Dodge Avenger P0456: EVAP System – Small Leak

This is one of the most commonly encountered trouble codes for the Dodge Avenger Is the Code P0456. This is the trouble code that you get when you plug in your Avenger to a OBDII scanner. The code P0456 indicates that the evaporative emissions control system has a tiny leak. This code is often found with or related to P0420,P0441 and, very rarely, P0440.

Your Avenger's driveability is generally not affected by P0456. 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 Dodge Avenger, 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.

Dodge Avenger P0456 Definition

P0456 stands for a universal OBDII Trouble Code. The code can be used regardless of the make and model of your vehicle. Technically speaking, it stands for:

System Leakage in the Smallest Detail – Evaporative Emission System

The EVAP system collects fuel vapor from fuel tanks and then sends it to the intake to ignite the engine in normal combustion. When there is a small leak in the Dodge Avenger’s EVAP system, it will throw the P0456 OBDII Code. If there is a large leak, it’ll throw P0455.

Dodge Avenger P0456 OBDII Code Symptoms

The P0456 code is usually not accompanied with any other symptoms than those listed. The smell of gas And the service engine soon light.

Particular attention should be paid to the fuel tank or fuel filler tube smell.

Fuel vapors are dealt with directly by the EVAP. 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 performance of your Avenger's engine.

Avenger P0456 Troublecode Causes

P0456 Trouble code can occur for many reasons in your Dodge Avenger. If your Avenger 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.

Below are the top most probable problems that could throw the code. These were listed alphabetically, in some order.

• Evap Hose– 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. It should be checked for tears or holes. This is the leading cause of 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'll need to identify and remove 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.

Dodge Avenger Diagnostics - P0456

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

• The mechanic will usually check for any additional trouble codes. 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. These include the line and purge valve.
• A mechanic will examine the gas cap and verify that it is able to withstand high pressure. 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

These are some of the most popular Avenger P0456 solutions:

• Replacement of gas cap
• Replacement for EVAP Line
• Replace charcoal canister
• Replacing 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 Dodge Avenger 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 Avenger’s engine to stop running, it should not be treated lightly. Fuel leaks could be a problem. Check your tank regularly to make sure there is no fuel leaking. It is best to have it checked and/or dealt with immediately.

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