P0442 on a Subaru: Causes, Fixes & Repair Cost

🟢 Low severity · drivable

You can keep driving — this is an emissions leak, not an engine problem — but fix it before your next emissions test.

What P0442 means on a Subaru

On a Subaru, P0442 means the engine computer detected a small leak in the evaporative emission (EVAP) system that captures fuel vapors from the tank. Subaru checks the fuel system for pressure loss, so a small leak in a hose, valve, or seal sets the code. The car keeps running and driving normally.

Is P0442 common on Subarus?

P0442 appears regularly on Subarus, most often starting with a loose gas cap and then, as the car ages, cracked hoses around the purge solenoid or a worn purge valve. The rubber lines under the hood and near the fuel tank dry out over time. It is an emissions concern, not a mechanical failure.

Commonly reported on: Outback, Forester, Impreza, Crosstrek.

Symptoms

Check engine light on
Possible faint fuel smell
No change in how the car drives

Common causes

most common: Loose, missing, or failing gas cap
common: Cracked EVAP hoses near the purge solenoid
common: Faulty purge valve
less common: Leaking fuel filler hose

How to fix it

Fix	DIY?	Typical cost
Tighten or replace the gas cap	Yes	$10–30
Replace cracked EVAP hoses	Yes	$20–80
Smoke test the EVAP system to locate the leak	Mechanic	$50–150
Replace the purge valve	Yes	$50–140