P0171 or P0174 readings indicate too lean of a system in one of your cylinder banks. Learn common causes and solutions to these trouble codes.

The P0171 code (System Too Lean Bank 1) basically means your engine’s getting too much air and not enough fuel. The usual suspects? Vacuum leaks, dirty MAF sensors, or fuel delivery …

May 25, 2022 · “Code P0171 – system too lean bank 1” means there is too much oxygen or too little fuel in the exhaust, which is referred to as a “lean” condition, or a lean or “low fuel trim” code.

Aug 19, 2024 · The P0171 diagnostic trouble code indicates that the fuel system is running lean on bank 1 of the engine. This means that there is an imbalance in the air-fuel mixture being …

Jan 10, 2025 · With less fuel delivered than required, the engine runs on a lean air-fuel mixture, which commonly triggers code P0171. Fix: Try using a fuel injector cleaner as a first step.

Apr 11, 2025 · Code P0171, officially designated as “System Too Lean (Bank 1)” by the Society of Automotive Engineers, signals that your engine’s air-fuel mixture contains too much air and …