PIPE 3D7769 - Caterpillar

Illustration 1 g02867776
Schematic of the remote control service brake circuitThis diagnostic code is associated with the remote control service brake relays. The relays are connected to two inputs of the Electronic Control Module (ECM). One input is open and the other input is grounded during proper operation.The FMI 04 means that the ECM has determined that the normally open contact and the normally closed contact are closed.This diagnostic code is active when the remote control switch on the machine is in the ON position.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 1928 FMI 04 is active before performing this procedure.Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.Note: The remote control switch on the machine must be in the ON position while troubleshooting the diagnostic code.System Response:When this diagnostic code is active, the ECM will not disengage the parking brake.Test Step 1. CHECK THE RELAY
Move the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness from the interface control module.
Move the key start switch and the disconnect switch to the ON position. Do not start the engine.Expected Result:CID 1928 FMI 04 has been replaced by CID 1928 FMI 03.Results:
YES - CID 1928 FMI 04 has been replaced by CID 1928 FMI 03. The machine harness and the ECM are correct. Proceed to Test Step 3.
NO - CID 1928 FMI 04 is still active. Proceed to Test Step 2.Test Step 2. CHECK THE HARNESS
Move the disconnect switch and the key start switch to the OFF position.
The machine harness remains disconnected from the interface control module.
Disconnect the machine harness connectors from the ECM.
Measure the resistance between contacts J2-29 (wire EL398-BR) and J2-30 (wire EL300-YL) of the machine harness to all the contacts that are used in machine harness connectors for the ECM.Expected Result:Each resistance measurement is greater than 5 ohms.Results:
YES - Each resistance measurement is greater than 5 ohms. The ECM has failed.Repair: The ECM is unlikely to have failed. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, replace the ECM. Refer to Troubleshooting, Testing, and Adjusting, "Electronic Control Module (ECM) - Replace".STOP
NO - One or more of the resistance measurements are less than 5 ohms. The harness has failed. The short is between J2-29 (wire EL398-BR) or J2-30 (wire EL300-YL) and the circuit with the lowest resistance measurement. Repair: Repair the machine harness or replace the machine harness.STOPTest Step 3. CHECK THE RELAY CIRCUIT FOR A SHORT TO GROUND
The disconnect switch and the key start switch remain in the OFF position.
The machine harness remains disconnected from the ECM.
Connect the machine harness to the interface control module.
Remove relays "4" and "5".
Measure the resistance between contact J2-29 (wire EL398-BR) and contact J2-30 (wire EL300-YL). Note