Jeep Grand Cherokee P0455: EVAP System → Leak Detected (Large)

The most frequent trouble code with the Jeep Grand Cherokee Is the Code P0455. This code is used to refer to the trouble code for your Grand Cherokee. If there's a problem, P0455 means that it is. Large leak In the evaporative emissions control system (EVAP). This code is often found with or related to other codes such as P0420 and P0430.

P0455: EVAP System → Leak Detected (Large)

Your Grand Cherokee's driveability is generally not affected by P0455. Certainly anytime the service engine soon light is on, it’s good to deal with it as soon as possible though.

Jeep Grand Cherokee P0455 Description

The universal OBDII code P0455 can be used to diagnose any problem. The code is universal, meaning that it will be the same regardless of the make and model of your vehicle (Grand Cherokee). Technically the code is:

System Gross Leak Evaporative Emission System

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

Jeep Grand Cherokee OBDII Code Symptoms

A P0455 Code will usually not cause any symptoms except the ones listed below. The smell of gas The service engine soon light. It is possible to notice a slight dip in fuel economy.

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.

Grand Cherokee Trouble Code P0455

Many things can trigger the P0455 code in Jeep Grand Cherokee. The most frequent problems that trigger this code are:

• Evap System 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 P0455 code. 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 P0455 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.
• The Faulty Charcoal Caister– The charcoal canister is often the cause of P0455.
• 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 P0455 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.

P0455 Diagnose- Jeep Grand Cherokee

To diagnose the problem with your Jeep Grand Cherokee's P0455, a mechanic can use a variety of tools. These are some of the common diagnostics that can be done for the code

• Check with the mechanic to determine if any additional trouble codes are present. 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.
• Once the mechanic has determined the trouble codes associated with P0455, he or she will usually 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.
• 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:

While the trouble code may state that there is a “large leak” in the EVAP system of your Jeep Grand Cherokee, the actual leak will most likely still look rather small. The “large” really is referring to how much pressure is being lost.

P0455 is the most common fix

These are some of the most popular Grand Cherokee P0455 repairs:

• Replacing the gas cap
• Replacing EVAP lines
• 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 most cost-effective and easiest to replace.

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

We wish you all the best in finding out why your Jeep Grand Cherokee is throwing the P0455 code. This should help. Please feel free to add anything below.

Are P0455 Serious Concerns?

While P0455 is not going to cause the Grand Cherokee’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.