Circuit DescriptionThe exhaust gas recirculation (EGR) temperature sensor is a variable resistor sensor and is used to measure the temperature of the EGR gas flow after it exits the EGR cooler. The engine control module (ECM) supplies 5 volts to the EGR temperature signal circuit. The ECM monitors the change in voltage caused by changes in the resistance of the sensor to determine the EGR flow temperature.

The EGR temperature value is used by the ECM for the engine protection system and engine emissions control.

Component LocationThe EGR temperature sensor is located on the EGR connection tube between the EGR cooler and the air intake connection.

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 temperature was greater than 210°C [410°F] for more than 5 seconds.

Action Taken When the Fault Code is ActiveThe ECM logs the fault code immediately when the diagnostic runs and fails.Engine torque will be reduced.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 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:

Plugged or restricted EGR differential pressure sensor portsDamaged EGR differential pressure tubesA malfunctioning EGR valveA low reading from the EGR differential pressure sensorA low reading for the EGR valve position sensorHigh exhaust temperaturesLow coolant levelHigh coolant temperatureAn incorrect coolant/water mixtureA stuck closed variable geometry turbochargerA fouled EGR cooler.Note: This fault code will most likely not be active with no load in the shop. The engine must be loaded to trigger this fault code.

Possible Cause:1) EGR temperature sensor failure2) Coolant level3) EGR cooler failure4) ECM calibration