Jeep Cherokee P0456: EVAP System – Small Leak

This is one of the most commonly encountered trouble codes for the Jeep Cherokee Is the Code P0456. This is the trouble code that you get when you plug in your Cherokee 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 Cherokee'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 Cherokee, 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.

Jeep Cherokee P0456 Description

The universal OBDII code P0456 can be used to diagnose trouble codes. The code can be used regardless of the make and model of the vehicle. 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 Cherokee’s EVAP system, it will throw the P0456 OBDII Code. If there is a large leak, it’ll throw P0455.

Jeep Cherokee OBDII code Symptoms

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

Cherokee P0456 Trouble Code Causes

The P0456 trouble code can be triggered by many factors in your Jeep Cherokee. If your Cherokee 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 for 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. 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.

Diagnoses for Jeep Cherokee

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

• A mechanic will often 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. 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.
• Monitor and check the pressure in your fuel tank.
• Following the inspections and repairs, the mechanic will conduct two more tests.
• 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 more common Cherokee P0456 solutions:

• 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 check your gas cap.

You will need to find the cause of your Jeep Cherokee throwing the code P0456. We trust this helped. You can add any additional information by leaving a comment.

Do you consider P0456 to be a serious concern?

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

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