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| Illustration 1 | g03227697 |
Connections of the demand fan solenoid | |
This diagnostic code is associated with the demand fan solenoid. The FMI 03 means that the Transmission ECM has determined that the voltage of the relay circuit is above normal.
The possible causes of the diagnostic code are listed:
- The energize circuit of the relay is shorted to the +battery circuit.
- The Transmission ECM has failed. This is unlikely.
Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all of the connections in the circuit are clean and secure. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.
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 CID 0291 FMI 03 is active before performing this procedure.
Note: Use a digital multimeter for the measurements in this procedure.
Test Step 1. CHECK THE ENERGIZE CIRCUIT OF THE SOLENOID FOR A SHORT TO THE +BATTERY CIRCUIT.
- Turn the key start switch and the disconnect switch to the ON position.
- Disconnect the wires from the back of the connector at the Transmission ECM.
- At the machine harness connector for the solenoid, measure the voltage from contact 2 (wire H746-YL) to frame ground. At the machine harness connector for the solenoid, measure the voltage from contact 1 (wire J808-BK) to frame ground.
Expected Result:
The voltage is 0 VDC.
Results:
- OK - There are no shorts in the wires. Proceed to Test Step 2.
- NOT OK - A voltage is present in the wires. There is a short in the machine harness or in the wires. The short is to a separate voltage source.
Repair: Repair the machine harness or replace the machine harness. Ensure that the fix has corrected the problem.
STOP
Test Step 2. CHECK THE OPERATION OF THE Transmission ECM.
The disconnect switch and the key start switch remain in the OFF position. The machine harness connectors for the solenoid and the Transmission ECM remain disconnected.
- Use a removal tool in order to remove the wire that energizes the solenoid from the harness. Remove wire (H746-YL) from contact J1-68 of the Transmission ECM.
- Reconnect the machine harness connectors to the Transmission ECM.
- Turn the disconnect switch and the key start switch to the ON position.
- Observe the status of the active diagnostic code.
Expected Result:
The diagnostic code of FMI 03 changes to FMI 05.
Results:
- OK - The FMI 03 changes to an FMI 05. The FMI 05 was activated after the energize circuit for the solenoid was disconnected. The Transmission ECM has responded correctly to the condition of an open circuit in the solenoid circuit. Reconnect the disconnected wire. Wire (H746-YL) connects to the Transmission ECM at connector contact J1-68. Proceed to Test Step 3.
- NOT OK - The FMI 03 does not change to an FMI 05. The diagnostic code did not change after the wire for the solenoid was disconnected.
Repair: The Transmission ECM has not responded correctly to the condition of an open circuit in the solenoid circuit. The operation of the Transmission ECM is not correct. Replace the Transmission ECM. Prior to replacing a Transmission ECM, always contact your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. See Troubleshooting, "Electronic Control Module (ECM) - Replace".
STOP
Test Step 3. CHECK IF THE DIAGNOSTIC CODE IS STILL ACTIVE.
- Inspect the harness connectors. Clean the contacts of the harness connectors and check the wires for damage to the insulation that is caused by excessive heat, corrosion, 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 in order to make sure that the connectors are fully seated. Also, make sure that the clips for each connector are completely fastened.
- Turn the disconnect switch and the key start switch to the ON position.
- Operate the machine.
- Determine if the diagnostic code is active.
Expected Result:
The diagnostic code is active.
Results:
- YES - The diagnostic code is active. The problem has not been corrected.
Repair: Check the circuit again. It is unlikely that the Transmission ECM has failed. Exit this procedure and perform this procedure again. Prior to replacing a Transmission ECM, always contact your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the Transmission ECM requires replacement, refer to Troubleshooting, "Electronic Control Module (ECM) - Replace".
STOP
- NO - The diagnostic code is not active. The initial diagnostic code was probably caused by a poor electrical connection or a short at one of the harness connectors that was disconnected and reconnected. The problem does not exist at this time. Resume normal machine operation.STOP