Cummins ISX CM870 (2003-06) Fault Code: 2274 PID: P411 SPN: 411 FMI: 4/4 Exhaust Gas Recirculation Valve Delta Pressure Sensor Circuit – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the EGR differential pressure sensor circuit.

The EGR differential 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 2274, check for multiple faults.

Possible causes:

1)Signal circuit open in the engine harness, connectors, or sensor
2)Supply circuit open or shorted to ground
3)Leaks in the sensor EGR differential pressure tubes
4)Sensor shorted to ground.

Possible repairs:

1)Repair the exhaust leaks at the pressure tubes.
2)Replace the EGR differential pressure sensor.
3)Repair the damaged harness, connector, or pins.
4)Replace the ECM.