OPERATOR AR 2027330 - Caterpillar

Illustration 1 g00641009
Schematic of the main pump pressure sensorThis diagnostic code is recorded when the implement ECM reads the signal from the main pump pressure sensor (wire M919-BU) as being shorted to the + battery. The sensor produces a PWM signal. The signal wire (M919-BU) connects to contact J1-52 of the implement ECM.Possible causes of the diagnostic code is listed:
The supply circuit (wire M931-YL) to the sensor is open, shorted to ground, or shorted high.
The return circuit (wire J764-BR) is open.
The signal circuit (wire M919-BU) is shorted to the + battery.
The signal circuit (wire M919-BU) is open or the sensor is disconnected.
The pressure sensor has failed.
The ECM has failed. This is unlikely.System Response:The machine response is a loss of the ripper auto stow function.Note: Ensure that CID 0597 FMI 03 is active. This procedure can cause new diagnostic codes to be recorded. Ignore these created diagnostic codes. When the procedure is completed, clear the created diagnostic codes.Test Step 1. CHECK THE VOLTAGE AT THE SENSOR.
Turn the disconnect switch and the key start switch to the ON position.
Disconnect the sensor from the machine harness.
At the machine harness connector for the sensor, measure the voltage between contact A (wire M931-YL) and contact B (wire J764-BR).Expected Result:The voltage should measure approximately 8 DCV.Results:
OK - The voltage is approximately 8 DCV. Proceed to test step 4.
NOT OK - The voltage is not approximately 8 DCV. Repair: There is an open in the machine harness or the ECM has failed. It is unlikely that the ECM has failed. Proceed to test step 2.Test Step 2. CHECK FOR AN OPEN IN THE SUPPLY CIRCUIT.
The key start switch and the disconnect switch remain in the ON position.
The sensor remains disconnected from the machine harness.
At the machine harness connector for the sensor, measure the voltage from contact A (wire M931-YL) to ground.Expected Result:The voltage should measure approximately 8 DCV.Results:
OK - The voltage measurement is approximately 8 DCV. Proceed to test step 3.
NOT OK - The voltage does not measure approximately 8 DCV.Repair: The supply circuit is not correct. Repair the circuit or replace the circuit.STOPTest Step 3. CHECK FOR AN OPEN IN THE RETURN CIRCUIT.
Turn the key start switch and the disconnect switch to the OFF position.
The sensor remains disconnected from the machine harness.
Disconnect the machine harness connector J1 from the implement ECM.
At the machine harness connector for the sensor, install a jumper wire from contact B (wire J764-BR) to ground.
At the machine harness connector for the ECM, measure the resistance from contact J1-9 (wire J764-BR) to ground.Expected Result:The resistance measurement should measure less than 5.0 ohms.Results:
OK - The resistance measurement is less than 5.0 ohms. The harness is correct.Repair: The ECM may have failed. It is unlikely that the ECM has failed. Recheck the status of the diagnostic code. If the diagnostic code remains present, exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, replace the implement ECM. See Testing and Adjusting, "Electronic Control Module (ECM) -