OBD2 code P0404: EGR A Control Circuit Range/Performance
Exhaust gas recirculation (EGR) routes part of the exhaust back into the intake to lower combustion temperature and NOx.
Detected Root Component
EGR Valve
Technical Component Diagrams
EGR Valve Layout
Diag Expert technical diagram
EGR Valve Connector
Diag Expert technical diagram
Observed Symptoms
- Check engine light on
- EGR deactivated
- Rough idle or jerking if the valve hangs open
- Diesel: possibly reduced power
Possible Causes
- Valve coked or stiff
- Valve drive (motor, gear) worn
- Position sensor in the valve inaccurate
- Supply voltage too low or ground fault
Tools Required
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Parts likely to be the cause (Vanne EGR)
Vanne EGR
Photo d'illustration : Vanne EGR
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Frequently asked questions about code P0404
What does code P0404 mean? ▾
OBD2 code P0404: EGR A Control Circuit Range/Performance. Exhaust gas recirculation (EGR) routes part of the exhaust back into the intake to lower combustion temperature and NOx.
What are the symptoms of code P0404? ▾
Code P0404 may cause: Check engine light on, EGR deactivated, Rough idle or jerking if the valve hangs open, Diesel: possibly reduced power. The intensity of these symptoms varies depending on the vehicle and driving conditions.
What causes code P0404? ▾
The most common causes of code P0404 are: Valve coked or stiff, Valve drive (motor, gear) worn, Position sensor in the valve inaccurate, Supply voltage too low or ground fault. A proper OBD2 diagnostic will pinpoint the exact cause.
Is it serious to drive with code P0404? ▾
Code P0404 has moderate severity (Warning). Short-term driving remains possible, but a prompt check is recommended to prevent worsening.
How do I fix code P0404? ▾
Start by reading the code with an OBD2 scanner, then follow the interactive decision tree on this page. Priority causes to check: Valve coked or stiff, Valve drive (motor, gear) worn, Position sensor in the valve inaccurate, Supply voltage too low or ground fault. Difficulty: Medium · Estimated time: 30-60min.