LATCH A 9H1749 - Caterpillar

Illustration 1 g02358996
Connections of the backup alarm
This diagnostic code is associated with the backup alarm. The FMI 05 means that the ECM has determined that the current of the alarm circuit is below normal. The possible causes of this diagnostic code are listed below:
The energize circuit of the alarm is open.
The return circuit of the alarm is open.
The alarm has failed.
The ECM has failed. The ECM failing 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.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the problem has been corrected. Verify that the CID 0637 FMI 05 is active before performing this procedure.Use a digital multimeter for the measurements in this procedure.Test Step 1. CHECK THE ALARM.
Turn the disconnect switch and the key start switch to the ON position. Do not start the engine.
Disconnect the alarm with the active diagnostic code from the machine harness.
At the machine harness connector for the alarm, place a jumper wire from contact 1 (wire 321-BR(Brown)) to contact 2 (wire J815-BK(Black)).
Observe the status of the diagnostic code. Expected Result:The diagnostic code remains active. The FMI 05 is still active.Results:
YES - The diagnostic code remains active. The jumper wire does not affect the diagnostic code. Proceed to Test Step 2.
NO - The diagnostic is no longer active. The alarm has failed.Repair: The alarm has failed. Repeat this Test Step "CHECK THE ALARM"