BOOM GP-MATERIAL HANDLING 1284370 - Caterpillar

Illustration 1 g02710604
Connections of the 8 Volt DC SupplyThe diagnostic code is recorded when the ECM indicates that the voltage of the sensor supply circuit is too low. Possible causes of this diagnostic code are listed:
The sensor supply output circuit is shorted to a ground source.
A sensor has failed.
The ECM has failed. This situation 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 are clean and secure. Verify that all connections in the circuit are 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. After making any possible fix to the circuit, cycle the Key Switch in order to determine if the Diagnostic Code still exists. Some Diagnostic Codes may not display until the engine is running. Verify that the CID 0041 FMI 04 is active before performing this procedure.Use a digital multimeter for the measurements in this procedure.System Response:
A Level 3 warning is generated.
All of the sensors that receive power from the 8 volt supply are disabled.Test Step 1. CHECK THE POWER SUPPLY AT THE ECM
Turn the disconnect switch and the key start switch to the OFF position.
At ECM connector C1 use a 151-6320 Wire Removal Tool or a similar tool to remove the supply wire and socket at contact C1-8 (wire J852-OR) and the return wire and socket at contact C1-9 (wire J853-BK) from the connector. The machine harness connector C1 remains connected to the ECM.
Turn the disconnect switch and the key start switch to the ON position.
Use the multimeter probes in order to make contact on the ECM connector pins. Measure the voltage at the ECM between the power supply contact C1-8 and the return contact C1-9.Expected Result:The voltage measurement is 8.0 1.0 VDC and the diagnostic should not be active.Results:
OK - The voltage measurement is 8.0 1.0 VDC and the diagnostic is no longer active. Turn the key start switch and the disconnect switch to the OFF position. Install the wires and sockets that were removed from the C1 connector back into the original locations. Proceed to Test Step 2.
NOT OK - The voltage measurement is not 8.0 1.0 VDC and the diagnostic code is still active. The ECM power supply is not correct.Repair: Prior to replacing an ECM, contact the Technical Communicator for your dealer for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM requires replacement, refer to Troubleshooting, "Electronic Control Module (ECM) - Replace".STOPTest Step 2. CHECK THE COMPONENTS
Turn the key start switch and the disconnect switch to the ON position.
While observing the status of the diagnostic code, one at a time, disconnect each of the components that are supplied power by ECM 8 VDC power suppy.Expected Result:The CID 0041 FMI 04 diagnostic code is no longer active when