GM Vehicle Error Code P1171: How to Fix It

Q: What causes GM P1171 error code?

P1171 is typically caused by vacuum leaks, faulty mass airflow sensor, weak fuel pump, clogged fuel injectors, or failing oxygen sensors. The most common cause is unmetered air entering the intake system through vacuum leaks.

Q: Can I drive with P1171 code?

You can drive short distances with P1171, but avoid hard acceleration and high speeds. The lean condition can cause engine damage over time, including burned valves or pistons. Get it diagnosed and repaired promptly.

Q: How much does it cost to fix P1171?

Repair costs vary widely depending on the root cause. Simple vacuum hose replacement costs $20-50, while fuel pump replacement can cost $400-800. Mass airflow sensor replacement typically costs $150-300 including labor.

Q: Will P1171 cause my car to fail emissions testing?

Yes, P1171 will likely cause emissions test failure because it indicates the fuel system is not operating within proper parameters. The code must be resolved and the system must complete readiness monitors before passing emissions.

Q: What's the difference between P0171 and P1171?

P0171 is a generic lean condition code affecting bank 1, while P1171 is GM-specific and indicates lean condition specifically during acceleration. P1171 provides more specific diagnostic information for GM vehicles.

Abstract

GM error code P1171 indicates your vehicle's fuel system is running lean during acceleration, meaning there's too much air or not enough fuel in the air-fuel mixture. This can cause poor acceleration, rough idling, and reduced fuel economy.