Exhaust Gas Recirculation: Testing and Inspection

An EGR flow check diagnosis of the linear EGR system is covered by DTC PO4O1. Pintle position error diagnosis is covered by DTC P1406. If EGR diagnostic trouble codes P0401 and/or P1406 are encountered, refer to Diagnostic Charts. Testing and Inspection

Results of Incorrect EGR System Operation
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 at idle after deceleration.
^ 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:

^ Spark knock (detonation).
^ Engine overheating.
^ Emission test failure.
^ DTC P0401 (EGR flow test).
^ Poor fuel economy.