HARNESS AS-ENGINE 4947966 - Caterpillar

Table 3
Troubleshooting Test Steps    Values    Results    
1. Inspect the Electrical Connectors and the Wiring
A. Turn the main disconnect switch to the OFF position.
B. Thoroughly inspect connectors (1) through (7) . Inspect all of the connectors that are associated with the circuit. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
C. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connectors that are associated with the circuit.
D. Check the allen head screw for each of the ECM connectors for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
E. Check the harness and wiring for abrasion and for pinch points from the sensors back to the ECM.
   
Connectors    
Results: The harness and connectors appear to be OK.
Proceed to Test Step 2
Results: There is a problem with the connectors and/or wiring.
Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are coupled.
Verify that the repair eliminates the problem.
   
2. Check for Diagnostic Codes that are Active or Logged
A. Connect Cat® Electronic Technician (Cat® ET) to the service tool connector.
B. Restore the electrical power to the ECM.
C. Monitor the active diagnostic code screen on Cat ET. Check and record any diagnostic codes that are active or logged. Look for the following diagnostic codes:
- 1268-5
- 1268-6
- 1269-5
- 1269-6
- 1270-5
- 1270-6
- 1271-5
- 1271-6
- 1272-5
- 1272-6
- 1273-5
- 1273-6
Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
D. Turn the main disconnect switch to the OFF position.
   
Codes    
Results: No diagnostic codes are active or logged.
Repair: There does not appear to be an electrical problem with the ignition system at this time. If the problem is intermittent, refer to Troubleshooting, "Electrical Connectors - Inspect".
Results: A short circuit diagnostic code -5 is active at this time.
Proceed to Test Step 3.
Results: An open circuit diagnostic code -5 is active at this time.
Proceed to Test Step 4.
   
3. Create a Short Circuit at the Harness Connector for the Suspect Transformer
A. Set the engine control to the OFF position. Remove the electrical power from the engine.
B. Short the two terminal connectors together in order to create a test circuit through the ignition harness.
C. Restore the electrical power to the engine. Start the engine.
Note: The engine must be cranking or the engine must be running in order for the diagnostic codes to become active.
D. Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes.
Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
E. Set the engine control to the OFF position. Remove electrical power from the engine.
F. Restore the wiring to the original configuration.    
Short Circuit    
Results: A short circuit diagnostic code -6 is active when the jumper wire is installed. An open circuit diagnostic code -5 is active when the jumper wire is removed.
Repair: The ECM detected the short circuit.