ALTERNATOR & COMPRESSOR MOUNTING GROUP 4W4386 - Caterpillar

Illustration 1 g02139243
The "Hydraulic Pump 1 Outlet Pressure Sensor" is on the left side of the main control valve.
Illustration 2 g02037937
Schematic of the "Hydraulic Pump 1 Outlet Pressure Sensor"
This diagnostic code is associated with the "Hydraulic Pump 1 Outlet Pressure" Sensor. This diagnostic code is recorded when the Machine ECM reads the frequency of the signal and the frequency is not within an expected range.Note: Before performing the following procedure, ensure that the diagnostic code for this procedure is active.The possible causes of this diagnostic code are listed below:
The sensor has failed.
Intermittent connections or poor connectionsTest Step 1. CHECK THE +8 DCV SUPPLY VOLTAGE
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness connector from the sensor.
Turn the disconnect switch and the key start switch to the ON position.
At the machine harness connector for the sensor, measure the voltage (DCV) between contact 1 (wire J850-WH(White)) and contact 2 (wire 235-BK(Black)).
At the machine harness connector for the sensor, measure the voltage (DCV) between contact 1 (wire J850-WH(White)) and frame ground. Expected Result:The voltage is 8 0.5 DCV for both measurements.Results:
OK - The voltage is 8 0.5 DCV for both measurements. The voltage is correct. Proceed to Test Step 2.
NOT OK - The voltage is NOT 8 0.5 DCV for both measurements. The voltage is not correct. The Machine ECM has failed or the harness has failed.Repair: A failure of the ECM is unlikely. Verify the harness. If the harness is correct, replacement of the Machine ECM may be needed.STOPTest Step 2. VERIFY THE GROUND OF THE SENSOR
At the machine harness connector of the sensor, place a jumper between contact 2 (wire 235-BK(Black)) and frame ground.
At the machine harness connector J1, measure the resistance between the contact J1-14 (wire 235-BK(Black)) and frame ground.
At the machine harness connector J1, measure the resistance between the contact J1-2 (wire 235-BK(Black)) and frame ground. Expected Result:The resistance is less than 5 ohms for each circuit.Results:
OK - The resistance is less than 5 ohms. The circuit resistance is correct. Proceed to Test Step 3.
NOT OK - The resistance is greater than 5 ohms. The circuit resistance is not correct. The harness is open.Repair: Repair or replace the machine harness.STOPTest Step 3. CHECK THE SENSOR SIGNAL CIRCUIT
Remove the jumper that was placed in the previous test.
At the machine harness connector of the sensor, place a jumper between contact 3 (wire K904-GN(Green)) and frame ground.
At the machine harness connector J1, measure the