P0239Turbocharger/Supercharger Boost Sensor B Circuit
- 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 B is a second boost pressure sensor, for a second turbo or bank on parallel twin-turbo engines or a second stage on two-stage systems. No manufacturer using sensor B codes was found – GM, Ford and Saab, even on two-stage and twin-turbo engines, use a single boost sensor; the description follows CARB and the documented sensor A codes. P0239 is the general circuit fault of sensor B, the counterpart of P0235, without telling low, high or range apart. As with sensor A, boost control would be switched off, with loss of power.
- What you may notice
- Check engine light on
- Loss of power, limp mode
- Uneven boost build-up on twin turbos
- Likely causes
- LikelyConnector or wire to sensor B open or corroded
- PossibleSensor B faulty or oily
- RareShared 5 V reference or ground disturbed
- RareEngine module
- 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 – €250
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.