Model 4700 Maintenance Manual
Section 6. Messages and Codes Fault Codes
Refer to the “Pinout Matrix” located in Theory of Operation section for all voltage and resistance values and component interconnection. Code
Description
Notes/Corrective Action
68
Code 68: Traction Contactor Open When Commanded Closed Correct voltage is not seen by the TPA at +V when CT3 is commanded closed.
Inspect the contactor for physical binding and welded tips. Check the fuse for the TPA (FT). Measure voltage and resistance across coil. Test cables from battery to TPA for continuity and correct torque. If OK, replace the TPA.
69
Code 69: Slave TPA Internal Fault The TPA has detected an internal fault.
Check cables to the motors and TPA for continuity and correct torque. If OK, replace the TPA.
70
Code 70: Slave TPA Precharge Failure When CT3 is closed, the Slave TPA attempts to charge the internal capacitors. If the capacitors are not charged to B+ in a certain amount of time, this code is displayed.
Check for B– at the TPA power input. Check for B+ from CT3 to the B+ connection on the TPA. If not present, check the fuse for the TPA (FT). Measure voltage and resistance across CT3 coil. If OK, replace the TPA.
71
Code 71: Slave TPA Over Temperature Internal temperature of the Slave TPA is >167°F (75°C). Performance is reduced to 212°F (100°C); travel is shut down above 212°F (100°C).
Check fan for correct operation. Fan should operate within about one minute after turning Key switch ON. If not, troubleshoot fan. Allow TPA time to cool. If code clears, check cables to traction motor and TPA for correct torque and continuity. Check for brake drag. If code does not go away, replace TPA.
72
Code 72: Left Traction Motor Temperature Out-of-Range Left traction motor overtemperature, >266°F (130°C), or temperature switch is bad.
If motor temperature is <266°F (130°C), check wiring to switch from VM. If motor temperature is >266°F (130°C), compare current across the 3 phases for excessive current draw per the Pinout Matrix. Check drive unit for binding. If OK, replace the TPA.
73
Code 73: Left Traction Motor Encoder Error Incorrect or no input seen by the TPA from the Left Traction Motor encoder.
Test the +12V and GND inputs to both encoders and the output from channels A and B to the amp from both encoders. If OK, check for shorts to frame. Check voltage to the TPA. If OK, replace the TPA.
74
Code 74: Slave TPA Temperature Sensor Out-of Range Temperature sensor has exceeded values expected.
Check fan for correct operation. Fan should operate within approx. one minute after turning Key switch ON. If not, troubleshoot fan. If OK, replace the TPA.
Publication 1160093, Issued: 20 May 2013
6-19
