Cummins ISX CM870 (2003-06) Fault Code: 213 PID: P175 SPN: 175 FMI: 4/4 Engine Oil Temperature Sensor 1 Circuit – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the engine oil temperature circuit.

Possible causes:

1)Signal shorted to ground in the engine harness
2)Signal shorted to return or ground in the sensor.

Possible repairs:

1)Replace the engine coolant temperature sensor.
2)Replace the ECM.
3)Repair or replace the engine harness.