At least on mine the hoses are plastic, so you should inspect them carefully for cracks.

 

It could be a clogged hose. I get that code from time to time because I had the wrong fuel pump on my truck, and when everything expanded the canister became saturated with gasoline. I have new filters, I just need to get some charcoal (bone, not wood) and perform a changeout.

 

When I got that code... it was a bunch of cracked hoses. The hoses on the solenoid itself was pretty badly cracked near the nipples ...

Here's a couple of pictures...

Doesn't look too bad...


Then I rolled it over...



I replaced those thinking it was fixed - and was flaming mad when the code was thrown again.

I continued the search and the "real" problem was where the hoses connect to the canister under the cab. I had to undo 4 bolts to pull it out - but the hose was pretty much destroyed. I don't have any pictures, but they were in worse shape than the hoses shown above.

Don't bother calling the dealer either... They wanted a BUNCH of money for their pre-formed hoses... almost 100 bucks if I remember correctly. Go to an auto parts store and get all the hose for under 10 bucks.

You would also be well served with some water-based lube to get the new hoses on the canister and the plastic line that goes up under the hood.

Good luck!
Cartman