P0122 Code: Throttle Position Sensor Low — Causes & Fix
P0122 means the throttle position sensor (TPS) signal is too low — the ECM cannot read how far the throttle is open.
- 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
Typical causes are a short to ground in the TPS wiring, a failed sensor, or a connector fault. P0122 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
- Poor throttle response or hesitation
- Stalling or limp mode
How to fix it
- 1
Inspect the TPS connector and wiring
1. Locate the TPS on the throttle body. 2. Reseat the connector and check for a shorted signal wire.
- 2
Test the sensor sweep
1. Backprobe the signal and open the throttle — voltage should rise smoothly. 2. Replace the sensor/throttle body if faulty, then clear the code.
Frequently asked questions
Why is my car in limp mode with P0122?
Without a valid throttle signal the ECM limits power for safety. Fix the TPS circuit to restore normal response.
Last updated July 19, 2026
Guidance only — always consult a qualified professional or the official service manual before carrying out repairs.