CHANNEL 6G6318 - Caterpillar

Illustration 1 g01254820
5 VDC Power Supply connections
This diagnostic code is associated the ECM 5V power supply. The 5V power supply provides power for the main hydraulic pump discharge pressure sensor.The CID 0262 FMI 03 diagnostic code is activated when the ECM detects that the voltage of the 5V power supply circuit is higher than normal.The following conditions could cause this diagnostic code:
The power supply circuit is shorted to a higher voltage source.
The ECM has failed. This 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, that all connections are secure and that all connections 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. Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the problem has been corrected.Test Step 1. CHECK THE VOLTAGE AT THE SENSOR
Turn the disconnect switch and the key start switch to the ON position.
Disconnect the machine harness connector from the main hydraulic pump discharge pressure sensor.
At the machine harness connector for the sensor, measure the voltage from contact A (wire 997-OR(Orange)) to contact B (wire 998-BR(Brown)). Expected Result:The voltage measurement is 5.0 0.5 DCV.Results:
OK. - The voltage measurement is 5.0 0.5 DCV. The voltage is correct. Proceed to Test Step 4.
NOT OK. - The voltage measurement is greater than 5.0 0.5 DCV. The measurement is not correct. Proceed to Test Step 2.Test Step 2. 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 151-6320 Removal Tool to remove the supply wire and the socket at contact J1-11 (wire 997-OR(Orange)) and the return wire and socket at contact J1-21 (wire 998-BR(Brown)) from the connector. The machine harness connector J1 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 connector pins of the ECM. Measure the voltage at the pins of the ECM between the power contact J1-11 and the return contact J1-21. Expected Result:The voltage measurement is 5.0 0.5 DCV.Results:
OK. - The voltage measurement is 5.0 0.5 DCV. The voltage is correct. The ECM power supply is correct. Install the wires and sockets that were removed from the J1 connector back into the original locations. Proceed to Test Step 3.
NOT OK. - The voltage measurement is greater than 5.0 0.5 DCV. The ECM power supply is not correct.Repair: Prior to replacing an ECM, always contact your dealership's Technical Communicator for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM requires replacement, refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace".STOPTest