SENSOR GP- 1619933 - Caterpillar

Illustration 1 g01920813
Schematic of the "Main Pump Pressure" sensor
Note: The sensor does not connect directly to frame ground. The sensor connects to the return circuit of the Machine ECM. The ECM connects the return wire to the frame ground internally.This diagnostic code is recorded when the ECM reads the sensor signal as being above normal. There is a short to the + 24 v sensor power supply.The possible causes of this diagnostic code are listed below:
The sensor power supply (wire 147-PU(Purple)) from the electrical system to the sensor is open.
The return circuit (wire A209-BK(Black)) is open.
The signal circuit (wire C472-GN(Green)) is open or the sensor is disconnected.
The signal circuit is shorted to the + 24 v sensor power supply.
The sensor has failed.
The ECM has failed. A failure of the ECM is unlikely. Note: Ensure that the CID 0864 FMI 03 diagnostic code is present.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the original diagnostic code 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 sensor from the machine harness.
At the machine harness connector for the sensor, measure the voltage between contact A (wire 147-PU(Purple)) and contact B (wire A209-BK(Black)). Expected Result:The voltage measurement should be approximately battery voltage.Results:
OK - The voltage is approximately 24 DCV. Proceed to Test Step 4.
NOT OK - The voltage measurement is NOT 24 DCV. Repair: There is an open in the machine harness or the ECM has failed. A failure of the Machine ECM is unlikely.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 1 (wire 147-PU(Purple)) to ground. Expected Result:The voltage measurement should be approximately 24 DCV.Results:
OK - The voltage measurement is approximately 24 DCV. Proceed to Test Step 3.
NOT OK - The voltage measurement is NOT 24 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 ECM.
At the machine harness connector for the sensor, install a jumper wire from contact B (wire A209-BK(Black)) to ground.
At the machine harness connector for the ECM, measure the resistance from contact J1-18 (wire A209-BK(Black)) to ground. Expected Result:The resistance measurement should measure less than 5 ohms.Results:
OK - The resistance measurement is less than 5 ohms. The harness is correct.Repair: The ECM may have failed. A failure of the ECM is unlikely. 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