Powertrain
generic / SAE
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.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number1 / 21
Possible causes
- TPS contact track worn (older potentiometer-type sensors) high
- Carbon buildup blocking throttle plate medium
- Corroded TPS connector low
Symptoms
- Check engine light on
- Reduced throttle response, possible limp mode
- Hesitation or surging
- Idle too high or too low
Inspection / repair
- Difficulty: medium
- DIY: possible
- Estimated cost: 80–400 €
- Estimated time: 0.5–2.5 h
- Component: throttle position sensor
- Component: throttle body
- Component: accelerator pedal sensor
- MIL / check engine light
- emissions-relevant
- drive cycle required
- limp mode possible
Sources
References
sae:J2012