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

This is one of the most commonly encountered trouble codes for the Jeep Cherokee The Code P0455. This code is used to refer to the trouble code for your Cherokee that you get when it's plugged in to an OBD2 scanner. The number has to do to with the emissions system. The trouble code P0455 indicates that the emission system is malfunctioning. Large leak In the evaporative emissions control system (EVAP). It is frequently found alongside, or closely related to, other codes like P0420/P0430/P0441 and most often, P0440.

P0455: EVAP System → Leak Detected (Large)

Your 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 Cherokee P0455 Description

The universal OBDII code P0455 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 (Cherokee). The code is technically:

System Gross Leak Evaporative Emission System

The EVAP system collects fuel vapor from fuel tanks and then sends it to the intake to ignite the engine in normal combustion. When there is a large leak in the Jeep Cherokee’s EVAP system, it will throw the P0455 OBDII Code.

Jeep Cherokee OBDII Codes Symptoms

The P0455 code is usually not accompanied with any other symptoms than those listed. The smell of gas The service engine soon light. The slightest drop in fuel economy may also be noticeable.

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.

Cherokee P0455 Trouble Code Causes

Many things can trigger the P0455 code in Jeep Cherokee. These are some of the more common issues that can trigger the P0455 trouble code in your Jeep Cherokee:

• Hose for Evap System– 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. It should be checked for tears or holes. 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. You will need to locate and take out a few clips.
• A Faulty Canister of Charcoal– 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. You may not get the message but a P0455. 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 Cherokee

The mechanic will have a lot of different tools at his disposal in order to determine the cause of your Jeep Cherokee P0455. These are some of the common diagnostics that can be done for the P0455 code.

• The mechanic will usually check for any additional trouble 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 P0455. Check out 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.
• 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:

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

Most common P0455 fixes

Below are the top Cherokee P0455 fix options:

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

It is best to begin with the gas cap, and then work your way up to the fuel tanks. The gas cap is the most difficult and cost-effective item to replace.

Here’s a great video on How to check your gas cap.

It's a good idea to try and figure out why your Jeep Cherokee is throwing the P0455 code. This should help. Please feel free to add anything below.

Do you consider P0455 to be a serious concern?

While P0455 is not going to cause the Cherokee’s engine to stop running, it should not be treated lightly. There could be fuel contamination. 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.