P0171System Too Lean (Bank 1)
The computer detects too much air and too little fuel in the bank 1 mixture.
Can I keep driving? With caution
You can drive to the shop, but do not postpone the repair. The problem may worsen and damage other components.
Sistema Afectado
Aire / Combustible · Inyección, MAF, MAP, O₂
Relacionado con la mezcla aire-combustible: sensores de flujo, presión, inyectores o bomba.
Espacio para vendedores de repuestos
Aún no hay un anunciante en este espacio.
Symptoms You Will Notice
What you may observe when this code appears
- Rough idle
- Hesitation on acceleration
- Backfiring through the exhaust
- Power loss on hills
Possible Causes
The components or conditions that trigger this code
- 1Intake vacuum leak
- 2Dirty MAF sensor
- 3Weak fuel pump
- 4Clogged injectors
- 5Blocked fuel filter
How to Fix It — Step by Step
Recommended diagnostic and repair procedure
- 1Check for vacuum leaks with spray
- 2Clean or replace the MAF sensor
- 3Check the fuel pressure
- 4Clean the injectors
Note: This information is for general reference. For precise diagnostics and safety repairs, always consult a certified mechanic.
Estimated Cost
Approximate range in USD (varies by region and shop)
Sensors + injectors
* Diagnosis only: $50–$150
Quick Info
Dig Deeper
Videos, images and service manuals
Have Another Code?
Look it up directly: