CONNECTOR

V5 CONNECTOR

If DTC 76 still triggers, Contact Nuvera for assistance.

107

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Diagnostic troubleshooting codes

DTC 77-High air inlet temperature Tripping conditions Air temperature TT203 ˃ 100°C for more than 1 second Action None System fault indicator on HMI is yellow Activation states Always

Diagnose and troubleshoot DTC 77 NOTE: Wait 15 minutes for fuel cell system to cool down before trying to restart. 1.

Has DTC 100 triggered also? YES - 5 VDC supply voltage to TT304 from VSM has failed causing a misreading of TT203. See DTC 100-5VDC supply of VSM Faulted or restart fuel cell system. Contact Nuvera if DTC 100 occurs frequently. NO - Proceed to Step 2.

Is NTC expected resistance measurement consistent with room temperature?

NOTE: Check NTC expected resistance measurement. See Table 2. YES - If NTC expected resistance measurement is found to be consistent with room temperature, and DTC 77 still triggers, proceed to Step 3. NO - Replace FT204. 3.

Is the air cooler HX202 dirty? YES - Clean the radiator by removing any dirt from its surface. NO - Proceed to Step 4.

Is the air cooler HX202 leaking? YES - Check for leakage in radiator and replace if needed. See Removing and installing the radiator in the Nuvera® Fuel Cell System Service Manual. NO - Proceed to Step 5.

Are fans FAN354 functioning properly? YES - Proceed to Step 6. NO - Check the following and replace if needed: • Connector V2 on VSM is plugged and properly wired. See Figure 46. • Fuse F07 and fan wiring

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Diagnostic troubleshooting codes

DTC 77-High air inlet temperature (continued) Diagnose and troubleshoot DTC 77 (continued)

Figure 46. VSM Connectors 1.

V1 CONNECTOR

V2 CONNECTOR

V3 CONNECTOR

V4 CONNECTOR

V5 CONNECTOR

If DTC 77 still triggers, contact Nuvera for assistance.

109

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Diagnostic troubleshooting codes

DTC 78-Ultracapacitors current out of range Tripping conditions Ultracaps current ˂ -800 Amp for more than 1 second Action Shutdown System fault indicator on HMI is red and blinking Activation states Always

Diagnose and troubleshoot DTC 78 1. Has DTC 100 triggered also? YES - 5 VDC supply voltage to sensor from VSM has failed causing a misreading of PT102. See DTC 100-5VDC supply of VSM Faulted or restart fuel cell system and contact Nuvera if DTC 100 occurs frequently. NO - Proceed to Step 2. 2.

Is CS02 plugged? YES - Proceed to Step 3. NO - Plug current sensor.

Is CS02 wired properly? YES - Proceed to Step 4. NO - Fix any electrical and mechanical issue necessary to make CS02 function properly. Replace if needed.

If DTC 78 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 79-H2 tank pressure out of range Tripping conditions H2 tank pressure PT189 out of 0-413 bara for more than 1 second Action None System fault indicator on HMI is yellow Activation states Always

Diagnose and troubleshoot DTC 79 1. Is PT189 connector plugged? YES - Proceed to Step 2. NO - Plug PT189 connector. 2.

Are one or more of DTCs 1, 3, 6, and 7 triggering? YES - Check V3 connector of VSM is plugged and properly wired. If proper connection of wiring is confirmed and DTC 79 still triggers, proceed to Step 3. NO - Proceed to Step 3.

Check wiring between PT189 and VSM. If wiring is properly connected and DTC 79 still triggers, proceed to Step 4.

Check 24VDC supply to sensor. If DTC 79 still triggers, proceed to Step 5.

Replace PT189 sensor. If DTC 79 still triggers, proceed to Step 6.

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DTC 79-H2 tank pressure out of range (continued) Diagnose and troubleshoot DTC 79 (continued)

Figure 47. VSM Connectors 1.

V1 CONNECTOR

V2 CONNECTOR

V3 CONNECTOR

V4 CONNECTOR

V5 CONNECTOR

If DTC 79 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 80-Low H2 tank pressure Tripping conditions 0 bara ˂ PT189 ˂ 30 bara for more than 5 seconds Action Shutdown System fault indicator on HMI is red and blinking Activation states Always

Diagnose and troubleshoot DTC 80 1. Refuel tank. If DTC 80 still triggers, proceed to Step 2. 2.

Is PT189 wired properly? YES - Proceed to Step 3. NO - Fix any electrical issue necessary to make PT189 function properly. Replace if needed.

If DTC 80 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 81-Low H2 tank pressure Tripping conditions 0 bara ˂ PT189 ˂ 65 bara for more than 10 seconds Action None Fuel indicator on HMI is red and blinking Activation states Always

Diagnose and troubleshoot DTC 81 1. Refuel tank. If DTC 81 still triggers, proceed to Step 2. 2.

Is PT189 wired properly? YES - Proceed to Step 3. NO - Fix any electrical issue necessary to make PT189 function properly. Replace if needed.

If DTC 81 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 82-Low H2 tank pressure Tripping conditions 0 bara ˂ PT189 ˂ 95 bara for more than 10 seconds Action None Fuel indicator on HMI is yellow Activation states Always

Diagnose and troubleshoot DTC 82 1. Refuel tank. If DTC 82 still triggers, proceed to Step 2. 2.

Is PT189 wired properly? YES - Proceed to Step 3. NO - Fix any electrical issue necessary to make PT189 function properly. Replace if needed.

If DTC 82 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 84-High water tank level Tripping conditions Water level HLS259 ˃ 20% for more than 30 seconds Action None Dewater indicator on HMI is yellow Activation states Always

Diagnose and troubleshoot DTC 84 NOTE: DTC 84 triggers when water tank level is high and will require dewatering soon. 1.

Dewater tank. If DTC 84 still triggers, proceed to Step 2.

Is HLS259 wired properly? YES - Proceed to Step 3. NO - Fix any electrical issue necessary to make HLS259 function properly. Replace if needed.

If DTC 84 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 85-High water tank level Tripping conditions Water level HLS259 ˃ 45% for more than 30 seconds Action None Dewater indicator on HMI is red and blinking Activation states Always

Diagnose and troubleshoot DTC 85 NOTE: DTC 85 triggers when water tank level is extremely high. Dewater immediately. 1.

Dewater tank. If DTC 85 still triggers, proceed to Step 2.

Is HLS259 wired properly? YES - Proceed to Step 3. NO - Fix any electrical issue necessary to make HLS259 function properly. Replace HLS259 if needed.

If DTC 85 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 86-Low motor controller speed Tripping conditions Motor Controller Speed Command – Motor Controller Actual Speed > 20% of Motor Controller Speed Command when Motor Controller Speed Command > 1000 RPM for more than 10 seconds Action None Warning logged only Activation states From start-up to shutdown

Diagnose and troubleshoot DTC 86 1. Is DTC 89 triggering also? YES - Proceed to Step 2. NO - Check that proper wiring is established between VSM and motor controller. 2.

Check motor controller error code on data logged (MotCtrlErrCode_ToHost).

If DTC 86 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 88-Motor controller error status Tripping conditions Motor controller error status triggers for more than 2 seconds Action Shutdown System fault indicator on HMI is red and blinking Activation states From start-up to shutdown

Diagnose and troubleshoot DTC 88 1. Check motor controller error code on data logged (MotCtrlErrCode_ToHost). 2.

If DTC 88 still triggers, contact Nuvera for assistance.

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DTC 89-Motor controller warning status Tripping conditions Motor controller warning status triggers for more than 100 ms Action None Warning logged only Activation states From start-up to shutdown

Diagnose and troubleshoot DTC 89 1. Check motor controller error code on data logged (MotCtrlErrCode_ToHost). 2.

If DTC 89 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 90-DC/DC Loss of communication Tripping conditions DC/DC not communicating for more than 3 seconds Action Shutdown Fault indicator on HMI is red and blinking Activation states Always

Diagnose and troubleshoot DTC 90 1. Is DC/DC CAN connector plugged? YES - Proceed to Step 2. NO - Plug DC/DC connector (P010/J010). 2.

Is power provided to DC/DC? YES - Proceed to Step 3. NO - Check that start-up batteries are charged. Check safety circuit and contactor K07. Check wiring on DC/DC (P010/J010 connector).

Is CAN bus of channel 2 either faulted or loaded with a large number of errors?

NOTE: Since channel 2 has the two 120 Ω termination resistance on DC/DC and on CAN2_RES connector, 60 Ω should be read at VSM level (between VSM_V4_5 and VSM_V4_6 pins) YES - Check bus is properly terminated. NO - Proceed to Step 4. 4.

Is CAN bus of channel 2 still either faulted or loaded with a large number of errors? YES - Proceed to Step 5. NO - Check wiring of all components on CAN bus of channel 2 (VSM, DC/DC and air compressor motor controller).

Is proper firmware loaded on DC/DC? NO - Check DC/DC loaded firmware version and update if needed. YES - Proceed to Step 6.

Are CAN bus of channel 2 properly loaded with messages from air compressor motor controller? YES - Proceed to Step 7.

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DTC 90-DC/DC Loss of communication (continued) Diagnose and troubleshoot DTC 90 (continued) NO - Alternatively disconnect DC/DC and motor controller from CAN bus to determine which among the 2 (or both) needs to be replaced. 7.

If DTC 90 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 91-DC/DC error status Tripping conditions DC/DC error status triggers for more than 1 second Action Shutdown System fault indicator on HMI is red and blinking Activation states Always

Diagnose and troubleshoot DTC 91 1. Check DC/DC error code on data logged (DcdcFltCode_ToHost). 2.

Inspect all pins in connector. Confirm connector is fully seated.

If DTC 91 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 92-DC/DC warning status Tripping conditions DC/DC error warning triggers for more than 100 ms Action None Warning logged only Activation states Always

Diagnose and troubleshoot DTC 92 1. Check DC/DC error code on data logged (DcdcFltCode_ToHost). 2.

If DTC 92 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 94-Fuel cell back current Tripping conditions Fuel cell_Voltage_Bus_Voltage ˂ 2V for more than 100 ms Action Immediate shutdown of fuel cell System fault indicator on HMI is red and blinking Activation states From RUN state through Shutdown

Diagnose and troubleshoot DTC 94 1. Are ultracapacitors charged? YES - Proceed to Step 3. NO - Start fuel cell system and wait 15 minutes for ultracapacitors to be recharged. Proceed to Step 2. 2.

Have ultracapacitors been charged? YES - Proceed to Step 3. NO - Perform the following checks: • Check battery voltage and recharge if needed. • Check battery and ultracapacitors wiring.

Is bus voltage above 65 VDC?

NOTE: Energy storage indicator on HMI should be either yellow or red and blinking (DTC 98 and 99). Stand-by logic may be disabled/prevented in the software version used. Without it, in case the HMI notifies high ultracaps state-of-charge, an increase in power request from truck is recommended to avoid truck shut-down (DTC 96). 4.

Is truck draining power from fuel cell system? YES - Proceed to Step 5. NO - Check contactor K04 and K03.

Is CVM functioning properly? YES - Proceed Step 6. NO - Check CVM functionality and wiring (from BoB to CVM). Replace if needed.

Are one or more of DTC's 25, 26, and 27 triggering? YES - Refer to instructions for DTC being triggered. NO - Proceed to Step 7.

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Diagnostic troubleshooting codes

DTC 94-Fuel cell back current (continued) Diagnose and troubleshoot DTC 94 (continued) 7.

If DTC 94 is still triggering, perform the following checks: • Check if DTC 91 or DTC 92 are triggering also. This may indicate a failure in the DC/DC converter. • Check DC/DC loaded firmware. Updated if needed. • Check DC/DC hardware and wiring.

If DTC 94 is still triggering, Contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 95-Anode over-pressure Tripping conditions Pressure switch PS104 tripped for more than 100 ms Action Immediate shutdown of fuel cell system System fault indicator on HMI is red and blinking Activation states Always

Diagnose and troubleshoot DTC 95 1. Is either DTC 18 or 19 triggering also? YES - Proceed to Step 2. NO - Check if PS104 is correctly wired and functioning properly. Replace if necessary. 2.

Has DTC 63 triggered also? YES - Proceed to Step 3. NO - Proceed to Step 5.

Is PCV193 set and properly functioning? YES - Proceed to Step 4. NO - Have PCV193 set and confirm it is functioning properly. Replace if needed. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual.

Is PCV192 set and properly functioning? YES - Proceed to Step 5. NO - Have PCV192 set and confirm it is functioning properly. Replace if needed. See Replacing FL190, PCV192 and PCV193 in the Nuvera® Fuel Cell System Service Manual.

Is FV194 functioning properly? YES - Proceed to Step 6. NO - Replace FV194. See Replacing FV194 and OR198 in the Nuvera® Fuel Cell System Service Manual.

Is OR198 installed properly? YES - Proceed to Step 7. NO - Properly install OR198. Replace if necessary. See Replacing FV194 and OR198 in the Nuvera® Fuel Cell System Service Manual.

Has DTC 22 triggered? YES - Make sure no occlusion on cathode side is in place and perform the following checks: 127

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DTC 95-Anode over-pressure (continued) Diagnose and troubleshoot DTC 95 (continued) • Check exhaust hose is not clogged and/or pinched • Check condensate tank exit is not clogged • Check CV251 is correctly mounted and is functioning properly • Check humidifier (wet and dry sides) is not clogged and gaskets are properly in place • Check fuel-cell is not clogged and gaskets are properly in place • Check cathode cooler HX202 is not clogged NO - Proceed to Step 8. 8.

Is ejector assembly PCE103 functioning properly? YES - Proceed to Step 9. NO - Check that ejector is properly working. Replace if necessary.

If DTC 95 is still triggering, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 96-High state of charge Tripping conditions Ultracaps state of charge ˃ 97% for more than 1 second for class I fuel cell Ultracaps state of charge ˃ 98.6% for more than 1 second for class II fuel cell Action Shutdown System fault indicator on HMI is red and blinking Activation states RUN

Diagnose and troubleshoot DTC 96 1. Check logged file to confirm that voltage and current measurement at DC/DC converter inlet and outlet are consistent. 2.

Is there a loose connection on the top plate of the ultracaps module? YES - Fix loose connection. NO - Proceed to Step 3.

Are any other connections loose? YES - Fix loose connection. NO - Proceed to Step 4.

Restart fuel cell system. • Ultracaps voltage is greater than 65 VDC, but would decrease before closing the truck contactor once fuel cell system is restarted.

If DTC 96 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 97-System switch-off relay Tripping conditions System switch-off relay is open for more than 1 second Action None System fault indicator on HMI is red and blinking (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) Logged Warning (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) Activation states Off and fault

Diagnose and troubleshoot DTC 97 1. Check if K07 has failed. Replace if needed, or risk losing the ability to cut the power in case the safety circuit trips a safety relevant fault. 2.

Visually inspect all pins. Confirm pins are fully seated in the fuse box.

If DTC 97 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 98-Low/High state of charge Tripping conditions Ultracaps state of charge out of 92% range for more than 1 second for class I fuel cell Ultracaps state of charge out of 63.6-97.6% range for more than 1 second for class II fuel cell Action None Energy storage indicator on HMI is red and blinking Activation states RUN

Diagnose and troubleshoot DTC 98 1. Is load unusually high? YES - Decrease the load to avoid excessive discharge of ultracapacitors. If DTC 98 still triggers after the load is decreased, proceed to Step 2. NO - Shutdown the truck. 2.

Check logged file to confirm that voltage and current measurement at DC/DC converter inlet and outlet are consistent. If DTC 98 still triggers, proceed to Step 3.

Confirm V5-16 VSM channel is properly tied to ultracaps positive.

If DTC 98 still triggers, Contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 99-Low/High state of charge Tripping conditions Ultracaps state of charge out of 68-89% range for more than 3 seconds for class I fuel cell Ultracaps state of charge out of 65.8-95.4% range for more than 3 seconds for class II fuel cell Action None Energy storage indicator on HMI is yellow Activation states RUN

Diagnose and troubleshoot DTC 99 1. Is load unusually high? YES - Decrease the load to avoid excessive discharge of ultracapacitors. If DTC 99 still triggers after the load is decreased, proceed to Step 2. NO - Shutdown the truck. 2.

Check logged file to confirm that voltage and current measurement at DC/DC converter inlet and outlet are consistent. If DTC 99 still triggers, proceed to Step 3.

Confirm V5-16 VSM channel is properly tied to ultracaps positive.

If DTC 99 still triggers, Contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 100-5VDC supply of VSM Faulted Tripping conditions 5VDC_VSM_Supply_Voltage out of 4-6 VDC range for more than 1 second Action None Warning logged only Activation states Always

Diagnose and troubleshoot DTC 100 NOTE: 5 VDC supply from VSM is used to supply most of the sensors in the fuel cell. If fault occurs, measurements may be erratic. 1.

Restart fuel cell system If DTC 100 still triggers, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 101-12VDC supply of VSM faulted Tripping conditions 12VDC_VSM_Supply_Voltage out of 10-14 VDC range for more than 1 second Action None Warning logged only Activation states Always

Diagnose and troubleshoot DTC 101 NOTE: 12 VDC supply from VSM is not being used. 1.

Restart fuel cell system If DTC 101 is still triggering, contact Nuvera for assistance.

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DTC 102-Stand-by mode timed out Tripping conditions Stand-by timer > 1200 seconds Action Shutdown Fault Indicator on HMI red and blinking Activation states Run

Diagnose and troubleshoot DTC 102 NOTE: Lift truck is requiring a very low power for a prolonged period of time. In order to not jeopardize the lifetime of the fuel-cell, the fuel cell will perform a normal shut-down procedure. 1.

Restart fuel cell system If DTC 102 is still triggering, contact Nuvera for assistance.

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Diagnostic troubleshooting codes

DTC 103-EWS loss of integrity (fuel cell systems S/N A2D1S01500R or S/N A2D2S01500R and after) Tripping conditions EWS integrity signal false for more than 1 second Action Shutdown Fault indicator on HMI is red and blinking Activation states Always

Diagnose and troubleshoot DTC 103 1. Is the truck meant to provide EWS integrity signal? YES - Communication between truck and BBR has interrupted. Check that proper EWS integrity signal is provided by truck. NO - Check the jumper to confirm integrity signal is in place and properly wired. Check the wiring between jumper and VSM. 2.

If DTC 103 still triggers, Contact Nuvera for assistance.

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Tables Table 1. Expected resistance measurement 15°C → approx 14600-15250 Ω 20°C → approx 11900-12450 Ω 25°C → approx 9800-10200 Ω 30°C → approx 8100-8450 Ω 35°C → approx 6850-7050 Ω Table 2. Expected resistance measurement 20°C → approx 2300-2550 Ω 30°C → approx 1600-1750 Ω

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Diagnostic troubleshooting codes

Fault code quick reference Table 3. Alarms list Alarms list Code

Variable

Value

Unit

Times

Alarm type

Cooling Inlet < Temperature

°C

Minor

Shutdown

Cooling Inlet > Temperature

100

°C

Minor

Shutdown

Cooling Outlet < Temperature

°C

Minor

Shutdown

Cooling Outlet > Temperature

100

°C

Minor

Shutdown

Anode Supply Pressure

mbara

Yellow Warning Fault Notification

Anode Outlet < Pressure

mbara

Warning

Yellow Fault Notification

Stack Current <

-50

Amp

Minor

Shutdown

CVM Communicati > on

Minor

Shutdown

9**

CVM Communicati > on

Minor

Shutdown

Cooling Inlet > Temperature

°C

Minor

Shutdown

Cooling Inlet > Temperature

°C

Warning

Yellow Fault Notification

Cooling Outlet > Temperature

°C

Minor

Shutdown

138

HMI notification

Activation states

See Table 4.

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Diagnostic troubleshooting codes

Fault code quick reference (continued) Table 3. Alarms list (Continued) Alarms list Code

Variable

Cooling Outlet > Temperature

Value

Unit

°C

Times

Alarm type

HMI notification

Red Coolant Warning Temperatur e Notification

Cooling Outlet > Temperature

°C

Yellow Coolant Warning Temperatur e Notification

Cooling Inlet > Temperature

°C

Warning

Yellow Fault Notification

Anode Outlet > Pressure

3000

mbara

0.5

Warning

Red Fault Notification

Anode Outlet > Pressure

mbara

Yellow Warning Fault Notification

Anode Outlet < Pressure >

1300

mbara

0.5

Major

Immediate Shutdown

Anode Outlet < Pressure >

1350

mbara

Minor

Shutdown

Cathode Inlet > Pressure

1800

mbara

Warning

Yellow Fault Notification

Minimum < Cell voltage

0.25

Major

Immediate Shutdown

Minimum < Cell voltage

300

Minor

Shutdown

Minimum < Cell voltage

Yellow Warning Fault Notification

2500

50 50

400

139

Activation states

See Table 4.

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Diagnostic troubleshooting codes

Fault code quick reference (continued) Table 3. Alarms list (Continued) Alarms list Code

Variable

Value

Unit

Times

Alarm type

Stack Bypass < Air Flow

Minor

Shutdown

Anode Outlet < Pressure >

1500

mbara

Minor

Shutdown

Anode Supply Pressure

7000

mbara

Minor

Shutdown

Minimum < Cell voltage

700

Minor

Shutdown

Cathode Air < Flow

Minor

Shutdown

Minimum < Cell voltage

700

Warning

Logged Warning

Minimum > Cell voltage

Warning

Logged Warning

Average Cell > voltage

100

Warning

Logged Warning

Cooling Inlet Temperature > (Act - Sp)

°C

Warning

Logged Warning

Cooling Delta Temperature > (Act - Sp)

°C

Warning

Logged Warning

Cathode Inlet Dewpoint (Sp > - Act)

°C

300

Warning

Logged Warning

Cathode Inlet Pressure (Sp > - Act)

Warning

Logged Warning

Anode Supply Pressure

mbara

Minor

Shutdown

7000

140

HMI notification

Activation states

See Table 4.

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Diagnostic troubleshooting codes

Fault code quick reference (continued) Table 3. Alarms list (Continued) Alarms list Value

Unit

Times

Alarm type

14000

mbara

Minor

Yellow Warning Fault Notification

°C

Yellow Warning Fault Notification

-800

Amp

Minor

bara

413

bara

Yellow Warning Fault Notification

MInor

Red Fuel Warning Level Notification

bara

Yellow Fuel Warning Level Notification

Warning

Yellow Dewater Notification

Warning

Red Dewater Notification

% 10

Warning

Logged Warning

Code

Variable

Anode Supply Pressure

Air Inlet < Temperature

Air Inlet > Temperature

100

Ultracaps Current

< H2 Pressure Tank >

H2 Pressure < Tank >

< H2 Pressure Tank >

Water Tank > Level

Air > Compressor Speed > Command

0 0

1000

°C

bara bara

RPM

141

HMI notification Shutdown

Activation states

Shutdown

See Table 4

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Diagnostic troubleshooting codes

Fault code quick reference (continued) Table 3. Alarms list (Continued) Alarms list Code

Variable

Value

Unit

Times

Alarm type

HMI notification

Air Compressor = Status

ERROR

Minor

Shutdown

Air Compressor = Status

WARNING

0.1

Warning

Logged Warning

DC/DC Communicati > on

Minor

Shutdown

DC/DC Status =

ERROR

Minor

Shutdown

DC/DC Status =

WARNING

0.1

Warning

Logged Warning

Stack/ Ultracaps Voltage Difference

0.1

Major

Immediate Shutdown

Pressure Switch

True

0.1

Major

Immediate Shutdown

96*

State of Charge

Minor

Shutdown

96**

State of Charge

98.6

Minor

Shutdown

Kswoff

True

Warning

Red Fault Notification

98*

State of Charge

Warning

Red Energy Storage Notification

Red Energy Warning Storage Notification

98**

State of Charge

OR <

97.6

OR <

59.2

142

Activation states

See Table 4.

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Diagnostic troubleshooting codes

Fault code quick reference (continued) Table 3. Alarms list (Continued) Alarms list Code

Variable

99*

State of Charge

99**

100

101

102

Value

Unit

Times

State of Charge

95.4

VSM 5V Supply

65.8

V OR

VSM 12V Supply Stand-by mode

V OR

True

Alarm type

HMI notification

Yellow Energy Warning Storage Notification

Warning

Logged Warning

Warning

Logged Warning

Minor

Shutdown

Activation states

See Table 4

* Class I FCS only (C95A-33) ** Class II FCS only (N95A-21) Legend Immediate Shutdown System will shutdown immediately. Red Fault Notification

A fault has occurred requiring the fuel cell system to be shutdown.

Shutdown

System will begin normal shutdown process.

Yellow Fault Notification

A fault has occurred. The fuel cell system is still operational but requires service.

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Diagnostic troubleshooting codes

Fault code quick reference (continued) Red Coolant Temperature Notification

Temperature has risen above operational threshold.

Yellow Coolant Temperature Notification

Temperature has risen above recommended level.

Red Fuel Level Notification

Immediate refueling is necessary and system shutdown is imminent.

Yellow Fuel Level Notification

Fuel level has dropped below recommended level.

Red Dewater Notification

Water level has risen above operational threshold

Yellow Dewater Notification

Water level has risen above recommended level.

Red Energy Storage Notification

The energy storage system state of charge is outside the operational threshold and a system shutdown is imminent.

Yellow Energy Storage Notification

Fuel cell system is being used beyond its continuous power rating, and energy storage system is outside the recommended state of charge.

Logged Warning

Warning has been logged. No change to system operation.

144

See Navigating the system status screen in the Human Machine Interface (HMI) section of the Nuvera® Nuvera Fuel Cell System Operating Manual, for more information.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Diagnostic troubleshooting codes

Fault code quick reference (continued) Table 4. Activation states Activation states* Code

OFF

START-UP

RUN

SHUT-DOWN

Procedure

17 18 19 20

DTC 1-Coolant inlet temperature out of range

DTC 2-Coolant inlet temperature out of range

DTC 3-Coolant outlet temperature out of range

DTC 4-Coolant outlet temperature out of range

DTC 5-Anode supply pressure out of range

DTC 6-Anode outlet pressure out of range

DTC 7-Fuel cell stack current out of range

DTC 9-CVM loss of communication

DTC 11-High coolant inlet temperature

DTC 12-High coolant inlet temperature

DTC 14-High coolant outlet temperature

DTC 15-High coolant outlet temperature

DTC 16-High coolant outlet temperature

DTC 17-High cathode inlet temperature

DTC 18-High anode outlet pressure

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Diagnostic troubleshooting codes

Fault code quick reference (continued) Table 4. Activation states (Continued) Activation states* Code

OFF

START-UP

RUN

SHUT-DOWN

Procedure

17 18 19 20

DTC 19-High anode outlet pressure

DTC 20-Low anode outlet pressure

DTC 21-Low anode outlet pressure

N N Y

DTC 22-High cathode inlet pressure

N N N

DTC 25-Minimum cell voltage

N N N

DTC 26-Minimum cell voltage

N N N

DTC 27-Minimum cell voltage

N N N

DTC 32-Low stack bypass airflow (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R)

N N N

DTC 33-Low anode outlet pressure at start-up

N N N

DTC 34-Low anode supply pressure

N N N

DTC 35-Minimum cell voltage at start-up

N N Y

DTC 36-Low cathode air flow

N N N

DTC 38-Minimum cell voltage at shutdown

N N N

DTC 41-Minimum cell voltage at shutdown

N N N

DTC 42-High average cell voltage at shutdown

DTC 52-High coolant inlet temperature

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Diagnostic troubleshooting codes

Fault code quick reference (continued) Table 4. Activation states (Continued) Activation states* Code

OFF

START-UP

RUN

SHUT-DOWN

Procedure

17 18 19 20

DTC 53-High coolant delta temperature

N N N

DTC 54-Low cathode inlet dewpoint

N N N

DTC 55-Low cathode inlet pressure

DTC 62-Low anode supply pressure

DTC 63-High anode supply pressure

DTC 76-Air inlet temperature out of range

DTC 77-High air inlet temperature

DTC 78-Ultracapacitors current out of range

DTC 79-H2 tank pressure out of range

DTC 80-Low H2 tank pressure

DTC 81-Low H2 tank pressure

DTC 82-Low H2 tank pressure

DTC 84-High water tank level

DTC 85-High water tank level

DTC 86-Low motor controller speed

DTC 88-Motor controller error status

DTC 89-Motor controller warning status

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Diagnostic troubleshooting codes

Fault code quick reference (continued) Table 4. Activation states (Continued) Activation states* Code

OFF

START-UP

RUN

SHUT-DOWN

Procedure

17 18 19 20

DTC 90-DC/DC Loss of communication

DTC 91-DC/DC error status

DTC 92-DC/DC warning status

N N N

DTC 94-Fuel cell back current

DTC 95-Anode over-pressure

N N N

DTC 96-High state of charge

N N N

DTC 97-System switch-off relay

DTC 98-Low/High state of charge

DTC 99-Low/High state of charge

100

DTC 100-5VDC supply of VSM Faulted

101

DTC 101-12VDC supply of VSM faulted

102

DTC 102-Stand-by mode timed out

* For more information on activation states, see Nuvera® Fuel Cell System operating state flow logic

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Principles of operation

Nuvera® Fuel Cell System operating state flow logic State Name

st fcs Enumeration

PreStart

Ready

Faults

Off

Anode Start

Dilution Start

Anode Purge

Bleed Connect

Cathode Purge

Run

Min Load

Anode Purge Shutdown

Stack Dry Out

Stack Bleed

Stack Discharged

PreStart The VSM will begin in the PreStart state (st_fcs=0), then will progress to Ready state (st_fcs=1) after a delay of 0.2 seconds. Ready In the Ready state, a startup check is performed to ensure no fault is present. This check is to confirm that all sensors are reading properly and no issues are detected with the fuel cell stack. After 1 second, the system will progress to Off state (st_fcs = 2). Off In Off state, another check is performed to ensure that no faults were detected while in Ready state and Start command is still present (Stop button on HMI is not being pressed). a.

If no fault was detected and Start command is still present, the system will wait an additional 3 seconds to confirm the ultracapacitors are properly charged (>65% for Class I, >70% for Class II). • If the ultracapacitors are charged, the system will then progress to operating states, beginning with Anode Start. • If the ultracapacitors are not charged, power is recharged from the 24V battery system until the necessary threshold is met.

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Off (continued) b. If a fault has been detected, the system will remain in Off state for a total of 12 seconds before triggering Kswoff to shut down and de-energize the system. A DTC code is logged to identify the problem. Anode Start In Anode Start state (st_fcs = 16), the H2 tank solenoid valves (XV191) and the stack inlet solenoid valve (XV101) are commanded to open. The system will then confirm that hydrogen is flowing properly by confirming PT102 > 7000mbara and PT157 > 1500mbara, before progressing to Dilution Start state. a.

If PT102 does not reach 7000mbara within 20 seconds after entering this state, the system will shut down and log a code for DTC 34.

If PT157 does not reach 1500mbara within 20 seconds after entering this state, the system will shut down and log a code for DTC 33.

NOTE: To protect the stack from over-pressurization in the event of an ejector failure, the solenoid valves will close to shutoff the hydrogen supply if PT157 exceeds 2200mbara. If PT157 falls below 2000mbara, the valves are opened. Dilution Start In Dilution Start state (st_fcs = 17), the system will continue supplying hydrogen to the stack. The stack bypass valve (FCV205) will open and run the air compressor to achieve a 500SLPM flow rate. After a minimum of 1 second has passed, and the measured RPM feedback signal confirms the compressor is running at >90% of its commanded speed, The system will progress to the next state. a.

If the measured RPM does not reach >90% of its commanded speed within 10 seconds, the system will shut down and log a code for DTC 32.

The RPM setpoint required to achieve the 500SLPM flow rate is not hard-set, but rather is based on a performance “map” and will vary depending on the cathode pressure reading from PT209.

NOTE: To protect the stack from over-pressurization in the event of an ejector failure, the solenoid valves will close to shutoff the hydrogen supply if PT157 exceeds 2200mbara. If PT157 falls below 2000mbara, the valves are opened. Anode Purge In the Anode Purge (st_fcs= 18) state, the code opens the Anode Drain (XV154) and Anode Purge (XV155) solenoid valves to eliminate any nitrogen concentration that may have built up on the anode catalyst layer. Once the nitrogen concentration has been reduced below the required threshold (25%, or 0.25 in the system data logs), the system will progress to Bleed Connect state. The time required for this step is dictated by a calculation performed onboard the VSM that determines how much nitrogen is present. A 55% concentration is typical at each start up, therefore the timing should be consistent and approximately in the 5 second range.

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Principles of operation

Bleed Connect In Bleed Connect state (st_fcs = 19), the coolant heater (HTR303) is enabled to heat the air entering the stack, helping to limit the amount of time spent at OCV (which can lower stack lifetime). The system will then wait for a time of 0.2 seconds before progressing to the next state. Cathode Purge In the Cathode Purge state (st_fcs = 20), the stack bypass valve (FCV205) closes and the air compressor speed is set to achieve a 380SLPM flow rate (4SLPM/cell, 95 cell stack). The following must be confirmed prior to progressing to Run state: a.

The measured RPM feedback signal confirms the compressor is running at >90% of its commanded speed. • If the measured RPM does not reach >90% of its commanded speed within 30 seconds, the system will shut down and log a code for DTC 36.

The minimum cell voltage is >700mV. • If the minimum cell voltage does not reach >700mV within 30 seconds, the system will shut down and log a code for DTC 35.

The ultracapacitor voltage is below the threshold for the truck start without giving a “high voltage” fault code reading (82% for Class I, 92% on Class II). If the voltage is too high, the compressor continues to run at low speed to draw voltage from the ultracapacitors.

Run In Run state (st_fcs = 32), the stack is fully ready to make power. The truck contactor K04 will now close and allow power to the Anderson connector. In Run state, the controls regulate the current requested from the stack to maintain a specific State of Charge (SoC) on the ultracapacitors bank, as well as a consistent charge of 28.8V to the 24V battery system. a.

The nominal desired Run SoC is 76% for Class I systems, and 85% for Class II systems.

The current requested from the stack in turn helps determine the required air flow rate and thereby the speed setpoint for the air compressor.

The heat produced within the stack as it produces current is carried away by our coolant flow, and the temperature of this coolant helps determine the required speed setpoints for our cooling pump (PMP301) and fan (FAN365), and also the required position setpoint of our heat exchanger bypass valve (TCV352).

While in the Run state, the controls are typically able to maintain the nominal Run SoC setpoint, responding to varying truck load demands. But when the load is removed (operator taking a break, etc.), the actual SoC will typically rise above the nominal Run setpoint. Once the SoC reaches a higher threshold (Standby SoC setpoint), a new subset of control logic takes over. • The Standby SoC setpoint is 82% for Class I fuel cell systems, and 90% for Class II fuel cell systems.

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Principles of operation

Standby SoC The Standby SoC threshold is the target for the controls to maintain, and the stack is only operated within a narrower, lower current range (between 2-62.5A). The coolant heater is enabled to be used as a power sink (typically dissipates 8-10A). The system will remain in this mode, maintaining the Standby SoC for 2 minutes, to confirm if the truck load returns. If not, the system will shut off the stack, bleed down its residual voltage, and continue to wait. The fuel cell system remains on, but the stack is offline. During the process of shutting off the stack, the system will progress through the same states as on a normal shutdown initiated by the Stop button, outlined in Stop button, Step a. through Step e. The only difference is that here, Stack Dry Out (st_fcs = 66) only lasts 5 seconds as opposed to the 30 second duration during a full system shutdown. Standby While in Standby with the stack off, the system’s balance of plant components (fans, sensors, etc.) continue to draw power and will gradually decrease the ultracapacitors SoC. Once below a certain Recharge SoC threshold (76% for Class I, 85% for Class II), the stack will power on at low power to recharge the ultracapacitors back to the Standby SoC setpoint. a.

When the stack is powered up, the system will again progress through the states outlined in Anode Start through Cathode Purge before re-entering Run state.

When Standby SoC is reached again, the stack will be shut off.

NOTE: During this time with the stack off, the 24V battery system will continue to charge from the ultracapacitors, instead of the stack. The controls will continue to toggle the stack on and off to maintain ultracapacitors SoC between the Standby SoC and Recharge SoC setpoints until one of the three following outcomes is reached: a.

The system has been in Standby mode for 20 continuous minutes, which initiates a normal shutdown sequence (DTC 102).

The truck load returns, and the ultracapacitors SoC dips below another defined level, the ExitStandby SoC threshold (74% for Class I, 83% for Class II). • The system will return to normal control logic. Any timers and counters related to Standby are reset. The stack is powered back up, and the system will again progress through the states outlined in through before re-entering Run state.

NOTE: if the SoC dips below the ExitStandby SoC threshold before the initial two minute wait period times out, the stack will not ever be shut off despite the system having entered its Standby control mode. c.

The truck load returns at >1kW, and the system returns to normal control logic, as in , but without waiting to drop below the ExitStandby SoC threshold. This will allow the system to respond and get back up to power more quickly.

Once started up and running, the system will remain there unless: • The Stop button is pressed. 152

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Principles of operation

Standby (continued) • A fault occurs. • The 20 minute timeout mentioned in is reached. Start button When the Start button is pressed, the main ventilation fan will begin spinning. Once the airflow is sufficient to satisfy the DPS, relay VENT OK becomes energized. Once VENT OK has been energized for 0.5 seconds (nominal, adjustable), it then allows power to flow to the rest of the system’s nonclassified components including the VSM. Stop button When the Stop button is pressed, the system immediately opens the Truck Load contactor (K04). The stack remains on while the ultracapacitors are charged to a Balancing SoC setpoint (82% for Class I, 92% for Class II). This is referred to as “overcharging”. Overcharging ensures that the system has plenty of voltage for the next start up. Once the Balancing SoC is reached, stack and system shutdown will begin. This includes: a.

Decreasing to a minimum power demand of 2A from the DC/DC converter, and enabling the coolant heater (Min Load state, st_fcs = 64). This state lasts a minimum of 0.2 seconds, up to a maximum of 1 second before progressing to the next state.

Continue flowing hydrogen to the stack with anode purge and drain valves open until the calculated nitrogen concentration is less than 25% (Anode Purge Shutdown state, st_fcs = 65). Minimum time for this state is 1 second. The nitrogen purge will be occur within this time. The maximum amount of time for this state is 30 seconds. The system will then progress to the next state regardless of calculated nitrogen %.

Ramping the compressor to high speed to dry the cell membranes for 30 seconds (Stack Dry Out state, st_fcs = 66). • During this state, hydrogen continues to flow to the stack (supply valves in “pressure control” mode ensuring PT157 is less than 2200mbara), but with the anode purge and drain valves again closed.

Turning off the compressor to eliminate air flow, then bleeding down andy residual voltage on the stack via the coolant heater (Stack Bleed state, st_fcs = 67). The system waits to ensure a min cell voltage less than 50mV and an avg cell voltage less than 100mV before progressing to the next state. • If the minimum cell voltage does not reach ≤ 50mV within 30 seconds, the system will progress to the next state, but log a code for DTC 41. Similarly, if the average cell voltage does not reach ≤ 100mV within 30 seconds, the system will progress to the next state, but log a code for DTC 42. DTCs 41 and 42 typically indicate a problem with either the coolant heater (HTR303) or its drive relay (K02). • During this state, hydrogen continues to flow to the stack (supply valves in “pressure control” mode ensuring PT157 ≤ 2200mbara), but with the anode purge and drain valves again closed.

Waiting for 3 seconds in the Stack Discharged state (st_fcs = 68).

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Principles of operation

Stop button (continued) f. Transitioning back to Off (st_fcs = 8), waiting 3 seconds, and then fully depowering the system via Kswoff. Faults When any fault occurs, the system will first notify the operator via the HMI screen and interrupt the Early Warning System (EWS) signal to the truck indicating that it has experienced an issue. The Truck Load contactor (K04), will remain closed for a full 10 seconds to ensure the truck can safely come to a complete stop. a.

If a minor fault is detected, the system follows a nearly identical path as on a normal shutdown initiated by the Stop button. It immediately disconnects the stack from the DC/DC converter and progresses through the states outlined in 16a-16e to ensure the stack is properly dried and discharged. The only differences are that: • A DTC code is logged to indicate the fault that was experienced. • We transition from the Stack Discharged state (st_fcs = 68) to the Fault state (st_fcs = 2) instead of the Off state prior to depowering via Kswoff.

A major fault is usually indicative of a serious problem with the stack, so we immediately transition to the Fault state (st_fcs = 2), log the DTC code, and depower the system via Kswoff at the end of the EWS period.

If the system ever shuts down without transitioning correctly through the state flow outlined above and without a DTC code, it is reasonable to assume that the reason for the shutdown did not derive from within the control system. The problem could be caused by components in the electromechanical “safety” monitoring circuit, such as the E-Stop, DPS, or WDT.

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Nuvera® Fuel Cell System C95A-33/N95A-21 Diagnostic Troubleshooting Manual

Parts identification and wiring diagrams

Legend

Figure 48. Legend: Parts identification diagram

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Parts identification and wiring diagrams

Parts identification diagram

Figure 49. Parts identification diagram (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R)

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Parts identification and wiring diagrams

Parts identification diagram (continued)

Figure 50. Parts identification diagram (fuel cell systems S/N A2D1S01500R or S/N A2D2S01500R and after)

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Parts identification and wiring diagrams

Wiring diagrams (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R)

Figure 51. Sheet 1 of 9

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Parts identification and wiring diagrams

Wiring diagrams (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) (continued)

Figure 52. Sheet 2 of 9

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Parts identification and wiring diagrams

Wiring diagrams (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) (continued)

Figure 53. Sheet 3 of 9

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Parts identification and wiring diagrams

Wiring diagrams (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) (continued)

Figure 54. Sheet 4 of 9

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Parts identification and wiring diagrams

Wiring diagrams (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) (continued)

Figure 55. Sheet 5 of 9

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Parts identification and wiring diagrams

Wiring diagrams (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) (continued)

Figure 56. Sheet 6 of 9

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Parts identification and wiring diagrams

Wiring diagrams (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) (continued)

Figure 57. Sheet 7 of 9

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Parts identification and wiring diagrams

Wiring diagrams (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) (continued)

Figure 58. Sheet 8 of 9

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Parts identification and wiring diagrams

Wiring diagrams (fuel cell systems up to and including S/N A2D1S01500R or S/N A2D2S01500R) (continued)

Figure 59. Sheet 9 of 9

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Wiring diagrams (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after)

Figure 60. Sheet 1 of 9

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Parts identification and wiring diagrams

Wiring diagrams (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) (continued)

Figure 61. Sheet 2 of 9

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Parts identification and wiring diagrams

Wiring diagrams (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) (continued)

Figure 62. Sheet 3 of 9

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Parts identification and wiring diagrams

Wiring diagrams (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) (continued)

Figure 63. Sheet 4 of 9

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Parts identification and wiring diagrams

Wiring diagrams (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) (continued)

Figure 64. Sheet 5 of 9

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Parts identification and wiring diagrams

Wiring diagrams (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) (continued)

Figure 65. Sheet 6 of 9

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Parts identification and wiring diagrams

Wiring diagrams (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) (continued)

Figure 66. Sheet 7 of 9

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Parts identification and wiring diagrams

Wiring diagrams (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) (continued)

Figure 67. Sheet 8 of 9

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Parts identification and wiring diagrams

Wiring diagrams (fuel cell systems S/N A2D1S01501R or S/N A2D2S01501R and after) (continued)

Figure 68. Sheet 9 of 9

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Notes

| | |

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Nuvera Fuel Cells LLC 129 Concord Road, Bldg. 1 Billerica, MA 01821 USA Tel: (617) 245-7500