Trouble codes › P0121
P0121 Throttle/Pedal Position Sensor/Switch "A" Circuit Range/Performance
Throttle
P0121 means throttle position sensor A's reading doesn't match the other sensors, often a worn sensor or a dirty throttle body.
The throttle position sensor A reading doesn't fit with other sensors (such as airflow and engine speed), or changes in a way that doesn't make sense.
The engine may hesitate or go into reduced power. Drive carefully and get it fixed soon.
Common causes
- A worn throttle position sensor with a dead spot
- A dirty throttle body
- Wiring or connector problems
Symptoms
- Hesitation or stumbling
- Erratic idle
- Reduced power on some vehicles
Known problems: Ford electronic throttle body problems (2009-2013)
What to check first
- Watch the throttle position reading while slowly opening the throttle; look for jumps or dropouts.
- Clean the throttle body and do the relearn if needed.
- Inspect the connector and wiring.
- Replace the sensor or throttle body if the reading isn't smooth.
What does P0121 mean on your vehicle?
The likely cause depends on your engine. iRepair researches your exact year, make, model and engine (service bulletins, recalls and owner reports) and tells you what to check first. Your first 3 questions are free.
Ask iRepair about P0121No scanner? Most auto parts stores read check-engine codes for free.
Related codes
General guidance for P0121 on most vehicles. Some makers use the same code a little differently; confirm in the service information for your vehicle, put safety first, and see a professional when in doubt.