P0440

Evaporative Emission System Malfunction

Low — drive on, check soonPowertrain (engine & transmission)

System

Powertrain (engine & transmission)

Type

Generic (standardized)

Subsystem

Auxiliary emission controls

What it means

A general fault in the evaporative-emissions system, which captures fuel vapours from the tank.

Check-engine light; sometimes a fuel smell. No drivability effect.

Loose or faulty fuel cap, cracked EVAP hose, or a faulty purge/vent valve.

Check the fuel cap first (tighten or replace), then inspect EVAP hoses and valves.

What does code P0440 mean?

Evaporative Emission System Malfunction. A general fault in the evaporative-emissions system, which captures fuel vapours from the tank.

What are the symptoms of P0440?

Check-engine light; sometimes a fuel smell. No drivability effect.

What causes P0440?

Loose or faulty fuel cap, cracked EVAP hose, or a faulty purge/vent valve.

What should I do about P0440?

Check the fuel cap first (tighten or replace), then inspect EVAP hoses and valves.

General reference based on the SAE J2012 standard. Exact causes for your vehicle may differ — when in doubt, consult a workshop.