Ford Focus P0456: EVAP System – Small Leak

The most frequent trouble code with the Ford Focus Is the P0456 Code. This is the trouble code that you get when you plug in your Focus to an a OBDII scanner. The code P0456 indicates that the evaporative emissions control system has a tiny leak. It is sometimes found along with other codes such as P0440, P0441, or very frequently P0440.

The P0456 issue is not usually a threat to your Focus' driveability. Certainly anytime the service engine soon light is on, it’s good to deal with it as soon as possible.

While the trouble code may state that there is a “small leak” in the EVAP system of your Ford Focus, it is actually referring to the amount of pressure lost, and not the physical size of the leak. This can happen in very small amounts.

Ford Focus P0456 Definition

P0456 stands for a universal OBDII Trouble Code. It means that no matter what make or model vehicle you have, this code will still mean the same thing. Technically the code is:

System Leakage in the Smallest Detail – Evaporative Emission System

The EVAP captures any fuel vapor in the tank, and transmits it to engines intake for ignition. When there is a small leak in the Ford Focus’s EVAP system, it will throw the P0456 OBDII Code. If there is a large leak, it’ll throw P0455.

Ford Focus OBDII Code Symptoms P0456

A P0456 Code will not usually be associated with other noticeable symptoms. The smell of gas And the service engine soon light.

The fuel tank and fuel filler tubes should smell particularly strong.

The EVAP system is responsible for fuel vapors. If these vapors are leaking from the system, you’ll often smell them faintly while operating the vehicle. But, it won’t affect the way the engine itself runs. The EVAP system is for fuel vapor and does not affect the operation of your Focus' engine.

Focus P0456 Trouble code Causes

P0456 can be triggered by many factors in your Ford Focus. If your Focus has warned you at all in the last few months that the fuel cap was off when it wasn’t, then replacing it would be a great first step.

These are some of the most frequent problems that can throw off the code. They're listed in alphabetical order, from the most likely to the least.

• Hose for Evap System– The hose that carries the fuel vapor from the fuel tank to the intake manifold can begin to leak. This can lead to the code P0456. You should look for a hole or a tear in the code. This is the main problem that can cause the code.
• Vapor Canister Purge Valve– One of the most common causes of the P0456 code is the vapor canister purge valve. It’s really easy to replace. You will need to locate and take out a few clips.
• Fuel Tank Sending Unit– It is possible for the gasket that attaches the fuel sending unit to the gas tank to go bad. This could cause a drop in tank pressure which can throw off the code.
• Fuel Cap– A bad fuel cap can cause the code to be thrown for sure. Often, you’ll get a message informing you that the fuel cap is off even when it is on. It may be worth your time to get that message and a P0456 to ensure you don't waste any money.
• Fuel Filler Neck– There is often a gasket where the fuel filler neck connects with the gas tank. The gasket may dry out especially if the vehicle is in dry conditions. When it dries out, the fuel tank can’t hold pressure anymore.

Ford Focus Diagnostics - P0456

The mechanic will have a lot of different tools at his disposal in order to determine the cause of your Ford Focus P0456. The most commonly used methods to diagnose this code are:

• You will usually find other codes that the mechanic checks to determine if you have any problems. It is easier to diagnose problems if there are more codes. That’s because when they appear together in certain combinations, there will often only be only a few conditions that will throw any combination of codes at one time.
• The mechanic will normally determine what trouble codes are associated with P0456. Check out the EVAP System. It includes the purge valve and line as well as the canister.
• To ensure that the cap can withstand pressure, the mechanic will check it. If you are getting a warning that your gas cap is off, even when it’s on, replacing it will more than likely clear this code.
• Monitoring and checking the fuel tank pressure is a must.
• The mechanic will then perform the following tests after completing the above-mentioned checks:
• A smoke test, and they’ll use a scan tool to confirm that the EVAP solenoids and valves are operating properly.

Here’s a pretty good video on diagnosing these leaks from Scotty Kilmer, if you are interested:

Most common P0456 fixes

Below are the top Focus P0456 solutions:

• Replacement of gas cap
• Replacing EVAP lines
• Replace charcoal canister
• Change the fuel tank

It is best to begin with the gas cap, and then work your way up to the fuel tanks. The gas cap is the most difficult and cost-effective item to replace.

Here’s a great video on How to test your gas tank.

You will need to find the cause of your Ford Focus throwing the code P0456. This should help. Please feel free to add anything below.

Do you consider P0456 to be a serious concern?

While P0456 is not going to cause the Focus’s engine to stop running, it should not be treated lightly. Fuel leaks could be a problem. You should pay extra attention to the level of your fuel tank and ensure that you're not leaking fuel. It is best to have it checked and/or dealt with immediately.

Please leave comments below if you have any suggestions. Thanks!