MOTOR & MTG GP-HYDROSTATIC 3561938 - Caterpillar

Illustration 1 g01376780
Connections of the 8 volt supplyThis diagnostic code is associated with the 8 volt supply.This diagnostic code is recorded when the ECM detects the voltage of the 8 volt supply lower than normal.The following conditions could cause this diagnostic code:
A sensor has failed.
The power supply circuit is shorted to a ground source.
The ECM has failed. This 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. Clear the diagnostic codes when the problem has been corrected. Verify that the CID 0041 FMI 04 is active before performing this procedure.System Response:All of the sensors that receive power from the 8 volt supply will be 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 J1, use a wire removal tool to remove the supply wire and the socket. Remove the wires at contact J1-44 (wire 497-BU) and contact J1-45 (wire J766-PU) from the connector. The machine harness connector J1 remains connected to the ECM.
Turn the disconnect switch and the keyswitch to the ON position.
Use the multimeter probes in order to make contact on the connector pins at the ECM. Measure the voltage at the ECM pins between contact J1-44 and contact J1-45.Expected Result:The voltage measurement is 8.0 0.5 DCV.Results:
OK - The voltage measurement is 8.0 0.5 DCV. The voltage is correct. The ECM power supply is correct. Turn the key start switch and the disconnect switch to the OFF position. Install the wires and sockets that were removed from the J1 connector back into the original locations. Proceed to Test Step 2.
NOT OK - The voltage measurement is greater than 8.0 0.5 DCV. The ECM power supply is not correct.Repair: Prior to replacing an ECM, always contact your dealership 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 SENSORS
Turn the keyswitch and the disconnect switch to the ON position.
One at a time, disconnect the sensors from the machine harness.
After disconnecting each sensor, check the status of the diagnostic code.Expected Result:The diagnostic code is no longer active.Results:
OK - The diagnostic code is not active when one of the sensors is disconnected. The harness circuit is correct. The sensor that was just disconnected has failed.Repair: Replace the sensor. Verify that the new sensor has corrected the problem.STOP
NOT OK - The diagnostic code is still active. The machine harness may be shorted to a ground source. Proceed to Test Step 3.Test Step 3. CHECK THE VOLTAGE AT THE SENSORS
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