What it means
The turbocharger actuator position sensor reports a value, but it does not track commanded vane or wastegate position within tolerance. Often a sticky VTG mechanism due to soot.
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
The turbocharger boost control position sensor A reports actuator movement so the engine control module can compare actual position with the commanded vane or wastegate position. This code sets when the reported position does not track the command consistently within the module's tolerance, which can happen if variable-geometry vanes stick from soot or the linkage or sensor is worn.
Common causes
Most likely first.
- VTG vanes coked, sticky
- Actuator linkage worn
- Sensor element aged beyond calibration window
Symptoms
- Check-engine light
- Reduced engine power or acceleration
- Poor boost response
How to diagnose it
- Save freeze-frame data, then graph commanded and actual sensor A positions during a controlled change in engine load to see when tracking diverges.
- Inspect the actuator linkage and its connections for looseness, wear, binding, or damage that could prevent the vanes or wastegate from following commands.
- Check the actuator and sensor wiring and connector for corrosion, chafing, loose pins, or intermittent contact.
- With the engine off and using the vehicle's approved procedure, check whether the linkage moves freely through its range without sticking.
- If linkage movement and wiring are sound, test sensor A and actuator response against the manufacturer's specification, then assess the turbo mechanism for soot-related sticking.
Common fixes
- Repair loose or worn actuator linkage.
- Clean or service sticking variable-geometry vanes using the vehicle's approved procedure.
- Repair intermittent wiring or connector contact at sensor A or the actuator.
- Replace the position sensor or actuator assembly if its signal no longer tracks within specification.
Can I keep driving?
The vehicle may enter reduced-power mode, so avoid hard acceleration, towing, and long trips until boost response is reliable. Continued driving with a sticking turbo mechanism can worsen power loss and may lead to further turbo or engine-control problems.
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.