Exhaust Gas Recirculation: Testing and Inspection

EGR Valve Flow:

Too much EGR flow at idle, cruise, or cold operation may cause any of the following conditions to occur:

^ Engine stalls after cold start.
^ Engine stalls during closed throttle conditions.
^ Vehicle surges during cruise.
^ Rough idle.
^ DTC P0300 (misfire detected).

Too little or no EGR flow may allow combustion temperatures to get too high. This could cause the following symptoms:

^ Spark knock (detonation).
^ Engine overheating.
^ Emission test failure.

^ DTC P0401.
^ Poor fuel economy.

EGR flow diagnosis is included in the DTC P0401 diagnostic table. Pintle position error diagnosis is covered in DTC P1406. If EGR diagnostic trouble codes P0401 and/or P1406 are encountered, go to the DTC tables for diagnosis.