P0440: Evaporative Emission Control System Malfunction

What Does The P0440 Code Mean?

This indicates that a part of the EVAP control system is no longer fuctioning correctly. The EVAP system consists of many parts, including (but not limited to) the gas cap, fuel lines, carbon canister, purge valve, and other hoses

The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle’s fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine.

What Are The Symptoms Of The P0440 Code?

You likely won’t notice any drivability problems.

What Are The Potential Causes Of The P0440 Code?

A code P0440 could mean one or more of the following has happened:

• The gas cap is not installed or working properly
• The purge solenoid has failed
• The canister is plugged and not working properly

How Can You Fix The P0440 Code?

With a P0440 OBD-II trouble code, diagnosis can be tricky at times. Here are some things to try:

• Remove and reinstall the gas cap, clear the code, and drive for a day and see if the codes come back.
• Inspect the EVAP system for cuts/holes in tubes/hoses
• Inspect for damaged or disconnected hoses around the Evap purge solenoid
• Check and/or replace the sensor
• Check and/or replace the purge valve
• Have a professional use a smoke machine to detect leaks

Recommended Parts

Below are some recommended auto parts to help you address the trouble code affecting your vehicle and get it running smoothly again:

>>> Canister Purge Valve - Mopar (4892890AA)
>>> Purge Solenoid Valve
>>> Autel Scanner MaxiCOM MK808S

Note: During the purchasing process, please check carefully whether the part you want to buy fits your car!

Check This Video For Reference

P0440 Infographic - 1 Minute Summary

Reference Sources

Diagnostic Chart with Trouble Code for LHD Vehicles for P0440 – Pages 114-117.