Chrysler 300 P0456: EVAP System – Small Leak

This is one of the most commonly encountered trouble codes for the Chrysler 300 The Code P0456. The trouble code refers to a number you get when you plug in your 300 to a 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.

The P0456 issue is not usually a threat to your 300'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 Chrysler 300, it is actually referring to the amount of pressure lost, and not the physical size of the leak. They can also be very tiny.

Chrysler 300 P0456 Definition

The OBDII universal trouble code is P0456. The code can be used regardless of the make and model of the vehicle. Technically, the code stands for:

System Leakage in the Smallest Detail – Evaporative Emission System

The EVAP captures any fuel vapor in the fuel tank. They are then sent to the engines intake for ignition. When there is a small leak in the Chrysler 300’s EVAP system, it will throw the P0456 OBDII Code. If there is a large leak, it’ll throw P0455.

Chrysler 300 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.

Particular attention should be paid to the smell of fuel near the fuel tank or fuel filler tube.

The EVAP process deals with fuel vapors directly. 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 engine.

300 P0456 Trouble Code Causes

P0456 can be triggered by many factors in your Chrysler 300. If your 300 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.

• Evap System Hose– 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 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. You will need to locate and take out a few clips.
• Fuel Tank Sending Unit– It is possible for the gasket that attaches the fuel sending unit to the gas tank to go bad. It can lower the tank pressure, which could throw out 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.

Chrysler 300 Diagnostics - P0456

The mechanic can use a range of instruments to determine the cause of your Chrysler 300's P0456 error. The most commonly used methods to diagnose this code are:

• The mechanic will usually check for any additional trouble 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.
• Once the mechanic has determined the trouble codes associated with P0456, 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:

The Most Popular P0456 Fixes

Below are the 300 most popular P0456 fixes.

• Replacement of gas cap
• Replacing EVAP lines
• 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 Chrysler 300 is throwing the P0456 code. This information is hoped to be helpful. 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 300’s engine to stop running, it should not be treated lightly. There could be fuel contamination. Check your fuel level to make sure it is not leaked. It is best to have it checked and/or dealt with immediately.

Feel free to add anything to the article by leaving a comment. Thanks!