Subaru Error Code P0174: How to Fix It

Q: Can I drive my Subaru with P0174 error code?

You can drive short distances, but avoid extended driving as lean conditions can damage the engine. Address the issue promptly to prevent costly repairs to pistons, valves, or catalytic converter.

Q: What's the difference between P0171 and P0174 codes?

P0171 indicates Bank 1 is running lean, while P0174 indicates Bank 2 is running lean. Bank 2 is the side of the engine that doesn't contain cylinder #1. Both codes have similar causes and diagnostic procedures.

Q: How much does it cost to fix Subaru P0174?

Costs range from $20 for an air filter replacement to $500+ for fuel pump replacement. Most common fixes like vacuum leaks or MAF sensor cleaning cost $50-200 in parts and labor.

Q: Will P0174 cause my Subaru to fail emissions testing?

Yes, P0174 will typically cause your vehicle to fail emissions testing. The code must be cleared and the issue resolved before passing inspection.

Q: Can a bad gas tank cap cause P0174?

While a loose gas cap typically triggers evaporative emission codes (P0440 series), a severely damaged cap could potentially contribute to lean conditions, though this is uncommon for P0174 specifically.

Abstract

Subaru error code P0174 indicates that Bank 2 of your engine is running too lean, meaning there's too much air and not enough fuel in the air/fuel mixture. This can cause rough idling, poor fuel economy, and potential engine damage if left unaddressed.