Cummins ISB CM850 (2003-06) Fault Code: 2271 PID: 27 SPN: 27 FMI: 3 Exhaust Gas Recirculation (EGR) Valve Position Sensor Circuit – Voltage Above Normal or Shorted to High Source. High signal voltage detected at the EGR valve position sensor circuit.

The EGR valve position sensor shares Supply and Return wires in the engine harness with other sensors. Open circuits and short circuits in the engine harness can cause multiple fault codes to be active.

Possible causes:

1)Open return in the harness, connectors, or sensor
2)SIGNAL wire shorted to sensor supply or battery voltage
3)Failed EGR valve position sensor
4)Failed ECM.

Possible repairs:

1)Replace the EGR valve assembly.
2)Repair or replace the engine harness.
3)Replace the engine control module.