P0120 Code: Throttle Position Sensor Circuit
🟠 Moderate severity · drivable
The car usually still drives, but it may feel sluggish or limit speed in limp mode.
What P0120 means
The throttle position sensor (TPS) tells the computer how far the gas pedal is pressed. This code means the sensor circuit is not working. The computer may put the engine in a reduced power or limp mode.
Symptoms
- Check engine light on
- Reduced power or limp mode
- Poor acceleration
- Rough idle
- Engine does not respond smoothly to the pedal
Common causes
- most common: Faulty throttle position sensor
- common: Damaged wiring or connector
- less common: Carbon buildup on the throttle body
- less common: Faulty pedal position sensor on drive-by-wire cars
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Replace the throttle position sensor | Yes | $40–150 |
| Repair the wiring or connector | Yes | $20–80 |
| Clean the throttle body | Yes | $10–40 |
| Replace the pedal position sensor | Mechanic | $100–300 |
Frequently asked questions
Can I drive with P0120?
Yes, but the engine may go into limp mode with reduced power. Drive gently and get it checked soon.
What is limp mode?
It is a safe mode where the computer limits engine power to protect the engine while a sensor problem exists.
Will cleaning the throttle body fix P0120?
Sometimes. Carbon can make the sensor read poorly, but a failed sensor or wiring problem needs parts.
Related codes
P0121
P0121 Code: Throttle Position Sensor/Switch Circuit Range/Performance
P0122P0122 Code: Throttle Position Sensor/Switch Circuit Low Input
P0123P0123 Code: Throttle Position Sensor/Switch Circuit High Input
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.