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| Illustration 1 | g00609101 |
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Schematic of the Parking Brake Solenoid | |
This diagnostic code is for the Parking Brake Solenoid.
This diagnostic code is recorded when the voltage of the solenoid circuit is above normal.
System Response:
The brakes will not disengage and the machine will not move.
Note: Ensure that the diagnostic code (CID 0681 FMI 03) is on hold and that the diagnostic code indicator shows "SERV CODE". CID 0681 FMI 03 will only show "SERV CODE" when the parking brake switch is in the OFF position. CID 0681 FMI 03 can be logged if the brake backup pole of the parking brake switch fails to open.
Test Step 1. CHECK THE PARKING BRAKE SWITCH.
- The contacts of the brake backup pole should OPEN with the switch in the OFF position.
- Turn the key start switch to the OFF position.
- Disconnect the machine harness from the connector of the switch.
- With the switch in the OFF position, measure the resistance from contact 8 to contact 9 on the connector for machines that have clutch/brake steering. With the switch in the OFF position, measure the resistance from contact 7 to contact 9 on the connector for machines that have differential steering.
Expected Result:
The resistance should be greater than 5000 ohms .
Results:
- OK - The resistance is greater than 5000 ohms . The switch is correct. Proceed to Test Step 2.
- NOT OK - The resistance is not greater than 5000 ohms .
Repair: The switch has failed. Replace the switch. Before the parking brake switch is replaced, ensure that the measurement for resistance was made with the parking brake switch in the OFF position.
STOP
Test Step 2. CHECK THE SIGNAL CIRCUIT FOR A SHORT TO +BATTERY.
- The machine harness remains disconnected from the switch.
- Turn the key start switch to the OFF position.
- Disconnect the machine harness from the parking brake solenoid.
- Disconnect the machine harness connectors J1 and J2 from the ECM.
- At machine harness connector J2, measure the resistance from contact J2-1 (solenoid signal) to all possible sources of positive voltage. The possible sources of positive voltage are contacts J1-1, J1-4, j1-6, J1-8, J1-10, J1-11, J1-12, J1-17, J1-18, J1-40, J2-2, J2-7, J2-8, J2-13, J2-19, and J2-37.
Expected Result:
Each resistance should be greater than 5000 ohms.
Results:
- OK - Each resistance is greater than 5000 ohms. The machine harness is correct. Proceed to Test Step 3.
- NOT OK - Each resistance is not greater than 5000 ohms.
Repair: There is a short in the machine harness. The short is between J2-1 (G730-PK(Pink)) and the circuit that has a low resistance measurement. Repair the machine harness or replace the machine harness.
STOP
Test Step 3. CHECK IF THE DIAGNOSTIC CODE IS STILL ACTIVE.
- Remove connectors J1 and J2 from the ECM. Inspect the contacts and clean the contacts of the harness connectors.
- Reconnect all harness connectors.
- Turn the key start switch to the ON position.
- Enter service mode of the Caterpillar Monitoring System and clear all inactive diagnostic codes.
- Operate the machine.
- Stop the machine and place the parking brake switch in the OFF position.
- Determine if CID 0681 FMI 03 diagnostic code is present.
Expected Result:
CID 0681 FMI 03 diagnostic code is present. "SERV CODE" is showing.
Results:
- YES - CID 0681 FMI 03 diagnostic code is present. "SERV CODE" is showing.
Repair: The problem has not been corrected. It is unlikely that the ECM has failed. Perform the previous Steps again. If the cause of the diagnostic code is not found, replace the power train ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".
STOP
- NO - CID 0681 FMI 03 diagnostic code is not present. "SERV CODE" is not showing.
Repair: The problem does not exist at this time. Resume normal machine operation.
STOP