Now when the issue of P0456 comes up, it's a generic term for the many points of entry and exit the Fuel system has to vapors to escape and if the volume is too great - the system throws a code for Leak, doesn't mean it's dripping and ready to ignite - but the check engine light comes on due to this condition.
So, the purge valve is a good start, and may fix it, but if it doesn't, please don't go throwing money away because there may be other areas you need to check in the system -before you just go try another part, then another part then a whole set of parts you might as well buy the whole car all over again...once piece at a time, so the song goes...
I'm referring to the Fuel Tank Fill valve, that little thing that keeps people from sticking their fingers in there and or idiots trying to siphon gas - being the cheapskates they are...
Just check the valve and make sure it SEATS - as if; it can close and seat to form a seal. Because? Things like - dirt, debris, dust sand - snow ice and water can get in there affecting this seal and degrade the seal - even the "mouth" of the unit is in two pieces, one screws into the other so it can even be mounted in that little dimple - so it's best to "start the engine" and let it run then go back there and work that vane/seal flap to see if you can hear a small vacuum being formed or if there is a hiss in the area. Then also check the front system too, there is a nylon hose its rigid hose, that comes from the valve to the engines intake manifold just under the throttle body and snorkel. If that has come loose - it can set this code too.