Start your diagnosis by cleaning the maf sensor, a quick and inexpensive step.
Common causes of code p0171 in a subaru include a vacuum leak, faulty oxygen sensor, dirty or clogged fuel injectors, a malfunctioning mass airflow.
Your subaru’s check engine light just came on, and the code reader says p0171
Don’t panic—but don’t ignore it either
This “system too lean” code means your engine’s getting too much.
The most common causes of p0171 are a bad oxygen.
Hey all, i own a 2004 impreza wrx sti and i'm getting error code p0171 fuel trim malfunction (it's running lean.) i've so far replaced maf sensor, pcv valve, cai filter.
Just looking to for some peace of mind, this morning as i was leaving my house most of my lights on my dash came on, at this time it was 19 degrees outside which i thought was the issue, i went.
P0171 means your engine is running lean on bank 1 — the most common fix is cleaning the maf sensor ($8, 10 minutes)
This code sets when the pcm (engine computer) has added as much extra fuel as it.
Check for air leaks in the intake system
90% of the time this is the problem
This is where the service manual will start you out
Common leaks are turbo inlet, throttle body coupler, intercooler.
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.