CASE AS 8R7926 - Caterpillar

Illustration 1 g02548997
Connections of the Back Up Alarm Relay
This diagnostic code is associated with the Back Up Alarm Relay. The backup alarm relay is controlled by the ECM through an ON/OFF output driver. The FMI 06 means that the ECM has energized the output for the relay and the current for the relay circuit is above normal.The conditions that could cause this diagnostic code to activate are listed:
The relay has failed.
The energize circuit of the relay is shorted to a ground source.
The ECM has failed. The failure of the ECM 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 meet the following requirements: clean, secure, and 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 cause other diagnostic codes to be activated. Ignore these created diagnostic codes and clear the diagnostic codes when the problem has been corrected.Note: Use a calibrated digital multimeter for the measurements in this procedure.System Response:The backup alarm is off.Test Step 1. CHECK THE RELAY
Turn the key start switch and the disconnect switch to the ON position.
While the status of the active CID 0144 FMI 06 diagnostic code is being observed, disconnect the backup alarm relay from the machine harness.Expected Result:When the relay is disconnected from the harness, the CID 0144 FMI 06 diagnostic code is no longer active. A CID 0144 FMI 05 is now active.Results:
OK - When the relay is disconnected from the harness, the CID 0144 FMI 06 diagnostic code is no longer active. A CID 0144 FMI 05 diagnostic code becomes active. The relay is causing the problem.Repair: Verify that the relay has failed by substituting a known good relay that is the same part number for the suspect relay. Replace the suspect relay.STOP
NOT OK - The status of the active CID 0144 FMI 06 diagnostic code did not change when the relay was disconnected from the machine harness. The relay is not causing the problem. Proceed to Test Step 2.Test Step 2. CHECK THE ENERGIZE CIRCUIT OF THE RELAY FOR A SHORTThe relay remains disconnected from the machine harness.
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness connectors J1 and J2 from the ECM for the Transmission.
At the machine harness connector J1 for the ECM, measure the resistance from contact J1-12 (wire 331-OR(Orange)) to frame ground. Measure the resistance from contact J1-12 (wire 331-OR(Orange)) to all other contacts used in the machine harness connectors J1 and J2 for the ECM.Expected Result:Each resistance measurement is greater than 5000 ohms.Results:
OK - Each resistance measurement is greater than 5000 ohms. The energize circuit is not shorted to another circuit in the machine harness. Proceed to Test Step 3.
NOT OK - Each resistance measurement is not greater than