OBD-II code · Powertrain (generic)
P0121 Throttle/Pedal Position Sensor "A" Range/Performance
The throttle position sensor (TPS) signal does not match the expected range for the commanded pedal position. On drive-by-wire vehicles, two redundant sensors are compared; a divergence between them or implausible motion triggers this code.
Is it safe to drive with P0121?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyTPS contact track worn (older potentiometer-type sensors)
- PossibleCarbon buildup blocking throttle plate
- Less likelyCorroded TPS connector
Symptoms
- Check engine light on
- Reduced throttle response, possible limp mode
- Hesitation or surging
- Idle too high or too low
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2.5 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Throttle Position Sensor, Throttle Body, Accelerator Pedal Sensor
Related codes
- P2121Throttle/Pedal Position Sensor "C" Range/Performance
- P2131Throttle/Pedal Position Sensor "E" Range/Performance
- P011EEngine Coolant Temperature 1 / Ambient Air Temperature Correlation
- P011FEngine Coolant Temperature 2 / Ambient Air Temperature Correlation
- P0120Throttle Position Sensor / Switch A Circuit Malfunction
- P0122Throttle/Pedal Position Sensor "A" Low Input
- P0123Throttle/Pedal Position Sensor "A" High Input
- P0124Throttle/Pedal Position Sensor "A" Circuit Intermittent
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.