The computer sees too much EGR flow. The driver may notice rough idle, stalling or hesitation.
Likely causes, most common first
- EGR valve stuck open
- Carbon holding the valve open
- Faulty control solenoid
- Faulty EGR sensor
Parts usually involved
- EGR valve
- Control solenoid
- EGR passages
Test before you replace
Check whether the valve seats fully closed at idle and inspect it for carbon.
General guidance for generic OBD2 codes. Always follow the maker's procedure for the car in front of you.