I've had that code several times on my '05. The fix was always the same: remove and reinstall the cap. The code would clear on it's own in a few days, or I could clear it manually if I didn't want to see the MIL.
Been two days of driving around to work and back (about 40-50 mile) a day. Light hasn't came back on. If it doesn't come back on tomorrow then I guess it was the cap.
I got this code this morning when I was about to head to work...@ 4am. Car hasnt been touched under the hood in months. Only thing that happened was it rained yesterday and car sat in the rain. I fired it up this morning and got a loud pop out the exhaust and running really rough. First thing I checked was gas cap, it was tight. Also it wouldnt let me clear the code. I didnt have anytime to troubleshoot anything until I get off this evening. Anyone seen something like this?
Ok, just had my wife check the floor board, its dry. Plus Im not getting any of the symptoms associated with the wet SJB. All eletronics work fine, just got the P0456 code and running rough. I plan to pull the carbon canister when I get home and inspect all vacuum lines as well.
the car sat at my work when it rained...it wasnt a heavy rain but it was off and on. After I got home and the car went in the garage is when the rain got heavy.