Hey guys I am trying to diagnose a p0446 on my girlfriends fathers 08 expedition. It originally had a fuel cap light and a code 446. I had him replace the gas cap with one from the dealer and reset the computer. Now the code has returned but not the gas cap light. I am looking for wiring diagrams, pin outs, and any advice to help diagnose the problem. I haven't been able to find anything for this year expedition and am not sure if the f150 information for other years I have found will cross over.
Thanks a lot

 

This is usually the result of a bad vapor canister vent valve.

 

It ended up being that the wires disintegrated apart from corrosion just before the connector. So it was a simple fix thank you.