950M and 962M Wheel Loaders Caterpillar

Alarm - Test

Usage:

962M EJB

Implement ECM

The following is a list of Diagnostic Trouble Codes (DTCs) that are associated with the alarm circuits of the machine.

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Table 1
Implement ECM (MID 82)
DTC	Code Description	System Response
637-3	Backup Alarm: Voltage Above Normal	Backup Alarm will be non-functional.
637-6	Backup Alarm: Current Above Normal	Backup Alarm will be non-functional.
2914-3	Machine Feature Audible Indicator: Voltage Above Normal	Machine Feature Alarm will be non-functional.
2914-5	Machine Feature Audible Indicator: Current Below Normal	Machine Feature Alarm will be non-functional.
2914-6	Machine Feature Audible Indicator: Current Above Normal	Machine Feature Alarm will be non-functional.

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 ECM 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 ECM has failed. A failure of the ECM 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.

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Illustration 1	g03592339
Schematic of the Alarm circuits

Note: The diagram above is a simplified schematic of the connections for the alarm circuits. The schematic is electrically correct. However, not all of the possible harness connectors are shown. Refer to the latest revision of the Electrical Schematic, UENR3117 for the complete schematic.

Diagnostic Trouble Code Procedure

Note: Prior to beginning this procedure, inspect the harness connectors that are involved in this 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 a troubleshooting procedure. For sensors powered via the fuse panel, check the condition of the appropriate fuse before beginning the troubleshooting procedure.

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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 3. FMI 6 diagnostic code, proceed to Test Step 8.
Begin Process For FMI 3 Troubleshooting HERE
2. Check The Energize Circuit Of The Alarm For A Short To The +Battery Circuit. A. Turn the key start switch and the disconnect switch to the OFF position. B. Disconnect the alarm with the active diagnostic code from the machine harness. Disconnect the harness from the ECM. C. At the machine harness connector for the ECM, measure the resistance from the signal harness contact for the alarm to all contacts used in the machine harness connectors for the ECM.	Each resistance measurement is greater than 5K ohms.	OK - Each resistance measurement is greater than 5K ohms. The machine harness is correct. Proceed to Test Step 9. NOT OK - Each resistance measurement is not greater than 5K ohms. There is a short in the machine harness. The short is between the signal wire for the alarm and the wire that measured low resistance. Repair: Repair the machine harness or replace the machine harness. Proceed to Test Step 9.
Begin Process For FMI 5 Troubleshooting HERE
3. Check The Alarm A. Turn key start switch and disconnect switch ON. B. Ensure that the diagnostic code is active. C. Disconnect the alarm with the active diagnostic code from the machine harness. D. At the machine harness connector for the alarm, place a jumper wire from contact 1 to contact 2. E. Observe the status of the diagnostic code.	The diagnostic code remains active. The FMI 05 code is still active.	OK - The diagnostic code remains active. The jumper wire does not affect the diagnostic code. Proceed to Test Step 4. NOT OK - The diagnostic is no longer active. The alarm has failed. Repair: The alarm has failed. Repeat this Test Step "CHECK THE ALARM" in order to verify the failure of the alarm. Replace the alarm. Verify that the new alarm corrects the problem. Proceed to Test Step 9.
4. Check Wiring Harness For An Open A. Turn the key start switch and disconnect switch to the OFF position. B. The harness connector remains disconnected from the alarm. C. Disconnect the J1 and J2 connectors from the ECM. D. At the harness connector for the alarm, install a jumper wire. E. At the harness connector for the ECM measure the resistance at the contacts for the alarm.	The resistance reading is less than 5 ohms.	OK - The resistance is less than 5 ohms. Proceed to Test Step 9. NOT OK - The resistance is greater than 5K ohms. There is an open circuit in the machine harness. Repair: Either the signal or the return circuit wire is open. Inspect all harness connection points for secure wire connections or corrosion. Repair or replace the harness, if necessary. Note: A resistance greater than 5 ohms but less than 5K ohms indicates a loose connection or a corroded connection in the circuit. A resistance measurement greater than 5K ohms would indicate an open in the circuit. Proceed to Test Step 9.
Begin Process For FMI 6 Troubleshooting HERE
7. Check The Alarm A. Turn the disconnect switch and the key start switch to the ON position. Do not start the engine. B. Observe the status of the diagnostic code. C. Disconnect the alarm with the active diagnostic code from the machine harness.	The FMI 6 diagnostic code changes to an FMI 5.	OK - The FMI 6 diagnostic code changes to an FMI 5 when the alarm is disconnected. The circuit is correct. The alarm has failed. Repeat this test "CHECK THE ALARM" to verify the failure of the alarm. Replace the alarm. Repair: Replace the alarm. NOT OK - The FMI 6 code remains active. Proceed to Test Step 8.
8. Check The Energize Circuit Of The Alarm For A Short To Ground A. The machine harness remains disconnected from the alarm. B. Turn the key start switch and the disconnect switch OFF. C. Disconnect the harness connectors from the ECM. D. At the harness connector for the ECM, measure the resistance between the alarm signal contact and all used in the machine harness connectors for the ECM.	Each resistance measurement is greater than 5K ohms.	OK - Each resistance measurement is greater than 5K ohms. The machine harness is correct. Proceed to Test Step 9. NOT OK - One or more of the resistance measurements are less than 5 ohms. A short circuit exists in the machine harness. Repair: A short circuit exists between the wire for the signal wire of the alarm and the circuit with the low resistance. Repair or replace the machine harness. Note: A resistance that is greater than 5 ohms but less than 5K ohms would indicate a loose connection or a corroded connection in the circuit. Inspect all harness connections for loose wiring or signs of corrosion. Proceed to Test Step 9.
9. Check If The Diagnostic Code Remains A. Turn the key start switch and the disconnect switch ON. B. Clear all diagnostic codes. C. Operate the machine. D. Stop the machine and engage safety lock lever. E. Check if diagnostic code for the alarm is active.	DTC Code is no longer active.	OK - Diagnostic code does not exist at this time. Initial diagnostic code may have been caused by poor electrical connection or short at one of the harness connections. Repair: Resume normal machine operation. STOP NOT OK - Diagnostic trouble code has not been corrected. Repair: If the diagnostic code has not been corrected , the ECM may have failed. Prior to replacing the ECM, contact the Technical Communicator at your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM requires replacement, refer to Troubleshooting, "ECM - Replace". STOP