32
UENR4504-03
Symptom Troubleshooting
Table 5
Troubleshooting Test Steps
Values
Results
1. Diagnostic Codes
Engine Derate or Diagnostic Codes
Result: A diagnostic code is present.
Note: Certain diagnostic codes may cause poor performance. A. Use the electronic service tool to check for active or logged diagnostic codes.
2. Parameters in the Electronic Control Module (ECM)
Repair: Troubleshoot the diagnostic code. Refer to Troubleshooting, “Diagnostic Trouble Codes”. Result: A diagnostic code is not present. Proceed to Test Step 2.
Parameters
A. Use the electronic service tool to verify that the correct parameters are being used. Refer to Troubleshooting, “Configuration Parameters” for additional information.
Result: The parameters are not correct. Repair: Input the correct parameters. Refer to Troubleshooting, “Configuration Parameters” for additional information. Result: The parameters are correct. Proceed to Test Step 3.
3. Throttle Position Sensor/Throttle Switches
Electrical connections
Result: The throttle response is not as expected. Repair: If the maximum no-load speed cannot be obtained refer to Troubleshooting, “Switch Circuits - Test (Throttle Switch)” and Troubleshooting, “Mode Selection - Test”.
A. Turn the start switch to the ON position. B. Run the engine until the speed is equal to the maximum noload speed.
If the engine speed is erratic refer to Troubleshooting, “Speed Control - Test”.
C. Use the electronic service tool to make sure that the throttle is set to reach the maximum no-load speed.
Result: All responses are normal. Proceed to Test Step 4.
4. Air Intake and Exhaust System A. Observe the engine warning lamp. Check for an air filter restriction indicator, if equipped. Replace plugged air filters. Refer to the Operation and Maintenance Manual. B. Check the air inlet and exhaust system for restrictions and/or leaks. Refer to Systems Operation/Testing and Adjusting, “Air Inlet and Exhaust System - Inspect”.
Restrictions
Result: There are restrictions in the air inlet or exhaust system. Repair: Make the necessary repairs, Refer to Systems Operation/Testing and Adjusting, “Air Inlet and Exhaust System - Inspect” for additional information. Result: The exhaust system is restricted with white deposits. Repair: Refer to Troubleshooting, “Exhaust System Contains DEF Deposits” Result: There are no restrictions in the air inlet or exhaust system. Proceed to Test Step 5.
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