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| Illustration 1 | g02719178 |
Schematic of the secondary steering relay | |
This diagnostic code is associated with the secondary steering relay. The FMI 03 diagnostic code means that the ECM has determined that the voltage of the relay circuit is above normal.
The possible causes of this diagnostic code are listed below:
- The relay has failed.
- The relay circuit is shorted to the +battery circuit.
- The Chassis ECM has failed. A failure of the ECM is unlikely.
Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear these diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 0420 FMI 03 is active before performing this procedure.
Note: Use the digital multimeter for the measurements in this procedure.
System Response:
The system for the secondary steering is energized at all times.
Test Step 1. CHECK THE RELAY CIRCUIT FOR A SHORT TO THE +BATTERY CIRCUIT
- Turn the key start switch and the disconnect switch to the OFF position.
- Disconnect the machine harness connectors from the relay and the ECM.
- At the machine harness connector for the ECM, measure the resistance from contact J2-2 (wire 727-GN) to all contacts that are used in the machine harness 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 2.
- NOT OK - Each resistance measurement is not greater than 5000 ohms. There is a short in the machine harness. The short is between J2-2 (727-GN) and the circuit that has a low resistance measurement.
Repair: Repair the machine harness or replace the machine harness.
STOP
Test Step 2. CHECK IF THE DIAGNOSTIC CODE IS STILL ACTIVE
- Inspect the harness connectors. Clean the contacts of the harness connectors. Check the wires for damage to the insulation that is caused by excessive heat, battery acid, or chafing.
- Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit.
- Reconnect all harness connectors. Make sure that the connectors are fully seated. Observe that the clips for each connector are fastened securely.
- Turn the disconnect switch and the key start switch to the ON position.
- Operate the machine.
- Determine if the CID 0420 FMI 03 diagnostic code is active.
Expected Result:
The CID 0420 FMI 03 diagnostic code is active.
Results:
- YES - The CID 0420 FMI 03 diagnostic code is active. The problem has not been corrected. The ECM may have failed.
Repair: Check the circuit again. If the Cat Electronic Technician (ET) is available, use the service tool to perform a "Wiggle Test". The "Wiggle Test" can detect intermittent short circuits and momentary open circuits in the wiring harness of the machine. A failure of the Chassis ECM is unlikely. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, replace the ECM. Prior to replacing an ECM, always contact your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".
STOP
- NO - The CID 0420 FMI 03 diagnostic code is not active. The problem does not exist at this time. The initial diagnostic code was probably caused by a poor electrical connection or a short at one of the harness connectors. Resume normal machine operation.STOP