What it means
The wastegate position sensor B signal does not correlate with the commanded actuator position within tolerance. Sensor offset, mechanical wear, or signal integrity degraded.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
Wastegate position sensor B reports the position of the wastegate actuator on the B control path. This code sets when sensor B's position signal fails to match the commanded actuator position within the allowed range, which can impair boost regulation.
Common causes
Most likely first.
- Sensor mechanically offset from actuator
- Linkage between sensor and wastegate worn
Symptoms
- Check-engine light
- Reduced engine power
- Weak acceleration or slower turbo response
How to diagnose it
- Record freeze-frame data and compare commanded wastegate position with sensor B's live reading to identify the operating conditions for the mismatch.
- Inspect sensor B's connector and harness for loose pins, corrosion, heat damage, and chafing around the turbocharger.
- With the engine off and safe access, check the B-side wastegate linkage for wear, looseness, binding, or sensor misalignment.
- Test sensor B's reference, ground, and signal circuits through the actuator's operating range and compare results with the manufacturer's specification.
- If the circuit checks pass, test sensor B and its linkage for smooth, repeatable position feedback.
Common fixes
- Secure sensor B's connector or repair damaged wiring.
- Realign sensor B if it has shifted and adjustment is allowed by the manufacturer's procedure.
- Repair worn or loose B-side wastegate linkage.
- Replace sensor B if it continues to report an inaccurate position with good wiring and correct alignment.
Can I keep driving?
Expect reduced power or slower turbo response, which can make merging and overtaking harder; avoid hard acceleration and heavy loads. Have the boost-control fault diagnosed soon because continued incorrect boost regulation can worsen performance.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.