Exhaust Gas Recirculation: Testing and Inspection

DIAGNOSIS
An EGR flow check diagnosis of the digital EGR system is covered in Chart C-7 Exhaust Gas Recirculation (EGR) System Check. Testing and Inspection

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.