Trouble codes › P0120
P0120 Throttle/Pedal Position Sensor/Switch "A" Circuit
Throttle
P0120 means the engine computer isn't getting a usable signal from throttle position sensor A, which often triggers reduced power.
The engine computer isn't getting a usable signal from throttle position sensor A, which tells it how far the throttle is open.
The engine may hesitate, surge or go into reduced power without warning, which can be dangerous in traffic. Get it fixed before relying on the vehicle.
Common causes
- A failed throttle position sensor (often inside the electronic throttle body)
- An unplugged or corroded connector
- Damaged wiring or a 5-volt reference problem
Symptoms
- Reduced power or limp mode
- Hesitation, surging or erratic idle
- Check-engine light
What to check first
- Inspect the throttle body's connector and wiring.
- Check the 5-volt reference and ground.
- Watch the throttle position reading with a scan tool while slowly pressing the pedal: it should rise smoothly without jumps.
- Replace the sensor or throttle body if the signal is erratic.
What does P0120 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 P0120No scanner? Most auto parts stores read check-engine codes for free.
Related codes
General guidance for P0120 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.