P0221
Throttle/Pedal Position Sensor/Switch "B" Range/Performance
The B channel of the throttle or pedal position sensor reports values that do not correlate with the A channel or with engine load. Often caused by mechanical wear in the resistive track or by a sticking pedal/throttle plate.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Symptoms
- Check engine light on
- Reduced throttle response, possible limp mode
- Hesitation or surging
- Idle too high or too low
Common causes
Ordered by how often each turns out to be the cause.
- Resistive track wornCommon
- Throttle plate stickingPossible
- Sensor element aged beyond calibration windowLess likely
Parts involved
- Throttle Position Sensor B
- Throttle Body
P0221 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.