Cummins ISB CM850 (2003-06) Fault Code: 141 (Marine) PID: 100 SPN: 100 FMI: 4 Oil Pressure Sensor Circuit – Voltage Below Normal, or Shorted to Low Source. Low signal voltage detected at the engine oil pressure circuit.

Possible causes:

1)Signal circuit open or shorted to ground in the engine harness or sensor
2)Supply line open or shorted to ground.

Possible repairs:

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