ENGINE AR-PRIM 4828655 - Caterpillar

Illustration 1 g01409727
Connections of the switch for the continuous work toolThis diagnostic code is associated with the switch for the continuous work tool. The FMI 04 is recorded when the ECM determines that the voltage is below normal for the circuit.The diagnostic code is recorded when both of the inputs are grounded.The possible causes of this diagnostic code are listed below:
The signal circuit (wire M936-BR) is always shorted to ground.
The signal circuit (wire M939-OR) is always shorted to ground.
The switch has failed.
The ECM has failed. This is unlikely.Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all of the connections in the circuit are clean and secure. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.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 2523 FMI 04 is active before performing this procedure.
Table 1
Status of the Switch    
MODE    Switch Position    J2-42
wire M936-BR    J2-43
wire M939-OR    
ON     Up     Open     Closed    
OFF     Down     Closed     Open    Test Step 1. CHECK THE SWITCH
Disconnect the switch from the machine harness.
Check for continuity between contact 5 and contact 4 of the switch.
Press the switch. Release the switch and check for continuity.
Check for continuity between contact 5 and contact 6 of the switch.
Press the switch. Release the switch and check for continuity.Expected Result:The continuity check agrees with Table 1.Results:
OK - The continuity check agrees. Proceed to Test Step 2.
NOT OK - The continuity check does not agree. The switch has failed.Repair: Replace the switch. Verify that the new switch corrects the diagnostic code.STOPTest Step 2. CHECK THE SIGNAL CIRCUITS FOR A SHORT TO GROUND
Reconnect the switch to the machine harness.
Disconnect the J1 and J2 machine harness connectors from the ECM.
At the machine harness connector for the ECM, check for continuity between contact J2-42 (wire M936-BR) and all possible sources of negative battery.
Press the switch. Release the switch and check for continuity.
At the machine harness connector for the ECM, check for continuity between contact J2-43 (wire M939-OR) and all possible sources of negative battery.
Press the switch. Release the switch and check for continuity.Expected Result:The continuity check agrees with Table 1.Results:
OK - The continuity check agrees.Repair: Check the status of the diagnostic code. If the cause of the problem is not found, contact your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM requires replacement, see Troubleshooting, "Electronic Control Module (ECM) - Replace".STOP
NOT OK - The continuity check does not agree.Repair: There is a short in the machine harness to ground. Repair the machine harness or replace the machine harness.STOP