P0120 — Throttle/Pedal Position Sensor "A" Circuit
Drive with caution — fix soon.
What P0120 means
P0120 points to a problem in the throttle or accelerator pedal position sensor 'A' circuit. This sensor tells the computer how far the throttle or pedal is pressed. Faults often come from a worn sensor, wiring problems, or a dirty throttle body, and can cause poor or erratic acceleration.
Common symptoms
- Check engine light is on
- Erratic or hesitant acceleration
- Engine entering reduced-power (limp) mode
- Rough or unstable idle
- Unexpected surging or stalling
Common causes
- Faulty throttle position sensor
- Worn or dirty throttle body
- Damaged or shorted sensor wiring
- Corroded or loose connector
- Accelerator pedal position sensor fault
Typical repair cost
$100 – $500
Varies by vehicle and root cause.
Frequently asked questions
Can I drive with a P0120 code?
You can sometimes, but acceleration may be erratic or limited by limp mode. If the car feels unsafe or unpredictable, avoid driving until it's checked.
How much does a P0120 repair cost?
Usually $100 to $500. A sensor or cleaning is on the lower end, while a full throttle body replacement costs more.
Is P0120 dangerous?
It's moderate. The main risk is unpredictable acceleration or sudden power loss, which is why it's wise to fix it promptly.
What is limp mode and why does it happen?
Limp mode is a protective state where the computer limits power to keep you safe when it can't trust the throttle signal.