SPRING 1659363 - Caterpillar

Table 1
Display Module
DTC Code Description System Response
271-05 Action Alarm: Current Below Normal Alarm will not sound.
271-06 Action Alarm: Current Above Normal Alarm will sound continuously. 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 the diagnostic code is active before performing this procedure.Possible Causes for an FMI 05 Diagnostic code are:
The alarm has failed.
The signal circuit for the alarm is open. Low current would be caused by an open circuit.
The monitor has failed. A failure of the monitor is unlikely.Possible Causes for an FMI 06 Diagnostic code are:
The energize circuit of the Action Alarm is shorted to ground.
The Action Alarm has failed.
The Message display has failed. This condition is unlikely.
Illustration 1 g03578065
Schematic of Action Alarm
Note: The diagram above is a simplified schematic of the connections for the Action Alarm . The schematic is electrically correct. However, not all the possible harness connectors are shown. Refer to the latest revision of Electrical Schematic, KENR9577 for the complete schematic.
Table 2
Troubleshooting Test Steps Values Results
1. Identify The Active Diagnostic Code Associated With The Suspect Circuit
A code is present.
An FMI 05 diagnostic code is present: proceed to Test Step 2.
An FMI 06 diagnostic code is present: proceed to Test Step 5.
Begin Process For DTC-05 Troubleshooting HERE
2. Check The Alarm
A. Turn key start switch and disconnect switch ON.
B. Ensure that the diagnostic code is active.
C. Disconnect alarm from machine harness.
D. At the machine harness connector for the alarm, place a jumper wire from the positive contact to the negative contact.
Observe the status of the DTC- 05.
The DTC-05 remains active.
OK - The diagnostic code has changed to 271-06.
If you replace the alarm with a jumper, the expected result would be that the DTC would change to a DTC-06 code because you have shorted the circuit to ground.
Repair: Replace the alarm. After alarm replacement, confirm that the code is not active.
STOP.
NOT OK - The DTC-05 remains active.
Proceed to Test Step 3.
3. Check The Wiring Harness Of The Alarm For An Open
A. Turn the key start switch and the disconnect switch OFF.
B. Disconnect machine harness connection at the display module.
C. The jumper wire that was installed in the previous test remains in place.
D. At the machine harness connector for the message display, measure resistance from the signal contact of machine harness to all possible sources of ground. Measure the resistance to all the machine harness connector contacts for the monitor.
Each resistance measurement is less than 5 ohms.
OK - Each resistance measurement is less than 5 ohms. The machine harness for the display module is correct.
Proceed to Test Step 4.
NOT OK -The resistance is greater than 5K ohms. The resistance measurement is not correct. There is an open circuit in the machine harness for the display module. The open is in