OBD-II FAULT CODE
P0440
Evaporative Emission Control System Malfunction
Meaning, symptoms, likely causes, diagnostic checks and repair guidance for P0440.
- Check Engine light
- Poor drivability or reduced fuel economy depending on fault
- Fuel smell possible
- Usually little drivability change
- Loose/damaged fuel cap
- Cracked EVAP hose
- Faulty purge/vent valve
- Leaking canister
- Scan all modules and record freeze-frame data before clearing codes
- Check battery voltage and related fuses
- Check fuel cap seal first
- Smoke-test EVAP system
- Command purge/vent valves with scan tool if available
- Replace damaged cap/hoses, repair leaks, replace stuck purge or vent valve after testing
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Disclaimer: Information is provided for general guidance only and may not apply to all vehicles. Always consult a qualified technician.