Honda Pilot P0456: EVAP System – Small Leak
This is one of the most commonly encountered trouble codes for the Honda Pilot The Code P0456. This is the trouble code that you get when you plug in your Pilot to a OBDII scanner. The code P0456 indicates that the evaporative emissions control system has a tiny leak. It is sometimes found along with other codes such as P0420 or P0441.
The P0456 issue is not usually a threat to your Pilot'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 Honda Pilot, 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.
Honda Pilot P0456 Definition
The OBDII universal trouble code is P0456. It means that no matter what make or model vehicle you have, this code will always mean the same thing. Technically speaking, it stands for:
System Leakage of Small Size – 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 Honda Pilot’s EVAP system, it will throw the P0456 OBDII Code. If there is a large leak, it’ll throw P0455.
Honda Pilot P0456 OBDII Code 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.
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. But, it won’t affect the way the engine itself runs. You will not notice any changes in the performance of your Pilot's engine because the EVAP system only deals with fuel vapor.
Problem Code Pilot P0456
P0456 can happen for many reasons in Honda Pilot. If your Pilot 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.
These are some of the most frequent problems that can throw off the code. They're listed in alphabetical order, from the most likely to the least.
- 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 code P0456. 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. There are some clips you will need to look for and then remove.
- 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 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.
P0456 Diagnosis- Honda Pilot
To diagnose the problem with your Honda Pilot's P0456, a mechanic can use a variety of tools. The most commonly used methods to diagnose this code are:
- The mechanic will check to make sure there are no other 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.
- The mechanic will normally determine what trouble codes are associated with P0456. Take a look at 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.
- 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 most commonly used Pilot P0456 solutions:
- Replacing the gas cap
- Replacing EVAP lines
- Replace charcoal canister
- Change 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 Honda Pilot is throwing the P0456 error code. We trust this helped. Please feel free to add anything below.
Are P0456 Serious Concerns?
While P0456 is not going to cause the Pilot’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. You should immediately take it in for repair or replacement.
Please leave comments below if you have any suggestions. Thanks!
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