OBD code P0440

The evaporative emissions system has a general fault, often related to leaks, the purge valve or associated components.

Estimated severity

Low

Common symptoms

Check engine light on
Usually no noticeable change in how the vehicle drives
Fuel smell near the vehicle in some cases

Likely causes

Fuel cap not sealing correctly or damaged seal
Cracked or disconnected EVAP hoses
Faulty EVAP purge valve
Leaks in the charcoal canister

Recommended checks

1. Start by checking the fuel cap, including correct tightening and seal condition.
2. Visually inspect EVAP hoses and connections.
3. Test the EVAP purge valve electrically and mechanically.
4. In a workshop, use a smoke machine to locate small leaks.

What does code P0440 mean?

Code P0440 indicates a general fault in the EVAP system, which prevents fuel vapors from escaping into the atmosphere. It usually does not affect how the engine drives, but it does affect emissions and may cause an inspection failure.

Try assisted diagnostics