OBD CodesWhat it means
The throttle position sensor reports how far the throttle valve is open. Modern cars have two sensors, A and B, that check each other. If the computer cannot trust the signal, it limits engine power for safety.
Codes in this group
| Code | Meaning |
|---|---|
| P0120 | Throttle position sensor A circuit fault |
| P0121 | Throttle position sensor A reading out of range |
| P0122 | Throttle position sensor A signal too low |
| P0123 | Throttle position sensor A signal too high |
| P0124 | Throttle position sensor A signal cuts in and out |
| P0220 | Throttle position sensor B circuit fault |
| P0221 | Throttle position sensor B reading out of range |
| P0222 | Throttle position sensor B signal too low |
| P0223 | Throttle position sensor B signal too high |
| P0224 | Throttle position sensor B signal cuts in and out |
Bank 1 is the side of the engine that has cylinder 1. Sensor 1 is before the catalytic converter and sensor 2 is after it. More terms explained.
What you may notice
- Reduced power or "limp" mode
- Jerky or delayed response to the accelerator
- Unsteady idle
- Automatic gearbox shifting oddly
Common causes
Most likely first:
- A worn sensor or throttle body
- A dirty throttle body
- A loose or corroded connector
- Damaged wiring
What to check first
- Note whether the car loses power suddenly: if so, drive gently to a workshop
- Check the plug on the throttle body
- A workshop may clean the throttle body and run a relearn procedure
Have a mechanic confirm. A fault code tells you which system reported a problem, not which part has failed. The same code can have several causes, and they differ between car models. Use this page to understand the code, then have a qualified mechanic test the car before any part is replaced.
After the repair
Once the cause is fixed, the code can be cleared with a scan tool, or the warning light goes out by itself after several trips without the fault. Clearing a code without fixing the cause only hides it for a while. More about clearing codes.
Related codes
Mass air flow (MAF) sensor (P0100), Manifold pressure (MAP) and barometric sensor (P0105), Intake air temperature sensor (P0110), Engine coolant temperature sensor (P0115), Thermostat and engine warm-up (P0125), Accelerator pedal sensor and throttle agreement (P2120), Electronic throttle actuator (P2100), Oxygen sensor before the catalytic converter (sensor 1) (P0130). All codes.
Written in November 2026. These are generic OBD-II codes, the same on all makes. Causes and repair steps differ between models.