Jeep Wrangler P0456: EVAP System – Small Leak

The most frequent trouble code with the Jeep Wrangler Is the Code P0456. This is the trouble code that you get when you plug in your Wrangler to an 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 P0420 or P0441.

The P0456 issue is not usually a threat to your Wrangler's 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 Jeep Wrangler, 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 Wrangler P0456 Definition

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 be the same regardless. Technically the code is:

System Leakage in the Smallest Detail – 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 Wrangler’s EVAP system, it will throw the P0456 OBDII Code. If there is a large leak, it’ll throw P0455.

Jeep Wrangler P0456 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 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 Wrangler engine.

Problem Code Wrangler P0456

P0456 is a trouble code that your Jeep Wrangler can trigger. There are many reasons. If your Wrangler 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.

• Hose of the Evap System– The hose that carries the fuel vapor from the fuel tank to the intake manifold can begin to leak. The P0456 error code will be generated. It should be checked for tears or holes. This is one of most frequent causes for 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. You may not get the message but a P0456. This will save you time and 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.

Diagnoses for Jeep Wrangler P0456

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

• It is common for the mechanic to check for additional 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. Take a look at 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:

The Most Popular P0456 Fixes

Below are the top Wrangler P0456 fix requests:

• Replacement of gas cap
• Replacing a 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.

You will need to be patient when trying to figure out why your Jeep Wrangler is throwing the code P0456. This should help. Please feel free to add anything below.

Are P0456 Serious Concerns?

While P0456 is not going to cause the Wrangler’s engine to stop running, it should not be treated lightly. Fuel leaks could be a problem. Check your fuel level to make sure it is not leaked. You should immediately take it in for repair or replacement.

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