P02E8Diesel Intake Air Flow A Position Sensor Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- 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. P02E8 means the position signal is below its range – a signal wire shorted to ground or an open 5 V supply or signal wire. GM's LML sets it below 0.40 V for 5 s in the first trip, newer GM diesels with digital sensors below 1–5 % of 5 V after two trips; Ford's diesels below 0.08 V for 3 s. On a fault the valve is switched off and the spring opens it: driving is usually little affected, but EGR control is restricted and filter regeneration may be blocked.
- What you may notice
- Check engine light on
- Often no noticeable change
- Filter regeneration does not run, soot load rises
- Likely causes
- LikelySignal wire shorted to ground or 5 V supply open
- PossibleSensor faulty
- PossibleConnector corroded
- Rare5 V reference loaded by another sensor
- 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 – €500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.