P0171: System Too Lean (Bank 1)
What this check-engine code means in plain English, what usually causes it, and what a fix typically costs.
What P0171 means
The engine control module has detected that the air-fuel mixture on Bank 1 (the side of the engine containing cylinder #1) is too lean, meaning there's too much air or not enough fuel. The computer has tried to compensate by adding more fuel, but the mixture is still outside the acceptable range.
What causes P0171?
Is P0171 safe to drive?
You can typically drive short distances with this code, but prolonged operation with a lean condition can cause engine damage from overheating or detonation. Address it within a few days to prevent potential catalytic converter damage or internal engine wear.
P0171 repair cost
Industry-average estimates. Cost depends heavily on the root cause, ranging from a simple vacuum hose replacement to fuel pump or injector service.
Which one is it for your car?
Plug a cheap OBD2 adapter into your car and CarSense reads your codes and tells you the likely cause and a real cost for your exact vehicle — free to scan, no proprietary dongle.