HOUSING AS-SWING 1550864 - Caterpillar

Illustration 1 g02594937
Connections of the Machine Power Distribution RelayThis diagnostic code is associated with the Machine Power Distribution Relay. This relay is powered by an "ON/OFF" driver circuit. The FMI 03 diagnostic code is activated when the ECM detects an above normal voltage of the relay circuit. This diagnostic code is activated on the ECM via CAN Data Link.The following conditions could cause this diagnostic code to be activated:
The relay has failed.
The relay circuit is shorted to a power source.
The ECM has failed. This condition is unlikely.Note: 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 connections in the circuit are clean, that all connections are secure and that all connections are in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.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.Test Step 1. CHECK THE ENERGIZE CIRCUIT OF THE RELAY FOR A SHORT
Turn the disconnect switch and the key start switch to the OFF position.
Disconnect the machine harness connector from the relay. Disconnect the machine harness connector J2 from the ECM.
At the machine harness connectors for the ECM, measure the resistance between contact J2-6 (wire X721-BR) and each of the other circuits that are used in the J2 connector for the ECM.Expected Result:Each resistance measurement is greater than 5000 ohms.Results:
OK - Each resistance measurement is greater than 5000 ohms. The resistance measurements do not indicate a short to another circuit in the machine harness. Proceed to Test Step 2.
NOT OK - Each resistance measurement is not greater than 5000 ohms. There is a short in the machine harness.Repair: The short is between wire X721-BR and the circuit that measured a low resistance measurement.For information on testing for short circuits and finding short circuits, refer to Testing and Adjusting, "Wiring Harness (Short Circuit) - Test". Repair the machine harness or replace the machine harness.STOPTest Step 2. CHECK THE OPERATION OF THE ECMThe disconnect switch and the key start switch remain in the OFF position. The machine harness connectors for the relay and the ECM remain disconnected.
At the machine harness connector J2 for the ECM, use a 151-6320 Removal Tool to remove the relay wire X721-BR and the socket at contact J2-6 from the harness connector.
Reconnect the machine harness J2 connector to the ECM.
Turn the disconnect switch and the key start switch to the ON position.
Observe the status of the active CID 3470 FMI 03 diagnostic code.Expected Result:The CID 3470 FMI 03 diagnostic code is no longer active. A CID 3470 FMI 05 diagnostic code is now active.Results:
OK - The CID 3470 FMI 03 diagnostic code is no longer active. A CID 3470 FMI 05 diagnostic code has become active after the relay circuit is