PULLER A. 8B7554 - Caterpillar

Illustration 1 g02746897
Schematic of the Master Fault LampThis diagnostic code is recorded when the ECM reads the voltage of the circuit for the Master Fault Lamp as above normal. The action lamp is ON CONTINUOUSLY as a result of this diagnostic code. The schematic that is shown above represents a typical installation of the component. Verify the connector contact and wire numbers by using the Electrical System Schematic for the machine that is being serviced. Test Step 1. CHECK THE LAMP CIRCUIT.
Turn the disconnect switch and the key start switch to the OFF position.
Disconnect the machine harness from the ECM.
Turn the disconnect switch to the ON position.
Observe the Master Fault Lamp.
Turn the key start switch to the ON position.Expected Result:The action lamp is ON.Results:
OK - The Master Fault Lamp is ON. The harness circuit 411-PK is shorted to the +battery. Repair: Repair the harness or replace the harness.STOP
NOT OK - The Master Fault Lamp is OFF. The module has failed.Repair: An ECM failure is unlikely. Exit this procedure and perform this procedure again. Also, recheck if the diagnostic code indicator is illuminated for this diagnostic code. If the cause of the diagnostic code is not found, replace the ECM. See Troubleshooting, "Main Display Module - Replace".STOP