BASE 2Y4569 - Caterpillar

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, secure and 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.Possible Causes for an FMI 3 Diagnostic code are:
The return circuit is open.
The signal circuit is open or the alarm is disconnected.
The signal circuit is shorted to the +battery.
The alarm has failed.
The monitor has failed. This condition is unlikely.Possible Causes for an FMI 5 Diagnostic code are:
The alarm has failed
The signal circuit for the alarm is shorted to ground
The monitor has failed. A failure of the monitor is unlikely.Possible Causes for an FMI 6 Diagnostic code are:
The energize circuit of the backup alarm is shorted to ground.
The backup alarm has failed.
The ECM has failed. This condition is unlikely.
Illustration 1 g02944937
Schematic of Action Alarm
Note: The diagram above is a simplified schematics of the connections for the backup alarm. The schematic is electrically correct. However, not all of the possible harness connectors are shown. Refer to the latest revision of Electrical Schematic, UENR2503 for the complete schematic.
Table 2
Troubleshooting Test Steps Values Results
1. Identify The Active DTC Code Associated With The Suspect Circuit
Code present.
FMI 3 diagnostic code: proceed to Test Step 2.
FMI 5 diagnostic code: proceed to Test Step 5.
FMI 6 diagnostic code: proceed to Test Step 8.
Begin Process For DTC- 3 Troubleshooting HERE
2. Check The Alarm
A. Turn the key start switch and the disconnect switch to the OFF position.
B. Disconnect the alarm from the harness.
C. Use jumpers to connect the respective terminals of the alarm to +battery and ground.
D. Turn the key start switch and the disconnect switch to the ON position.
The alarm sounds
OK - The alarm sounds.
Proceed to Test Step 3.
NOT OK - The alarm does not sound.
Repair: Replace the alarm.
STOP
3. Check For An Open In The Alarm Circuit
A. The key start switch and disconnect switch remain in the OFF position.
B. The harness connector remains disconnected from the alarm.
C. Disconnect the J1 and J2 connectors from the monitor.
D. At the harness connector for the alarm, install a jumper wire.
E. At the harness connector for the monitor measure the resistance at the contacts for the alarm.
The resistance reading is less than 5 Ω.
OK - The resistance is less than 5 Ω.
Proceed to Test Step 4.
NOT OK - The resistance is greater than 5K Ω.
Repair: Either the signal or the return circuit wire is open. Repair or replace the harness.
STOP
4. Check The Signal Circuit For A Short.
A. The disconnect switch and the key start switch remain in the OFF position.
B. The harness connectors J1 and J2 remain disconnected from the monitor.
C. Remove the jumper wire that was installed during the previous Test Step..
D. At the monitor harness connectors measure the resistance between the positive connector and all J1 and J2 contacts.
Each resistance measurement is greater than 5K Ω.
OK