BLOCK AS- 1548789 - Caterpillar

Illustration 1 g01254820
5 VDC Power Supply connections
This diagnostic code is associated the 5 volt power supply of the ECM. The 5 volt power supply provides power for the discharge pressure sensor of the main hydraulic pump .The CID 0262 FMI 04 diagnostic code is recorded when the ECM reads the voltage of the sensor supply circuit and the voltage is below normal.The following conditions could cause this diagnostic code:
A sensor has failed.
The sensor supply circuit is shorted to a ground 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 SENSOR
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the main hydraulic pump discharge pressure sensor from the machine harness.
After disconnecting the sensor, check the status of the CID 262 FMI 04 diagnostic code. Expected Result:The CID 262 FMI 04 diagnostic code is no longer active.Results:
OK - The diagnostic code is not active. The harness circuit is correct. The sensor that was just disconnected has failed.Repair: Replace the sensor. Verify that the new sensor corrected the problem before operating the machine.STOP
NOT OK - The diagnostic code is still active. The sensor is not causing the problem. 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 the 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 ECM pins between the contact J1-11 (power supply) and the contact J1-21 (return). 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 less 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