P02E4Diesel Intake Air Flow A Control Stuck Open
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- The diesel intake air flow valve A is the throttle flap ahead of the intake manifold of a diesel engine: it creates the vacuum needed for high EGR rates, lowers airflow to heat the particulate filter and catalyst during regeneration and closes at switch-off against run-on shaking. A spring holds it open when unpowered; an electric motor positions it, with a position sensor reporting back. P02E4 means the valve stays more open than commanded, so the EGR rate and regeneration heating cannot be achieved. GM sets it when the valve is over 8 % more open than commanded although the motor pushes at more than 80 % duty, for about 4 s, with the warning light in the first trip; Ford's diesels at more than 15 % deviation for 25 s, also during the cold-start strategy. Driving is barely affected, but NOx and soot rise.
- What you may notice
- Check engine light on
- Regeneration aborts, soot load rises
- Shaking at switch-off, little loss of power
- Likely causes
- LikelyCoking or oil carbon preventing closing
- PossibleReturn spring or gear faulty, flap loose on the shaft
- PossibleMotor too weak (wear)
- RareForeign object or ice
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €50 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.