Circuit DescriptionThe engine control module (ECM) provides a 5 volt supply to the EGR orifice pressure sensor on the sensor supply circuit. The ECM also provides a ground on the sensor return circuit. The EGR orifice pressure sensor provides a signal to the ECM on the EGR orifice pressure sensor signal circuit. This sensor signal voltage changes based on the pressure at the EGR orifice pressure sensor.

Component LocationThe EGR orifice pressure sensor is mounted on the EGR mass measurement assembly near the EGR differential pressure sensor.

Conditions for Running the DiagnosticsThis diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running.

Conditions for Setting the Fault CodesThe Engine Control Module (ECM) detected the EGR orifice pressure sensor signal voltage was less than 0.25 volts for 5 seconds.

Action Taken When the Fault Code is ActiveThe ECM illuminates the amber CHECK ENGINE lamp and/or the Malfunction Indicator Lamp (MIL) immediately when the diagnostic runs and fails.Exhaust Gas Recirculation (EGR) valve operation will be disabled.Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.Conditions for Clearing the Fault CodeTo validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.For On-Board Diagnostics (OBD) engines, the ECM will extinguish the Malfunction Indicator Lamp (MIL) after three consecutive trips where the diagnostic runs and passes.The Reset All Faults command in INSITE™ electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop TalkPossible causes of this fault include:

Signal circuit open or shorted to ground in the engine harness or sensorSupply line open or shorted to ground.

Possible Cause:1) ECM failure2) Engine harness