What usually causes it
- A worn throttle position sensor
- A dirty throttle body, the housing around the throttle flap
- A loose plug or damaged wiring
- A failing throttle motor
P0121Starts at: Get it checked this week
Throttle sensor reading does not fit
The throttle position sensor reports how far the throttle flap is open. Its reading does not match what the engine or the other sensors report.
What to watch for
- The car suddenly has little power and the engine will not speed up
- Stalling or a rough idle
- The gas pedal feels dead, or the car surges
Can I keep driving?
We rate P0121 as Get it checked this week. It is not an emergency yet, but it can get worse. If the light starts flashing, stop driving soon.
Quick answers about P0121
What does P0121 mean?
Throttle sensor reading does not fit. The throttle position sensor reports how far the throttle flap is open. Its reading does not match what the engine or the other sensors report.
Can I keep driving with P0121?
We rate P0121 as Get it checked this week. It is not an emergency yet, but it can get worse. If the light starts flashing, stop driving soon.
What usually causes P0121?
The most common causes, in order: A worn throttle position sensor; A dirty throttle body, the housing around the throttle flap; A loose plug or damaged wiring; A failing throttle motor.
Estimates only. A mechanic should confirm. The same code can mean slightly different things on different cars; the app explains it for your exact year, make, model and mileage.