PACCAR PX-8 CM2150 (2007-09) Fault Code: 2274 PID: 411 SPN: 411 FMI: 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.

Verify the electronic control module (ECM) calibration is correct. Check the calibration revision history found on QuickServe® Online for applicable fixes to the calibration stored in the ECM. If necessary, recalibrate the ECM.

Possible causes:

1)A signal circuit open or shorted to ground in the engine harness or sensor
2)A supply wire open or shorted to ground
3)A malfunctioning EGR differential pressure sensor.

Possible repairs:

1)Replace the ECM.
2)Replace the EGR valve delta pressure sensor.
3)Replace the engine harness. Refer to Procedure 019-043 (Engine Wiring Harness) in Section 19.
4)Repair the OEM harnessVerify the electronic control module (ECM) calibration is correct. Check the calibration revision history found on QuickServe® Online for applicable fixes to the calibration stored in the ECM. If necessary, recalibrate the ECM.

Possible causes:

1)A signal circuit open or shorted to ground in the engine harness or sensor
2)A supply wire open or shorted to ground
3)A malfunctioning EGR differential pressure sensor.

Possible repairs:

1)Replace the ECM.
2)Replace the EGR valve delta pressure sensor.
3)Replace the engine harness. Refer to Procedure 019-043 (Engine Wiring Harness) in Section 19.
4)Repair the OEM harness