What it means
The position feedback sensor on the variable-geometry or wastegate turbocharger actuator is not communicating or is implausible. Without position feedback, boost control runs in default mode and power is reduced.
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
Turbocharger boost control position sensor A measures the wastegate or variable-geometry actuator position so the engine module can compare actual movement with its command. This code sets when sensor A’s feedback is outside the expected range or does not respond plausibly, and the module may limit boost as a result.
Common causes
Most likely first.
- Position sensor failed
- Wiring open or chafed near turbo
Symptoms
- Check-engine light
- Reduced engine power or acceleration
- Poor boost response
How to diagnose it
- Save freeze-frame data and compare commanded turbo actuator position with sensor A live feedback to see when they diverge.
- Inspect the actuator and sensor A wiring near the turbo for heat damage, chafing, loose connectors, or corrosion.
- Check the actuator linkage for binding or excessive movement that could keep the sensor from tracking its position.
- Check related boost-control codes and inspect charge-air hoses for leaks that could affect the system context.
- Test sensor A signal response through actuator movement and verify the circuit against the manufacturer's specification.
Common fixes
- Repair chafed, heat-damaged, or loose wiring at sensor A.
- Secure or repair corroded terminals and connector seals.
- Free or repair a binding wastegate or variable-geometry actuator linkage if confirmed.
- Replace sensor A or the actuator assembly if its feedback fails the specified test.
Can I keep driving?
Because the engine may enter reduced-power operation, avoid hard acceleration, towing, and long trips until boost control is restored. Stop safely if power loss or unusual turbo noise makes continued driving unsafe.
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.