P0123 Code: Throttle Position Sensor High — Causes & Fix
P0123 means the throttle position sensor (TPS) signal is too high — an implausible wide-open reading.
- Applies to
- All OBD-II vehicles (any make or model)
- Est. repair cost
- $30 – $400
- Time to fix
- 30 minutes – 2 hours
What it means
Common causes are a short to voltage in the TPS wiring, a failed sensor, or a connector fault. P0123 is a generic OBD-II powertrain code defined in the SAE J2012 standard, so it applies to virtually any 1996-or-newer petrol car or light truck regardless of make. Fix the underlying fault, then clear the code with an OBD-II scan tool — it will return if the problem isn't resolved.
Symptoms
- Check engine light on
- Surging or erratic idle
- Hesitation or limp mode
How to fix it
- 1
Check wiring and connector
1. Inspect the TPS signal wire for a short to power. 2. Reseat the connector.
- 2
Replace the sensor if needed
1. Confirm the signal is stuck high. 2. Replace the TPS/throttle body, then clear the code.
Frequently asked questions
Is P0123 the same as P0122?
They are opposites — P0122 is a low (near-zero) throttle signal, P0123 is a high (near-max) signal. Both usually point to the sensor or its wiring.
Last updated July 19, 2026
Guidance only — always consult a qualified professional or the official service manual before carrying out repairs.