Closed Loop EGR Control At Limit Flow Too Low
With EGR running in closed loop the controller has driven the actuator to its maximum opening but cannot reach the required EGR flow. The valve, cooler, or pipework is restricted enough that even full open does not deliver the modelled rate.
Affected components
- Egr valve a
- Egr cooler a
- Egr pipework
Common causes
- High likelihood: EGR cooler clogged with soot
- Medium likelihood: Valve effective opening reduced by carbon
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.