Circuit DescriptionThe exhaust gas recirculation (EGR) differential pressure sensor has two ports that sense exhaust gas pressure. The sensor outputs a voltage which represents the pressure difference between the two ports. The electronic control module (ECM) uses this pressure to determine how much exhaust gas is flowing through the EGR connection tube to the intake manifold. This information is used to control the EGR valve for correct emission levels.

The ECM provides a 5 volt supply to the EGR differential pressure sensor on the sensor supply circuit. The ECM also provides a ground on the sensor return circuit. The EGR differential pressure sensor provides a signal to the ECM on the EGR differential pressure sensor signal circuit. This sensor signal voltage changes, based on the differential pressure in the EGR crossover tube.

Component LocationThe EGR differential pressure sensor is located on the intake side of the engine.

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

Conditions for Setting the Fault CodesThe ECM detects that the EGR differential pressure signal voltage is greater than 4.8-VDC for more than 8 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.A default value for the EGR differential pressure sensor is used.Diesel exhaust fluid injection into the aftertreatment system is disabled.Active and stationary regeneration of the diesel particulate filter will be disabled.The EGR valve will be closed.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, 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 after the diagnostic runs and passes.For OBD engines, the ECM will turn off the 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:

An open return circuit in the engine harness, connectors, or sensorA signal wire shorted to sensor supply or battery voltageA damaged EGR differential pressure sensor.

Possible Cause:1) ECM failure2) Engine Harness