CUTTING EDGE 4T6620 - Caterpillar

Illustration 1 g02373096
Schematic for the parking brake pressure switchThis diagnostic code is associated with the parking brake pressure switch. The switch is connected to two inputs of the ECM. One of the inputs is open and the other input is grounded during proper operation.The FMI 04 means that the ECM has determined that the "Normally Open" and "Normally Closed" circuits are 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 0627 FMI 04 is active before performing this procedure.Test Step 1. CHECK THE HARNESS
Turn the battery disconnect switch and the key start switch to the OFF position.
Disconnect the machine harness from the switch.
Disconnect the machine harness connectors from the ECM.
Measure the resistance between contacts J1-37 (wire D735-PK) and J1-39 (wire D756-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. Proceed to Test Step 2.
NO - One or more of the resistance measurements are less than 5 ohms. The harness has failed. The short is betweenJ1-37 (wire D735-PK) and the circuit with the lowest resistance or the short is between J1-39 (wire D756-YL) and the circuit with the lowest resistance.Repair: Repair the wiring harness or replace the wiring harness.STOPTest Step 2. CHECK IF THE DIAGNOSTIC CODE REMAINS
Inspect the contacts of the harness connectors and clean the connectors.
Reconnect all harness connectors.
Turn the battery disconnect switch and the key start switch to the ON position.
Operate the machine.
Determine if CID 0627 FMI 04 is present.Expected Result:The CID 0627 FMI 04 is active. Results:
YES - The CID 0627 FMI 04 is active. The diagnostic code has not been corrected. The ECM may have failed.Repair: The ECM may have failed, but is unlikely. 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 - The CID 0627 FMI 04 is not active. The diagnostic code does not exist at this time. Repair: The initial diagnostic code was probably caused by a poor electrical connection or a short at one of the harness connectors when disconnected and reconnected. Resume normal machine operation.STOP