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| Illustration 1 | g02143403 |
Schematic for the 8 VDC sensor power supply circuits | |
This diagnostic code is associated with the 8 VDC power supply for the sensors. The FMI 04 means that the Transmission ECM has determined that the voltage of the 8 VDC sensor power supply is below normal.
The possible causes of the diagnostic code are:
- A sensor has failed.
- The 8 VDC sensor power supply is shorted to ground.
- The Transmission ECM might have failed but that is unlikely.
Test Step 1. CHECK ALL OF THE 8 VOLT SENSORS
- Turn the disconnect switch and the key start switch to the ON position.
- Ensure that the CID 0041 FMI 04 diagnostic code is active.
- One at a time, disconnect each sensor on the machine that is connected to the 8 VDC power supply contact J1-44 (wire X800-OR). Observe the status of the diagnostic code each time you disconnect a sensor.
If the results are OK, fully reconnect one sensor before proceeding to disconnect the next.
Expected Result:
The CID 0041 FMI 04 diagnostic code remains active.
Results:
- OK - The CID 0041 FMI 04 diagnostic code remains active. The sensor is correct. Continue testing the sensors and proceed to Test Step 2 only after all of the required sensors have been tested, and all have proven correct.
- NOT OK - The diagnostic code is no longer active. The sensor has failed.
Repair: Replace the failed sensor.
STOP
Test Step 2. CHECK THE WIRING HARNESS FOR A SHORT TO GROUND.
- Turn the key start switch and the disconnect switch to the OFF position.
- Disconnect the J1 and J2 machine harness connectors from the Transmission ECM.
- Disconnect all of the 8 VDC sensors connected to contact J1-44 (wire X800-OR) from the machine harness.
- At the J1harness connector for the Transmission ECM, measure the resistance from contact J1-44 (wire X800-OR) to all possible sources of ground. Measure also the resistance from contact J1-44 (wire X800-OR) to all of the other contacts on both the J1 and J2 connectors for the ECM.
Expected Result:
Each resistance measurement is greater than 5000 ohms.
Results:
- OK - Each resistance measurement is greater than 5000 ohms. The machine harness is correct. Proceed to Test Step 3.
- NOT OK - One or more resistance measurements are not correct. There is a short in the machine harness.
Repair: The short is between signal contact J1-44 (wire X800-OR) and the circuit with the low resistance measurement. Repair, or replace, the machine harness.
STOP
Test Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS.
- Inspect the contacts of the harness connectors. Clean all of the contacts of the harness connector.
- Reconnect all harness connectors.
- Turn the disconnect switch and the key start switch to the ON position.
- Operate the machine.
- Check the status of the CID 0041 FMI 04 diagnostic code.
Expected Result:
The CID 0041 FMI 04 diagnostic code is no longer active.
Results:
- YES - The CID 0041 FMI 04 diagnostic code is no longer active. The diagnostic code has been corrected.
Repair: The diagnostic code was probably caused by a poor electrical connection that was resolved when a harness connector was disconnected and reconnected. Resume normal machine operations.
STOP
- NO - The CID 0041 FMI 04 diagnostic code is still active. The diagnostic code has not been corrected.
Repair: Is unlikely that the Transmission ECM has failed. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, contact your Dealership Technical Communicator for possible consultation with Caterpillar. If the Transmission ECM needs to be replaced, consult Troubleshooting, "Electronic Control Module (ECM) - Replace".
STOP