P0171
GENERIC DTC · Fuel & air
System too lean — bank 1
Ce que le code signifie
Closed-loop fuel correction reached a calibrated lean threshold on bank 1.
Gravité et conduite
Service soon; urgent with misfire or power loss
Causes possibles
- Unmetered intake air
- Low fuel delivery
- Exhaust leak near sensor
- Biased airflow or oxygen-sensor signal
Prochaines vérifications
- Record short- and long-term fuel trim at idle and raised RPM
- Inspect only visible intake hoses with engine off
- Check related misfire or airflow codes
Source et limite
Code structure follows SAE J2012. Manufacturer-specific definitions, pinpoint tests, wiring, torque, fluids, and repair procedures require authoritative information for the exact vehicle.
SAE J2012 Diagnostic Trouble Code DefinitionsReviewed 2026-08-13