P04D8
Excessive Time To Enter Closed Loop EGR Control
Generic OBD-II
Common symptoms
What you'll notice
- Check and clean the EGR valve and passages
- Inspect and repair any vacuum leaks in the EGR system
- Replace the EGR valve if necessary
- Perform a thorough engine tune
- up, including spark plug replacement and fuel system cleaning
- If all else fails, check the engine control module (ECM) for any error codes or malfunctions
Common causes
Most likely first
- Faulty EGR valve
- Clogged EGR passages
- Malfunctioning EGR control solenoid
- Engine vacuum leak
- Dirty or malfunctioning mass airflow sensor
How to diagnose & fix
Work through it in order
- Engine hesitation or rough idle
- Decreased fuel efficiency
- Engine stalling or misfiring
- Reduced engine power or acceleration
- Check engine light illuminated
Read & clear P04D8 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.