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P0456 EVAP System Very Small Leak Detected

What it means

The EVAP system detected a very small leak (around 0.020 inch). These can be hard to find.

Severity: Low

Can I drive it? Safe to drive.

Common causes (most likely first)

Gas cap seal
Purge or vent valve leaking slightly
Tiny crack in hose or filler neck

Likely fixes

Replace gas cap
Smoke-test the system
Replace leaking valve or hose

DIY parts cost

$15–$250

Approximate estimate

Shop repair cost

$100–$600

Approximate estimate, parts + labor

DIY difficulty

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

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