What Does The Jeep P0456 Engine Code Mean? Best And Quick Fixes

Part of owning a vehicle is keeping up with its maintenance and dealing with its problems. Jeeps are reliable vehicles, but they can sometimes be susceptible to problems.

Jeep P0456

Engine Codes might be annoying and troublesome, but with the help of these codes, the owner doesn’t have to guess what’s wrong with their vehicle. They can search for the code on the internet and immediately tell the problem.

So what’re you waiting for? Let’s dive into this article so that you can fix the problem at hand.

What Does the Jeep P0456 Engine Code Mean?

The Jeep P0456 Engine Code means the vehicle has detected a small leak in the Evaporative Emissions System (EVAP). Car companies implemented this system in vehicles in the 1970s. Its primary purpose is to prevent gasoline vapors from escaping into the environment from the tank and fuel system.

The EVAP system is sealed. It recycles the fuel vapors through the engine instead of letting them out into the environment, thus preventing unnecessary emissions. 

Symptoms of the Jeep P0456 Engine Code

These are the signs of the P0456 Engine Code:

  • The Check Engine Light is on.
  • You might notice a fuel smell coming from the engine.
  • Decreased fuel economy.
  • Increased emissions.

How to Diagnose the P0456 Engine Code

You can diagnose the P0456 Engine Code in the following ways.

  • Check the vehicle’s computer through an OBD-II Scanner.
  • Inspect the Purge Valve system and hose connectors for damaged or loose connections.
  • Perform a smoke leakage test on the fuel vapor system.
  • Check the fuel cap for any leaks.

What Causes the Jeep P0456 Engine Code?

The Jeep P0456 Engine Code has several causes. We’ll help you figure out the exact cause so you’ll know what to do.

Leaking or damaged EVAP hose

One of the most common causes of the P0456 Engine Code is an issue with the EVAP hose.

Vent lines pass vapors from the fuel tank to the vapor canister, where the vapors are stored until the vehicle is started. Leakage of the EVAP hose may cause the vapors to escape.

Loose or damaged Gas Cap

The P0456 Engine Code can also be caused by a damaged or loose gas cap. The gas cap of the vehicle’s fuel tank can get damaged due to environmental factors, which can cause vapors to leak.

Problems with the Purge Vent Valve or Charcoal Canister

The Purge Vent Valve is a solenoid controlled by the engine computer. The vehicle’s fuel tank is connected to the charcoal canister, and some of the fuel vapors are temporarily stored in it.

When the vehicle is off, the Purge Vent Valve is closed. When you turn it on and fully warm it up, the engine computer opens the Purge Vent Valve. This allows some fuel vapors to be released from the charcoal canister and used in the engine. When there is a problem, these vapors can escape and cause the P0456 error code.

Leaking Fuel Tank

One of the tell-tale signs of the P0456 Engine Code is the smell of fuel around your vehicle. This could be due to the gas tank in your vehicle leaking.

The fuel tank in a vehicle is sometimes overlooked in its importance, but any damage to it can be detrimental to the vehicle’s range and safety. Leaking fuel can also become a fire hazard for occupants.

If your vehicle’s fuel tank leaks, your top priority should be fixing it immediately.

Damaged Vent Control Valve

The Vent Control Valve is also a part of the EVAP system. It controls the outside air streaming in and out of the charcoal canister. In some Jeeps, it’s called the Canister Close Valve(CCV)

Because it’s located on the vehicle’s underside, the Vent Control Valve often fails due to corrosion or damage caused by environmental factors and normal driving, prompting the Jeep P0456 Engine Code.

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How to Fix the Jeep P0456 Engine Code

Now that we know what the Jeep P0456 Engine Code is and what causes it, we can get on to the fixes.

Replacing or tightening the Gas Cap

By far, the most simple solution to the P0456 Engine Code is just replacing the gas cap if it is damaged or tightening it if it’s loose.

Fuel in a vehicle’s gas tank evaporates at a very high rate, so sometimes even small vapors can escape from the gas cap, even if it has a tiny opening. These vapors are also flammable and can be a fire hazard. If your gas cap is damaged, immediately replace it.

Fixing damaged hoses

If your Jeep’s EVAP hoses are damaged or chewed through, they should be fixed or replaced with new ones. Checking them can also tell you if they are damaged or just disconnected.

If they’re disconnected, you can easily fix them.

Fixing or replacing the Purge Vent Valve and Charcoal Canister

The wiring of the Purge Vent Valve is quite sensitive to environmental factors, so if it’s damaged or has short-circuited, it should be replaced.

The charcoal canister can go bad if excess gasoline gets absorbed, so in this case, it should be replaced.

Fixing the Vent Control Valve

The vent control valve is a sensitive device that can get damaged due to corrosion. If this happens, you should replace it immediately. The vent control valve may sometimes be stuck open or closed due to software issues. In this case, you can take it to a professional who will perform a reset to fix it.


There you have it, folks, a complete rundown of the Jeep P0456 Engine Code. Even though this code might look like a big problem at first, it is quite minor. But if you don’t properly diagnose and repair it, it may become a bigger problem. 

You should consult a professional if you have trouble finding the exact solution. 


Is the P0456 Engine Code only for Jeeps?

As all cars have EVAP systems nowadays, any car can get this code. The fixes might not be the same, but you can rely on general information to help you.

Can I drive after getting the Jeep P0456 Code?

Yes, because this is a minor code, your vehicle can remain drivable for some time. It will result in a reduced economy and higher emissions. In addition to that, leaving it unaddressed could also lead to other problems.

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