P0171 Code: System Too Lean (Bank 1)
CodePage.genericDisclaimer
Qu'est-ce que cela signifie ?
Code P0171 indicates the engine control module has detected that the fuel system on Bank 1 is running too lean — there is too much air or too little fuel in the air-fuel mixture. The long-term fuel trim has exceeded its adjustment range.
Diagnostic system: Fuel trim and air metering
On a Genesis G80, the P0171 code should be diagnosed as part of the fuel trim and air metering group. Related codes and live data from this same system can change the repair priority, so avoid replacing parts from the code name alone.
Most Common Causes for Genesis G80
- Fuite de vide dans le système d'admission
- Capteur MAF sale ou contaminé
- Pompe à carburant faible ou défaillante
- Filtre à carburant obstrué
- Régulateur de pression de carburant défectueux
- Injecteur de carburant obstrué ou défectueux
- Fuite du joint du collecteur d'admission
- Fuite d'échappement avant la sonde lambda
- Sonde lambda (O2) défectueuse
Symptômes à surveiller
- Le voyant moteur est allumé
- Ralenti irrégulier ou instable
- Hésitation ou trébuchement à l'accélération
- Accélération faible ou réponse lente
- Le moteur cale de façon inattendue
- Consommation de carburant accrue
- Ratés d'allumage ou sensation de secousses
- Difficulté à démarrer le moteur
CodePage.beforeReplacing
- Read short-term and long-term fuel trims at idle and cruise.
- Inspect intake boots, vacuum hoses, PCV plumbing, and MAF sensor contamination.
- Check fuel pressure if trims suggest a lean condition under load.
- Check for blown fuses, weak battery voltage, and damaged connectors before buying major parts.
Comment Diagnostiquer
CodePage.commonMistakes
Replacing oxygen sensors because they report lean/rich exhaust when the real cause is air, fuel pressure, or MAF data. Always confirm the fault with freeze-frame data, live data, visual inspection, and circuit checks before spending money on parts.
CodePage.faq
Can I drive with the P0171 code?
If the check engine light is solid, you can usually drive to a safe location or mechanic. If the light is flashing, pull over immediately to prevent catastrophic engine or catalytic converter damage.
Will the P0171 code clear itself?
Once the underlying problem is fixed, the engine computer will run its self-checks. If it passes over several drive cycles, the light will turn off automatically. You can also clear it immediately using an OBD2 scanner.
Will this code fail an emissions test?
Yes. If the Check Engine Light is on due to the P0171 code, your Genesis will automatically fail an OBD2 plug-in emissions or smog test.
What should I check first for P0171?
Read short-term and long-term fuel trims at idle and cruise. Inspect intake boots, vacuum hoses, PCV plumbing, and MAF sensor contamination. Check fuel pressure if trims suggest a lean condition under load.
Join the Discussion
Estimation de réparation
Vacuum leak repair, MAF cleaning, or PCV hose repair
Major component replacement after live data and circuit tests confirm failure
Comprend les pièces et la main-d'œuvre. Peut varier selon l'emplacement.
Vacuum leaks and cleaning are cheap; fuel pump, injector, or MAF replacement costs more and should be verified.
Difficulté de réparation (DIY)
Can usually be performed at home with basic hand tools.