P0404Powertrain
Powertrain · SAE
EGR Control Circuit Range/Performance
Meaning
The EGR valve position/feedback signal is implausible: the actual position does not match what the ECU commanded. The valve is not moving as expected or is reporting its position incorrectly.
Common causes
- Faulty or mechanically sticking EGR valve
- Failed or imprecise EGR position sensor
- Carbon fouling obstructing the valve travel
- Wiring or connector with poor contact
- Worn electric drive/motor of the valve
Symptoms
- Rough idle
- Knock or pinging under load
- Hesitation and power loss
- Possible rise in emissions
- Check-engine light on
Severity
Moderate: degraded drivability and possible knock, but no risk of immediate damage.
What to do
- Compare commanded and actual EGR valve position live
- Clean the EGR valve and confirm it moves freely through its full travel
- Inspect the position sensor wiring and connector
- Replace the valve or sensor if the position stays inconsistent