COVER 4P9224 - Caterpillar

Illustration 1 g00504479
Schematic of the Pump Drive Pressure Sensor This diagnostic code is recorded when VIMS reads the voltage of the pump drive pressure sensor as being below normal. The voltage of the signal wire is below normal and/or shorted to ground. The sensor sends a PWM signal to the VIMS module. The possible causes of this diagnostic code are listed here:
The sensor has failed.
The signal circuit in the machine harness is shorted to ground.
The VIMS interface module has failed. This is unlikely.
CHECK THE SENSOR.
Turn the disconnect switch and the key start switch to the ON position.
Observe the status of the diagnostic code. Then disconnect the machine harness from the sensor.Expected Result: If the sensor is not the cause of the diagnostic code, the diagnostic code remains active. If the sensor has failed, the diagnostic code is NO longer active. Note: VIMS may wait up to approximately 30 seconds before updating the message area.Results:
OK - This diagnostic code remains active. The sensor is not causing the diagnostic code. The machine harness or the ECM may have failed. Proceed to 2.
NOT OK - This diagnostic code is NO longer active. The machine harness is correct and the ECM is operating properly. The sensor has failed. Replace the sensor. Refer to the Testing and Adjusting, "Pulse Width Modulated (PWM) Sensor -Test" section. STOP.
CHECK THE SIGNAL CIRCUIT FOR A SHORT TO GROUND.
The sensor remains disconnected from the machine harness.
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness from the VIMS interface module.
At the machine harness connector for the VIMS interface module, measure the resistance between the signal contact and frame ground.Expected Result: The resistance is greater than 5000 ohms.Results:
OK - Resistance is greater than 5000 ohms. The harness circuit resistance is correct. Proceed to 3
NOT OK - Resistance is less than 5000 ohms. The machine harness has failed. There is a short between frame ground and the signal circuit in the machine harness. Repair the machine harness or replace the machine harness. STOP.
CHECK IF THE DIAGNOSTIC CODE REMAINS.
Using established procedures, clean the contacts of the harness connectors.
Reconnect all harness connectors.
Turn the disconnect switch and the key start switch to the ON position.
Observe the status of the diagnostic code.
Operate the machine.
Observe the status of the diagnostic code.Expected Result: The diagnostic code CID0851 FMI 04 is no longer active.Results:
YES - Diagnostic code is NOT active. The diagnostic code does not exist at this time. The initial diagnostic code was probably caused by a poor electrical connection or a short at one of the harness connectors that was disconnected and then reconnected. Resume normal machine operation. STOP.
NO - Diagnostic code has not been corrected. It is unlikely that the ECM is faulty. Exit this CID/FMI procedure and perform this CID/FMI procedure again. If the cause of the fault is not found, then replace the VIMS interface module. See Testing And Adjusting, "Module - Replace". STOP.