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 is a two part diagnostic.

One part runs immediately after the keyswitch is turned OFF, and the engine coolant temperature is above 70°C or 158°F.

The second part runs continuously while the engine is running.Conditions for Setting the Fault CodesThe Engine Control Module (ECM) detected the EGR orifice pressure sensor was not changing with engine conditions or was incorrect at key OFF.

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 using a Diagnostic Road Test, utilize a route that incorporates both stop and go city type driving and steady state highway type driving. It may be necessary to load the unit for certain diagnostics in the ECM to run.To validate the repair using a Chassis Dynamometer, utilize a routine that incorporates acceleration and motoring events, steady state highway type operation, and load. This will simulate normal driving and allow the diagnostics in the ECM to run.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 code include:

A damaged EGR orifice pressure sensorHigh resistance in the wiring harness on the signal or return wirePlugged or restricted EGR differential pressure sensor flow ports.

Possible Cause:1) ECM calibration