What it means
The Turbocharger/Supercharger Speed Sensor A Circuit Range/Performance code indicates that the sensor signal is outside expected range or performance. The code alone does not identify the cause.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Turbo or supercharger speed sensor A reports how quickly the forced-induction unit’s rotating assembly is turning. The engine controller compares its signal with expected speed information and sets this code when sensor A’s reading is implausible or outside its expected operating pattern.
Common causes
Most likely first.
- Oil-contaminated sensor tip
- Aged Hall element
- Sensor element aged beyond calibration window
Symptoms
- Check engine light
How to diagnose it
- Record freeze-frame data and compare sensor A’s live speed reading with engine speed and boost data to see when the mismatch occurs.
- Inspect speed sensor A and its tip for oil contamination, damage, or looseness that could distort the reading.
- Check the sensor A connector and nearby wiring for oil ingress, corrosion, poor pin fit, or heat damage.
- Use the vehicle wiring diagram to check sensor A’s supply, ground, and signal circuits for continuity and shorts.
- If the wiring checks out, test sensor A’s output against the manufacturer’s specification to confirm whether its sensing element is out of calibration.
Common fixes
- Clean oil contamination from sensor A’s tip if the manufacturer permits cleaning.
- Repair poor connections or damaged wiring at the sensor A connector.
- Correct an oil leak that is contaminating sensor A.
- Replace speed sensor A if its output remains outside specification.
Can I keep driving?
With only the check-engine light and no change in performance, gentle driving to a repair location is generally reasonable. Avoid sustained high boost or heavy acceleration, since an unreliable turbo-speed reading may limit the controller’s ability to protect the turbocharger or supercharger.
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.