OBD codes / P0120
P0120
SeriousThrottle/Pedal Position Sensor A Circuit
Take P0120 a bit more seriously than most sensor codes — it can cause reduced-power mode and poor throttle response, which matters in traffic. It's usually drivable gently to a shop, but get it diagnosed promptly and avoid relying on the car if throttle response feels off.
What this code means
The throttle position sensor (TPS) tells the computer how far the throttle is open so it can set fuel and, on drive-by-wire cars, control the throttle itself. P0120 is a general fault in the 'A' TPS circuit. Common causes are a failed sensor, a wiring or connector fault, or — on modern electronic throttle bodies where the sensor is built in — a failing throttle body. Because the computer relies on this for throttle control, a fault can drop the car into a reduced-power 'limp' mode.
Symptoms you might notice
- Hesitation, surging, or poor throttle response
- Reduced-power or 'limp' mode
- Rough or unstable idle
- Stalling in some cases
- Check-engine light, sometimes with a warning light
What it costs to fix
Typical range: $50–$500 · about ~0.3–1.5 hrs of labor
| If the cause is… | Part | Labor |
|---|---|---|
| Throttle position sensor (standalone) | $20–$100 | ~0.3–0.8 hrs |
| Electronic throttle body (integrated TPS) | $150–$500 | ~0.5–1.5 hrs |
| Wiring / connector repair | $10–$120 | ~0.5–1.5 hrs |
Cheap on older cars with a bolt-on sensor; more on newer drive-by-wire cars where it means the throttle body. Wiring/connector repairs are inexpensive once located.
The price swings on which cause it turns out to be — so confirm the cause before paying. Diagnose P0120 for my exact vehicle →
Frequently asked
Can I drive with P0120?
Cautiously and not for long. It can cause hesitation or reduced-power mode, which is risky in traffic. Driving gently to a shop is usually fine, but don't ignore it if throttle response is unpredictable.
Will P0120 cause limp mode?
It can. Because the computer depends on the throttle signal, a fault often triggers a reduced-power 'limp' mode as a safety fallback — the car runs but acceleration is limited until it's fixed.
Is the TPS part of the throttle body?
On most modern drive-by-wire vehicles, yes — so the repair may mean the whole electronic throttle body. Older cars often have a separate, cheaper bolt-on sensor.
How much does it cost to fix P0120?
Cheap on older cars with a standalone sensor; more on newer ones where it means a throttle body. Wiring fixes are inexpensive. Diagnosis tells you which applies before you buy parts.
Seeing P0120 on your car? Get a diagnosis specific to your exact year, make and model.
Diagnose P0120 for my vehicleGeneric OBD-II reference. Manufacturer-specific behavior varies — confirm with a scan tool and, for safety-related codes, a professional inspection.