Hyundai Tucson P0456: EVAP System – Small Leak

This is one of the most commonly encountered trouble codes for the Hyundai Tucson Is the Code P0456. This is the trouble code that you get when you plug in your Tucson to a OBDII scanner. A P0456 code indicates that there may be a slight leakage in the evaporative exhaust control system. This code is often found with or related to P0420,P0441 and, very rarely, P0440.

The P0456 problem is not usually a threat to your Tucson'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 Hyundai Tucson, 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.

Hyundai Tucson P0456 Description

P0456 stands for a universal OBDII Trouble Code. 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 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 small leak in the Hyundai Tucson’s EVAP system, it will throw the P0456 OBDII Code. If there is a large leak, it’ll throw P0455.

Hyundai Tucson OBDII Codes Symptoms

The P0456 code is usually not accompanied with any other symptoms than those listed. The smell of gas And the service engine soon light.

The fuel tank and fuel filler tubes should smell particularly strong.

Fuel vapors are dealt with directly by the EVAP. 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 Tucson's engine.

Tucson P0456 Trouble Code Reasons

Your Hyundai Tucson can trigger the P0456 code for trouble. There are many reasons. If your Tucson 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 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 code P0456. 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. 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. It is possible for this gasket to dry, particularly if vehicles spend a lot of time in dry environments. When it dries out, the fuel tank can’t hold pressure anymore.

Hyundai Tucson Diagnosis - P0456

The mechanic will have a lot of different tools at his disposal in order to determine the cause of your Hyundai Tucson P0456. The most commonly used methods to diagnose this code are:

• A 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 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.
• 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:

Most common P0456 fixes

These are some of the most popular Tucson P0456 solutions:

• Replacement of 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 easiest to replace and the least costly.

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

We wish you all the best in finding out why your Hyundai Tucson is throwing the P0456 code. This should help. You can add any additional information by leaving a comment.

Are P0456 Serious Concerns?

While P0456 is not going to cause the Tucson’s engine to stop running, it should not be treated lightly. There could be fuel contamination. Check your tank regularly to make sure there is no fuel leaking. You should immediately take it in for repair or replacement.

Please leave comments below if you have any suggestions. Thanks!