Cummins ISM CM870 (2003-06) Fault Code: 135 PID: P100 SPN: 100 FMI: 3/3 Engine Oil Rifle Pressure 1 Sensor Circuit – Voltage Above Normal or Shorted to High Source. High signal voltage detected at the engine oil pressure circuit.

If the oil pressure sensor shares supply and return wires in the engine harness with other sensors, opens and shorts in the engine harness can cause multiple fault codes to be active. Before troubleshooting Fault Code 135, check for multiple faults.

Possible causes:

1)Open return circuit in the harness, connectors, or sensor
2)A signal circuit shorted to sensor supply or battery voltage.

Possible repair:

1)Replace the ECM
2)Repair or replace the engine harness
3)Replace the engine oil pressure sensor.