Subaru Error Code P1421: How to Fix It

Q: Can I drive with Subaru error code P1421?

Yes, you can continue driving with P1421 as it's not a critical safety issue. However, you may experience slightly reduced fuel economy and the vehicle may fail emissions testing. It's best to address the issue within a few weeks.

Q: What causes Subaru P1421 error code?

P1421 is commonly caused by a loose or damaged fuel cap, cracked vacuum hoses in the EVAP system, a faulty fuel tank pressure sensor, or a malfunctioning charcoal canister purge valve. Environmental factors like temperature changes can also trigger this code.

Q: How much does it cost to fix P1421 on a Subaru?

Repair costs vary widely depending on the root cause. A new fuel cap costs $15-30, vacuum hoses cost $10-50, while a fuel tank pressure sensor replacement can cost $150-400 including labor. Professional diagnosis typically costs $100-150.

Q: Will P1421 clear itself on a Subaru?

P1421 may clear itself if the issue was temporary (like a loose fuel cap that's now properly tightened), but it typically requires manual clearing with an OBD2 scanner. The code will return if the underlying problem isn't fixed.

Q: Does P1421 affect Subaru performance?

P1421 generally doesn't affect engine performance or power output. You may notice slightly reduced fuel economy and the check engine light will remain on, but normal driving characteristics should be unaffected.

Abstract

Subaru error code P1421 indicates a problem with the fuel tank pressure control system, specifically related to the evaporative emission control system. This code typically appears when the fuel tank pressure sensor or related components aren't functioning properly, which can affect fuel efficiency and emissions but won't leave you stranded.