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P0440 Evaporative Emission (EVAP) System Malfunction

What it means

The EVAP system, which traps fuel vapors from the tank, has a general fault or leak.

Severity: Low

Can I drive it? Safe to drive. It affects emissions and may cause a fuel smell, but not engine health.

Common causes (most likely first)

Loose, damaged, or wrong gas cap
Faulty purge or vent valve
Cracked EVAP hose
Damaged charcoal canister

Likely fixes

Tighten or replace the gas cap and clear the code
Smoke-test EVAP system
Replace faulty valve/hose/canister

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.