Jeep Patriot P0456: EVAP System – Small Leak

This is one of the most commonly encountered trouble codes for the Jeep Patriot Is the Code P0456. This is the trouble code that you get when you plug in your Patriot to an internet service. 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 Patriot'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 Jeep Patriot, it is actually referring to the amount of pressure lost, and not the physical size of the leak. They can also be very minor.

Jeep Patriot P0456

The universal OBDII code P0456 can be used to diagnose trouble codes. It means that no matter what make or model vehicle you have, this code will always mean the same thing. Technically, the code stands for:

System Leakage of Small Size – Evaporative Emission System

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

Jeep Patriot OBDII Code Symptoms

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

The fuel filler tube or around the fuel tank should smell particularly strong.

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 technology deals only with the fuel vapor. It does not impact the performance of your Patriot.

Patriot P0456 Trouble Code Reasons

P0456 Trouble code can occur for many reasons in your Jeep Patriot. If your Patriot 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.

• 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 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 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. It can lower the tank pressure, which could throw out 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. It is possible for this gasket to dry, particularly if vehicles spend a lot of time in dry environments. When it dries out, the fuel tank can’t hold pressure anymore.

Diagnoses for Jeep Patriot P0456

To diagnose the problem with your Jeep Patriot's P0456, a mechanic can use a variety of tools. The most commonly used methods to diagnose this code are:

• The mechanic will check to make sure there are no other 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. Take a look at the EVAP system. These include the line and purge valve.
• 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.
• 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

These are some of the most popular Patriot P0456 fix:

• Replacement of gas cap
• Replacement for EVAP Line
• Replace charcoal canister
• Change 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 check your gas cap.

You will need to find the cause of your Jeep Patriot 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 Patriot’s engine to stop running, it should not be treated lightly. There could be fuel contamination. Check your tank regularly to make sure there is no fuel leaking. You should immediately take it in for repair or replacement.

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