TRACK GP 3951048 - Caterpillar

Illustration 1 g03643292
Left brake solenoid connectionsThis diagnostic code is recorded when the ECM reads the voltage of the left brake solenoid circuit as above normal. The possible causes of this diagnostic code are listed:
The energize circuit of the solenoid is shorted to a voltage source.
The ECM has failed. This is unlikely.Note: Ensure that the diagnostic code for the solenoid is on hold and that the diagnostic code indicator shows "SERV CODE". Test Step 1. CHECK THE SIGNAL CIRCUIT FOR A SHORT
Turn the key start switch to the OFF position.
Disconnect the machine harness from the solenoid.
Disconnect the machine harness connectors J1 and J2 from the ECM.
At machine harness connector J1, measure the resistance from solenoid signal contact J1-58 (wire F792-WH) to all of the other J1 and J2 contacts.Expected Result:Each resistance measurement should be greater than 5000 ohms. Results:
OK - Each resistance measurement is greater than 5000 ohms. Proceed to Test Step 2.
NOT OK - Each resistance is not greater than 5000 ohms. Repair: There is a short in the machine harness. The short is between the energize wire F792-WH for the solenoid and the circuit with a low resistance measurement.Refer to the complete machine Electrical System Schematic. Examine all of the connectors in the circuits for points in the machine harness where the circuits could be shorted. For information on testing for short circuits and finding short circuits, refer to Testing and Adjusting, "Wiring Harness (Short Circuit) - Test". Repair the machine harness or replace the machine harness.STOPTest Step 2. CHECK THE OPERATION OF THE ECMThe disconnect switch and the key start switch remain in the OFF position. The machine harness connectors for the solenoid and the ECM remain disconnected.
At the machine harness connector J1 for the ECM, use a 151-6320 Removal Tool to remove the solenoid energize wire F792-WH and socket at contact J1-58 from the harness connector.
Reconnect the machine harness J1 and J2 connectors to the ECM.
Turn the disconnect switch and the key start switch to the ON position.
Observe the status of the active CID 0689 FMI 03 diagnostic code.Expected Result:The CID 0689 FMI 03 diagnostic code is no longer active. A CID 0689 FMI 05 diagnostic code is now active.Results:
YES - The CID 0689 FMI 03 diagnostic code is no longer active. A CID 0689 FMI 05 diagnostic code has been activated after the solenoid energize circuit was disconnected. The ECM has responded correctly to the open circuit condition in the solenoid circuit.
Reinstall the disconnected solenoid energize wire back into the correct space in the ECM connector before proceeding to the next test step.
Proceed to Test Step 3.
NO - The CID 0689 FMI 03 diagnostic code remains active. The status of the active diagnostic code did not change when the solenoid energize wire was disconnected from the ECM. Repair: The ECM has not responded correctly to the open condition in the solenoid circuit. The operation of the ECM is not correct.Prior to replacing an ECM, always contact your dealership's Technical Communicator for possible consultation with Caterpillar.