Home › P0442

P0442 EVAP System Small Leak Detected

What it means

The EVAP system found a small leak (roughly 0.040 inch) in the fuel vapor system.

Severity: Low

Can I drive it? Safe to drive. Mainly an emissions concern.

Common causes (most likely first)

Gas cap not sealing
Cracked EVAP hose or fitting
Leaking purge or vent valve
Leaking charcoal canister or filler neck

Likely fixes

Replace gas cap (cheap first step)
Smoke-test to find the leak
Replace the leaking component

DIY parts cost

$15–$250

Approximate estimate

Shop repair cost

$100–$600

Approximate estimate, parts + labor

DIY difficulty

Easy to Moderate

Varies by vehicle

Cost ranges are rough, approximate U.S. estimates and vary widely by vehicle, region, and parts brand. Always confirm the diagnosis before buying parts.

Parts you may need

Gas capCheck price
EVAP purge valveCheck price
EVAP vent valveCheck price
EVAP hoseCheck price

Affiliate links are placeholders. Verify fitment for your year/make/model.