P0440 Fault Code

Long Description

Fault P0440 is logged when the vehicle’s primary computer, the powertrain control module (PCM), has detected a malfunction with the evaporative emission control (EVAP) system.

This happens simply when there are any issues with the system. This means it will likely come with another more specific fault code if the PCM can determine it.

It is possible that the system has detected a significant leak.

The EVAP system is a closed system found in a vehicle to prevent fuel fumes from being emitted into the surrounding atmosphere. These systems became a mandatory requirement for modern vehicles, meaning almost every car on the road today will have this system.

General Motors and Chrysler brands like Cadillac, Dodge, and Jeep are some of the most commonly searched when it comes to this fault code.

Other Signs of This Problem

It can be notoriously difficult to diagnose an issue with the EVAP system as there can be very few additional signs of an issue.

The easiest way to identify this is the presence of the Check Engine light on the dashboard. Additionally, there may be other EVAP system fault codes like P0441 through to P0455.

These codes can be very useful in pinpointing where the malfunction in the system is coming from.

In very rare cases, there may be a smell of fuel from your vehicle. This can be picked up easier in confined spaces like a garage. This also depends on the size of the leak, if there even is one.

What Could Be The Problem?

All of the potential causes for an EVAP malfunction are found within the system itself. This is because it operates independently from all other systems, apart from being connected to the PCM.

One of the most common issues for any EVAP fault code is a loose or damaged gas cap. This can allow emissions to leak from the system, triggering any number of codes.

This is also true of a gas cap that is not factory-fit for the vehicle in question.

An actual leak is obviously one of the main causes of this P0440 fault code.

All the other components in the EVAP system can be in question. The charcoal canister, purge volume valve, canister vent control valve, and EVAP hose are all able to cause this code if they are defective.

Fixes

Most of the fixes for the EVAP system involve replacing faulty parts or repairing leaks in the system.

The first step in fixing any issue should be checking the gas cap. It should be checked for seal damage and tightened properly. The fault code should be reset and tested after this.

If the code persists, it is a good idea to check for leaks in the various components. This can be done using a specialist diagnostic tool called a “smoke machine.”

Any faulty parts should be replaced.

Seriousness

Fault code P0440 can be considered low in seriousness. There are no real risks to the occupants of the vehicle or the vehicle itself with an EVAP malfunction.

However, if for whatever reason your car is subjected to an emissions test, it will very likely fail. This can result in significant fines depending on the region you are in.

It is a good idea to have this issue fixed within a few weeks.