Dodge knows about this but they only cover it under warrenty even
though their hoses are crap.
Check ALL the hoses from your throttle body and manifold that have anything to do with the emission gas canister. I had to change ALL of mine! It looked like they just rotted away.
And heres the kicker!!! Dodge has a "hose replacement kit" for just this problem. It covers 03 Dakotas, Durangos and Caravans,
but its only covered "under warrenty" i.e. 3yr/36000 mile. Mine showed the code at 38000 miles.........not covered
P0456 is a small leak in emission system, check all hoses.
Thanks Dodge!!!