Powertrain, generic · Fuel and air metering (injector circuit)

P0236 Turbocharger/Supercharger Boost Sensor A Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

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.

Likely causes

Charge air leak (hose, clamp, cooler) between turbo and throttle
Boost sensor dirty, oily or drifting
Contact resistance in connector or harness
Manifold or barometric sensor faulty (correlation partner)
Ice or condensate in the charge air cooler in cold weather

Symptoms

  • Check engine light on
  • Loss of power, only base boost
  • Hissing or whistling with a leak

Repair estimate

DifficultyEasyDIY possible
Parts and labour€30–300
Time0.5–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

boost pressure sensor asensor wiringcharge air hoses

Related codes

P0237P0238P025EP023DP0106P2227

References: law.cornell.edu, gsi.ext.gm.com, fordservicecontent.com, saabwisonline.com.