Cummins ISX CM870 (2003-06) Fault Code: 2271 PID: P27 SPN: 27 FMI: 3/3 EGR Valve Position Sensor Circuit – Shorted High. High signal voltage detected at EGR valve position sensor circuit.

The EGR valve position sensor shares supply and return wires in the engine harness with other sensors. Opens and shorts in the engine harness may cause multiple fault codes to be active.

Possible causes:

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

Possible repairs:

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