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| Illustration 1 | g01252077 |
Parking brake solenoid | |
This diagnostic code is associated with the parking brake solenoid valve. The FMI 03 means that the ECM has determined that the voltage of the solenoid circuit is above normal.
The possible causes of the diagnostic code are listed:
- The solenoid has failed.
- The energize circuit of the solenoid is shorted to the +battery circuit.
- The ECM has failed.ECM failure 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 0681 FMI 03 is active before performing this procedure.
Note: Use a calibrated 146-4080 Digital Multimeter for the measurements in this procedure.
System Response:
A short to battery will cause the park and secondary brakes not to function properly when there is accumulator pressure or the engine is running. If this condition exists, take care operating the machine. Chock the wheels and use the service brake to stop the vehicle while there is brake system pressure.
Test Step 1. CHECK THE ENERGIZE CIRCUIT OF THE SOLENOID FOR A SHORT TO THE +BATTERY CIRCUIT.
- Turn the keyswitch and the disconnect switch to the OFF position.
- Disconnect the harness connectors from the solenoid and the ECM.
- At the harness connector for the ECM, measure the resistance from contact J1-61 (wire A958-WH) to all contacts that are used in the 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 harness is correct. Proceed to Test Step 3.
- NOT OK - Each resistance measurement is not greater than 5000 ohms. There is a short in the harness. The short is between J1-61 (A958-WH) and the circuit that has a low resistance measurement.
Repair: Repair or replace the harness.
STOP
Test Step 2. CHECK THE SENSOR
- Verify that the keyswitch and the disconnect switch are in the OFF position.
- Disconnect the solenoid with the active diagnostic code from the harness.
- Check the resistance of the solenoid with a calibrated digital multimeter.
Expected Result:
The resistance of the solenoid is more than 100 ohms.
Results:
- YES - The resistance of the solenoid is more than 100 ohms. Proceed to Test Step 3.
- NO - The resistance of the solenoid is less than 100 ohms. The solenoid has failed.
Repair: The solenoid has failed. Replace the solenoid. Verify that the new solenoid corrects the problem.
STOP
Test Step 3. CHECK IF THE DIAGNOSTIC CODE IS STILL ACTIVE.
- Inspect the contacts and clean the contacts of the harness connectors.
- Reconnect all harness connectors.
- Turn the disconnect switch and the keyswitch to the ON position.
- Operate the machine.
- Determine if the CID 0681 FMI 03 is active.
Expected Result:
The CID 0681 FMI 03 is not active.
Results:
- NO - The CID 0681 FMI 03 is active. The problem has not been corrected. The ECM may have failed, however, ECM failure is unlikely.
Repair: Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, contact the technical communicator at your Caterpillar dealer. If the ECM must be replaced, refer to the Testing and Adjusting, "Electronic Control Module (ECM) - Replace" section of this manual.
STOP
- YES - The CID 0681 FMI 03 is not active. The problem does not exist at this time.
Repair: The diagnostic code was probably caused by a poor connection or a short at one of the harness connectors that was disconnected and reconnected. Resume normal machine operation.
STOP