Closed Loop EGR Control At Limit Flow Too High
Same as P04D9 with the controller fully closing the actuator yet still measuring more EGR flow than required. The valve does not seat fully, or position feedback under-reads.
Affected components
- Egr valve a
- Egr position sensor a
Common causes
- High likelihood: Valve does not seat fully (debris or wear)
- Medium likelihood: Position sensor offset
Possible symptoms
- Check engine light on
- Pinging or knocking under load
- Power loss and hesitation
- Possible rough idle
- Failed emissions inspection (NOx)
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.