I have a 2011 with the same issue. It's throwing a P2400 and P2418 code. I've replaced both solenoids, one under the hood, and one in the EVAP assembly, the leak detection pump, the evap canister, and the gas cap. I've also cut away the harness sheathing to look for corrosion. Can't keep the codes from coming back after a power cycle.
Did you solve this?