I have a 2006 Explorer and a couple of weeks ago my check fuel cap light went on and then a couple of days later the check engine light went on. I ran the codes and I get P0457 I have a small EVAP leak and a large leak. I am looking for anyone else that has had this code and what they did to fix it. I have a new cap and was going to put it on but I also have the small leak that I have to deal with. I am thinking it is the solenoid because I have had trouble in the past putting fuel into my tank because the tank isn't venting properly and the venting gases trip the fuel shutoff in the gas pump. Any help anyone can provide I would appreciate.

 

I took my explorer to a local shop that does smoke testing and for $40 they tested it and told me what was wrong. It ended up being the seloniod valve near the tank. I replaced it in about 10 min for about $80 for the OEM part.

 

Got the P0457 code on my '04 E350, 5.4L, 67k mi. I found this thread via web search.
Bought the van two years ago and experienced the same problem refueling as described here. As mysteriously as the 20 minute plus fill-ups started, they disappeared after many months of hassle. Last week I got the "check fuel cap" MIL and retrieved the code. Put a cheap replacement cap on and cleared the code. So far, so good.
I don't think I'm out of the woods yet though. From the sounds of things, I'm looking at the same repair you did. My question is, what "valve" did you replace? On the E350 there is a Fuel Tank Pressure sensor that monitors pressure/vacuum differential. It's directly on the tank. There also is a Vapor Management Valve, but I think it controls excessive tank pressure, not vacuum or leak.
It would help out greatly if you could be specific as to what part you replaced on your Explorer.

Thanks for any input.