- Evap System Hose– The hose that carries the fuel vapor from the fuel tank to the intake manifold can begin to leak. This will cause the P0456 code. Look for either a tear or hole in it. This is one of the most common issues that causes 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 a few clips that you need to find and 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 can reduce tank pressure and throw 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. If you are getting that message, plus a P0456, it may save you a ton of time and money to replace the fuel cap and see if it goes away.
- Fuel Filler Neck– There is often a gasket where the fuel filler neck connects with the gas tank. This gasket can dry out, especially with vehicles that spend their time in dry climates. When it dries out, the fuel tank can’t hold pressure anymore.
I have three codes P0440 P0441 and had the P0456. More than likely, there are a few fixes that will help out. The EVAP hose and the Natural Vacuum Leak Detection Detector could have gone bad. The one hose from the charcoal/vapor canister is exposed and can be dry rotted causing pin holes or cracks. The NVLD detector could be bad as well causing the code too. Check the gaskets and the lines.
I cycled the key three times on/off and it showed the codes on the dash display and it indicated the P0440 & P0441 codes this time.
I ordered the NVLD from rockauto.com and the hose to replace the one that is there.
Hope this helps out.
