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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 Sensor power supply. An FMI 03 code means the Transmission ECM has determined the output voltage level of the power supply is above normal.
Possible causes of this diagnostic code are listed:
- The power supply output circuit is shorted to another voltage source.
- The ECM may have failed, but is unlikely.
Test Step 1. CHECK THE 8 VDC SENSOR POWER SUPPLY VOLTAGE AT THE ECM.
- Turn the disconnect switch and the key start switch to the ON position. Do not start the engine.
- Do not disconnect the machine harness connectors from the Transmission ECM.
- Measure the DC voltage between the ECM J1 harness connector contacts J1-44 (X800-OR) and J1-45 (J764-BR).
Expected Result:
The voltage is 8.0 ± 0.5 VDC.
Results:
- YES - The voltage is 8.0 or ± 0.5 VDC. The sensor power supply voltage is correct.
Repair: Check if the diagnostic code is still active.
If the diagnostic code is still present, go to Test Step 3
- NO - The voltage is greater than 8.0 ± 0.5 VDC. The sensor power supply voltage is NOT correct. Go to Test Step 2.
Test Step 2. CHECK FOR A SHORT CIRCUIT IN THE MACHINE HARNESS.
- Turn the disconnect switch and the key start switch to the OFF position.
- Disconnect the multimeter probes from the ECM harness connector. Disconnect the J1 and J2 harness connectors from the Transmission ECM.
- At the J1 harness connector for the ECM, measure the resistance between contact J1-44 (X800-OR) and all of the other contacts used on both of the Transmission ECM harness connectors.
Expected Result:
Each resistance measures more than 5000 ohms.
Results:
- YES - Each resistance measures more than 5000 ohms. The +8 VDC sensor power supply is not shorted to another circuit in the harness.
Repair: Check again to verify if the diagnostic code is still active.
If the code is still active, go to Test Step 3.
- NO - A resistance measurement is less than 5000 ohms. There is a short circuit between contact J1-44 (wire X800-OR) and the wire with the low resistance measurement.
Repair: Repair, or replace, the harness.
Go to Test Step 3.
Test Step 3. CHECK THE STATUS OF THE DIAGNOSTIC CODE
- Inspect the disconnected harness connectors. Clean the contacts of the harness connectors. Check the wires for damage to the insulation that can be caused by excessive heat or chafing.
Note: Disconnect the J1 and J2 Transmission ECM harness connectors and all of the 8 VDC sensor power supply connectors prior to performing this step.
- Reconnect all harness connectors. Make sure that the connectors are fully seated and that the clips for each connector are fastened. Ensure that the retaining bolts are properly tightened.
- Turn the disconnect switch and the key start switch to the ON position. Do not start the engine.
- Check to see if the CID 0041 FMI 03 diagnostic code is still active.
Expected Result:
The CID 0041 FMI 03 diagnostic code is no longer active.
Results:
- YES - The CID 0041 FMI 03 diagnostic code is no longer active. The problem does not exist at this time.
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 operation.
STOP
- NO - The CID 0041 FMI 03 diagnostic code is still active. The problem has not been corrected.
Repair: If the diagnostic code remains active or if the diagnostic code activates repeatedly and no cause can be found, the ECM could be failing.Verify that all other possible causes of this diagnostic code have been investigated. If the cause of the active diagnostic code is not found, contact your Dealership Technical Communicator for possible consultation with Caterpillar.If the Transmission Electronic Control Module (ECM) must be replaced, refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace".
STOP