Parts
$0–150
P0440 — EVAP System Malfunction (general)
SAFEIs it safe to drive? An emissions/fuel-vapor fault. No drivability danger — fix it on your schedule (it will fail an emissions test).
What P0440 means
The evaporative emissions system — which traps fuel vapors and routes them back to be burned — has a general fault, often a leak or a valve.
Most likely causes (in order)
- Loose, cracked, or missing gas cap (check first, free)
- Cracked EVAP hose
- Faulty purge or vent valve
- Charcoal canister fault
Symptoms you might notice
- Check-engine light (usually no symptom)
- Occasional fuel smell
What to check first
Tighten or replace the gas cap and clear it. If it returns, smoke-test the EVAP system to find the leak.
Repair cost & difficulty
Labor
0.2–1.5 hr
Difficulty
Easy DIY