Dec 31, 2025 · Learn what's causing your engine to run too lean and triggering the P0171 code, and how to fix it before it leads to costly repairs.

Dec 7, 2025 · P0171 System Too Lean explained. Learn symptoms, causes, repair costs, and proven fixes. Diagnose vacuum leaks, MAF issues, and fuel trim problems easily.

Mar 17, 2023 · What does the P0171 code mean? The P0171 code indicates that the oxygen (O2) sensor on bank 1 sent a signal to the engine control module that the air-fuel mixture is too lean to be …

Aug 19, 2024 · The P0171 code means that more air than gasoline is detected in the exhaust gases exiting the combustion chamber. If the P0171 is set in along with the P0174 code, it is highly likely …

Details on causes of DTC P0171 and troubleshooting steps. Common fixes include cleaning the MAF sensor and repairing for vacuum leaks.

Jan 24, 2026 · P0171 code gets triggered when the Engine Control Module receives an input signal from the oxygen sensor —also called the air-fuel ratio sensor —indicating that the air/fuel mixture has …

A P0171 code, “System Too Lean (Bank 1),” means your engine is running with too much air or too little fuel, triggering the check engine light and risking damage if ignored. This guide covers the P0171 …

When your powertrain/engine control module receives a reading that indicates there’s too much oxygen and the ratio is incorrect, it sends an error code P0171 or P0174. Depending on the problem, it may …

Jan 6, 2018 · When I see a P0171 code (Bank 1 lean) and/or a P0174 code (Bank 2 lean), I start by looking for a vacuum or exhaust leak. Or, why isn’t the engine getting enough fuel? Because that’s …

Dec 15, 2025 · Understanding this code is the first step toward diagnosing and resolving the underlying engine imbalance. The P0171 code translates to “System Too Lean, Bank 1,” which describes a …