Throttle/Pedal Position Sensor A Circuit Low Input
Diagnose P0122 throttle position sensor code. Learn why the TPS reads low and how to test and replace it.
What you may notice
Symptoms
- 01Check engine light on
- 02Hesitation or stumbling on acceleration
- 03Surging or erratic idle
- 04Reduced power or limp mode
- 05Harsh or delayed shifting
Where to look first
Common causes
- 01Faulty throttle position sensor
- 02Damaged or shorted wiring
- 03Poor connector contact or corrosion
- 04Worn throttle body
- 05Bad ground or reference voltage
Step by step
What to check and repair
- 01Inspect TPS wiring and connector
- 02Check reference voltage and ground
- 03Test the TPS signal through its range
- 04Clean or replace the throttle body if worn
- 05Replace the TPS or throttle body if faulty
What Does P0122 Mean?
The P0122 code indicates that the Throttle Position Sensor (TPS) circuit is sending a voltage signal that is lower than the expected range. The TPS tells the ECM how far the throttle is open.
Why TPS Data Matters
The ECM uses throttle position to control fuel delivery, ignition timing, and shifting. A low or erratic signal can cause hesitation, surging, and shifting problems.
Common Causes
A faulty TPS, worn throttle body, or wiring problems are typical. On electronic throttle systems, this may involve the accelerator pedal sensor as well.
How AI4Car Helps
AI4Car can display live throttle position as a percentage, helping you confirm whether the signal tracks smoothly as the throttle opens and closes.