P0236Turbocharger/Supercharger Boost Sensor A Circuit Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- Boost sensor A measures the absolute pressure between charge air cooler and throttle – GM calls it TIAP, Ford TIP – usually combined with an intake air temperature sensor; its voltage rises with pressure. With the ignition on and the engine stopped it must read the same as manifold and barometric pressure. P0236 is the plausibility fault: the signal is electrically valid but wrong. After a stop of at least 10 s boost, manifold and barometric pressure must match (Ford within about 7–9 kPa); while running, GM compares the sensor with models from airflow, manifold pressure and throttle and flags deviations such as more than 30 kPa from manifold pressure – with the warning light in the first trip. A charge air leak often triggers it too, because the model comparison drifts apart. VW traced a Tiguan case to contact resistance in a harness connector. With a sensor fault boost control is switched off and only the base boost of the wastegate spring remains, with a clear loss of power.
- What you may notice
- Check engine light on
- Loss of power, only base boost
- Hissing or whistling with a leak
- Likely causes
- LikelyCharge air leak (hose, clamp, cooler) between turbo and throttle
- LikelyBoost sensor dirty, oily or drifting
- PossibleContact resistance in connector or harness
- PossibleManifold or barometric sensor faulty (correlation partner)
- RareIce or condensate in the charge air cooler in cold weather
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €30 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.