Exhaust Gas Recirculation: Testing and Inspection

DIAGNOSIS
An EGR flow check diagnosis of the digital EGR system is covered in Chart C-7 EGR Flow Check.

RESULTS OF INCORRECT EGR SYSTEM OPERATION
With too much EGR flow at idle, cruise, or cold operation, any of the following conditions may occur:

- Engine stops after cold start.
- Engine stops at idle after deceleration.
- Car surges during cruise.
- Rough idle.

Too little or no EGR flow allows combustion temperatures to get too high. This could cause:

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