OBD-II FAULT CODE
P0121
Throttle Position Sensor/Switch A Circuit Range/Performance Problem
Meaning, symptoms, likely causes, diagnostic checks and repair guidance for P0121.
- Check Engine light
- Poor drivability or reduced fuel economy depending on fault
- Reduced power / limp mode possible
- Hesitation or unstable idle
- Dirty throttle body
- Faulty throttle/pedal position sensor
- Wiring/connector fault
- Adaptation needed
- Signal out of expected range
- Scan all modules and record freeze-frame data before clearing codes
- Check battery voltage and related fuses
- Inspect throttle body and connector
- Check sensor correlation data with scan tool
- Compare live data to expected value and inspect mechanical operation
- Clean throttle body if appropriate, repair wiring, perform throttle relearn, replace failed sensor/body after testing
- Repair mechanical cause, clean/replace sticking actuator, or replace sensor after confirmation
Related Codes
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Disclaimer: Information is provided for general guidance only and may not apply to all vehicles. Always consult a qualified technician.