Powertrain, generic · Fuel and air metering (injector circuit)
P0239 Turbocharger/Supercharger Boost Sensor B Circuit
Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible
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.
Likely causes
Connector or wire to sensor B open or corroded
Sensor B faulty or oily
Shared 5 V reference or ground disturbed
Engine module
Symptoms
- Check engine light on
- Loss of power, limp mode
- Uneven boost build-up on twin turbos
Repair estimate
DifficultyEasyDIY possible
Parts and labour€30–250
Time0.5–2 h
Typical range across vehicles; the real cost depends on what the testing finds.
Parts involved
boost pressure sensor bsensor wiringcharge air hoses
Related codes
References: law.cornell.edu, en.wikipedia.org, en.wikipedia.org.