P0221: Throttle/Pedal Position Sensor/Switch "B" Circuit Range/Performance
P0221 means Throttle/Pedal Position Sensor/Switch "B" Circuit Range/Performance. The throttle position sensor (sensor "B") reports how far the throttle is open. On electronic throttle (drive-by-wire) systems, two or more sensors cross-check each other. The signal is inside its electrical limits, but it does not make sense compared with what the module expects from other sensors or from engine conditions (a "range/performance" fault). The part is often working electrically but reporting a wrong or implausible value.
Can I keep driving? Limit driving and diagnose promptly. Continued driving can cause damage, stalling or limp mode.
Common symptoms
- Check engine light and possibly the electronic throttle warning light
- Reduced power / limp mode
- Hesitation, surging or erratic idle
- Stalling
- Poor shift quality on automatic transmissions
Possible causes
- Failed throttle position sensor or throttle body
- Damaged connector, often from water or heat
- Wiring fault in the 5 V reference, ground or signal
- Accelerator pedal position sensor fault (on drive-by-wire)
How to diagnose P0221
- Check the sensor reading while slowly opening the throttle: it should rise smoothly with no dropouts.
- On drive-by-wire, compare both sensor signals.
- Check the connector and the 5 V reference.
- After throttle body work, perform the manufacturer's throttle relearn procedure.
What the code means, digit by digit
Generic codes have the same definition on every OBD-II vehicle (petrol cars from model year 1996 in the US, 2001 in the EU; diesels later). Manufacturers can add their own enhanced codes; those are not listed here.
Related codes
- P0220 Throttle/Pedal Position Sensor/Switch "B" Circuit
- P0222 Throttle/Pedal Position Sensor/Switch "B" Circuit Low
- P0223 Throttle/Pedal Position Sensor/Switch "B" Circuit High
- P0124 Throttle/Pedal Position Sensor/Switch "A" Circuit Intermittent
- P0123 Throttle/Pedal Position Sensor/Switch "A" Circuit High
- P0122 Throttle/Pedal Position Sensor/Switch "A" Circuit Low
- P0121 Throttle/Pedal Position Sensor/Switch "A" Circuit Range/Performance
- P0120 Throttle/Pedal Position Sensor/Switch "A" Circuit
General guidance only. Fault codes describe what the engine computer saw, not which part failed: confirm with testing before replacing parts, and follow the vehicle's service information.