P0123 Code: Throttle Position Sensor/Switch Circuit High Input
🟠 Moderate severity · drivable
Drivable, but the throttle reading is too high, which can cause surging and poor idle.
What P0123 means
The throttle position sensor (TPS) is reporting voltage that's too high for the throttle's actual position. The computer may think the throttle is open when it isn't.
Symptoms
- Check engine light is on
- Surging or high idle
- Hesitation on acceleration
- Poor fuel economy
Common causes
- most common: Faulty throttle position sensor
- common: Open or damaged TPS wiring
- less common: Corroded TPS connector
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Replace the throttle position sensor | Yes | $50–150 |
| Repair open TPS wiring | Mechanic | $50–150 |
Frequently asked questions
Can I drive with a P0123 code?
Yes, but you may notice surging and high idle. Fix it soon.
What is the most common cause of P0123?
A faulty throttle position sensor reading high voltage.
How much does it cost to fix a P0123?
Typically $50–$150 for a new throttle position sensor.
Related codes
P0121
P0121 Code: Throttle Position Sensor/Switch Circuit Range/Performance
P0122P0122 Code: Throttle Position Sensor/Switch Circuit Low Input
P0120P0120 Code: Throttle Position Sensor Circuit
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.