Dodge Ram P0456: EVAP System – Small Leak

The most frequent trouble code with the Dodge Ram The Code P0456. This is the trouble code that you get when you plug in your Ram to an OBDII scanner. A P0456 code indicates that there may be a slight leakage in the evaporative exhaust control system. This is often seen with other codes such as P0420 or P0441.

Your Ram'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 Ram, it is actually referring to the amount of pressure lost, and not the physical size of the leak. They can also be very tiny.

Dodge Ram P0456 Description

The universal OBDII trouble code P0456 can be used for all vehicles. It means that no matter what make or model vehicle you have, this code will always mean the same (Ram or not). The code is technically:

System Leakage of Small Size – Evaporative Emission System

The EVAP captures any fuel vapor in the fuel tank. They are then sent to the engines intake for ignition. When there is a small leak in the Dodge Ram’s EVAP system, it will throw the P0456 OBDII Code. If there is a large leak, it’ll throw P0455.

Dodge Ram P0456 OBDII Symptoms

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

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

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 performance of your Ram's engine.

Problem Code Ram P0456

The P0456 trouble code can be triggered by many factors in Dodge Ram. If your Ram 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. 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. There are some clips you will need to look for and then remove.
• 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 Ram P0456 Diagnostics

The mechanic will have a lot of different tools at his disposal in order to determine the cause of your Dodge Ram P0456. These are some of the common diagnostics that can be done for the code

• The mechanic will check to make sure there are no other codes. A mechanic will usually check for additional trouble codes to help diagnose the problem. 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.
• 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.
• Monitor and check the pressure in your fuel tank.
• 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 Ram P0456 fix:

• Replacing the gas cap
• Replacement for EVAP Line
• Replace charcoal canister
• Replacing the fuel tank

You should start with the gas caps and move on to the fuel tanks. This is because the gas caps are the easiest to replace and the least costly.

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

It's a good idea to try and figure out why your Dodge Ram is throwing the P0456 code. We trust this helped. Please feel free to add anything below.

Do you consider P0456 to be a serious concern?

While P0456 is not going to cause the Ram’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. You should immediately take it in for repair or replacement.

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