I had that happen on my Ford truck. Back in Jan. we had a severe cold snap and a pretty good snow. The truck just sat there until everything melted. Later I started getting 'the light'. Long story short, some kind of rodent had nested on top of the tank during the bad weather and predictably got hungry and decided to bite every hose in the EVAP system on top of the tank. The lowered the tank (fairly easy on the truck) and replaced the rubber parts with the factory items. The fee was $950. Tell you what, I don't know if there may have been some damage there before that but the truck, which has always run great, now runs even better and I noticed right away it looked like I was getting better mileage. Today I noticed that I got 200 miles on the first 1/2 tank, and that's all 'city' driving. Its a 2007 F-150 with 4.2L V6 and 5-spd manual. It gets 15-17 mpg in my usual driving around running errands, picking up stuff, etc.
Anyway, once I learned what really happened and took another look at the tank area, I decided if it happens again I would take it somewhere else other than a Ford dealer. I think I could have had it done for half what I paid.
I'm not buying that crap from the shop that the hose can't be replaced - that's bull. Hell, you could wrap electrical tape around the sections with holes and that would work for years. Its nothing more or less than fuel line hose and it can be bought in all the diameters you're dealing with.
