OBD codes / P0123
P0123
SeriousThrottle/Pedal Position Sensor A Circuit High
Treat P0123 with some care — like P0122 it can cause reduced-power mode and poor throttle response, which matters in traffic. Usually drivable to a shop, but get it diagnosed promptly and don't rely on the car if acceleration feels unpredictable.
What this code means
P0123 is the mirror of P0122: the throttle position sensor (TPS) is reading too HIGH (as if the throttle were wide open) or its circuit is shorted to voltage. The TPS tells the computer the throttle angle for fueling and, on drive-by-wire cars, throttle control. Common causes are a failed sensor, a wire shorted to power, or a corroded connector. On modern electronic throttle bodies the sensor is integrated, so the fix may be the whole unit. A faulty throttle signal can trigger reduced-power "limp" mode for safety.
Symptoms you might notice
- Hesitation, surging, or erratic throttle response
- Reduced-power or "limp" mode
- High or unstable idle
- Harsh or unexpected automatic shifts
- 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 |
Same as P0122: 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 P0123 for my exact vehicle →
Frequently asked
Can I drive with P0123?
Cautiously and briefly. It can cause erratic throttle response or reduced-power mode, which is risky in traffic. Driving gently to a shop is usually okay, but don't put off the repair.
What's the difference between P0122 and P0123?
They're the same sensor failing in opposite directions: P0122 reads too low (or shorted to ground), P0123 reads too high (or shorted to voltage). Diagnosis and repair are essentially the same.
Will P0123 cause limp mode?
It can. A throttle signal the computer can't trust often triggers a reduced-power fallback so the car stays controllable until the sensor or throttle body is fixed.
How much does it cost to fix P0123?
Inexpensive on cars with a standalone sensor; more on newer ones where it means a throttle body. A wiring or connector repair is cheap. Diagnosis determines which before buying parts.
Seeing P0123 on your car? Get a diagnosis specific to your exact year, make and model.
Diagnose P0123 for my vehicleGeneric OBD-II reference. Manufacturer-specific behavior varies — confirm with a scan tool and, for safety-related codes, a professional inspection.