CYLINDER GP-LIFT 2623668 - Caterpillar

Illustration 1 g01004853
Schematic for the brake accumulator oil pressure switch for brake applicationThis diagnostic code is associated with the brake accumulator oil pressure switch for brake application. The switch is connected to one input of the ECM. The contact is open during proper operation.The FMI 04 means that the ECM has determined that the "Normally Open"circuit is grounded.Note: The following test procedure may create other diagnostic codes. Ignore these diagnostic codes and clear these diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 1612 FMI 04 is active before performing this procedure.Test Step 1. CHECK THE SWITCH
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness from the switch.
Turn the key start switch and the disconnect switch to the ON position.Expected Result:The CID 1612 FMI 04 has been replaced by CID 1612 FMI 03.Results:
OK - The CID 1612 FMI 04 has been replaced by CID 1612 FMI 03. The machine harness and the ECM are correct. Proceed to Test Step 3.
NOT OK - The CID 1612 FMI 04 is still active. Proceed to Test Step 2.Test Step 2. CHECK THE HARNESS
Turn the disconnect switch and the key start switch to the OFF position.
The machine harness remains disconnected from the switch.
Disconnect the machine harness connector(s) from the ECM.
Measure the resistance between contacts J2-6 (wire X779-GY) 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: It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, replace the ECM. Refer to Systems Operation, Troubleshooting, Testing and Adjusting, "Electronic Control Module (Power Train) - Replace" for the machine that is being serviced. Stop.
NO - One or more of the resistance measurements are less than 5 ohms. The harness has failed. The short is between J2-6 (wire X779-GY) and the circuit with the lowest resistance.Repair: Repair the wiring harness or replace the wiring harness. Stop.Test Step 3. CHECK THE OPERATION OF THE SWITCH
The machine harness remains disconnected from the switch.
Connect one lead from a multimeter to contact A of the harness connector on the switch.
Connect the other lead from a multimeter to contact B of the harness connector on the switch.
Measure the resistance between contact A and contact B. Note the resistance.
Disconnect the lead from contact B and connect the lead to contact C.
Measure the resistance between contact A and contact C.Expected Result:The resistance from contact A to contact C is less than 5 ohms, and the resistance from contact A to contact B is greater than 5 ohms.Results:
YES - The resistance from contact A to contact C is less than 5 ohms, and the resistance from contact A to contact B is greater than 5 ohms. Proceed to Test Step 4.
NO -