Subaru Error Code P0171: How to Fix It

Q: Can I drive my Subaru with P0171 error code?

You can drive short distances, but avoid extended driving or high performance demands. The lean condition can cause engine damage over time, including overheating and internal component wear. Get it diagnosed and repaired as soon as possible.

Q: What's the most common cause of P0171 in Subaru vehicles?

The most common causes are a dirty or faulty MAF sensor, vacuum leaks in the intake system, and clogged air filters. Subarus are particularly sensitive to MAF sensor contamination from aftermarket air filters or oil vapors.

Q: How much does it cost to fix Subaru P0171?

Costs vary widely depending on the root cause. Simple fixes like cleaning the MAF sensor or replacing vacuum hoses cost $20-50. Replacing the MAF sensor runs $200-400, while fuel system repairs can range from $300-800 depending on the components needed.

Q: Will P0171 cause my Subaru to fail emissions testing?

Yes, P0171 will typically cause your vehicle to fail emissions testing since it indicates the engine is not running at optimal air-fuel ratios. The error code must be resolved and the system must complete its readiness monitors before passing emissions.

Abstract

Error code P0171 in your Subaru indicates the engine is running too lean on Bank 1, meaning there's too much air and not enough fuel in the air-fuel mixture. This commonly occurs due to a faulty Mass Air Flow (MAF) sensor, vacuum leaks, or fuel system issues that need immediate attention to prevent engine damage.