I have a 2012 Ford Escape with a filler hole with no cap. The code said I had a leak in the filler hole. Did a smoke test and found no leaks. After doing a little research, I found that Ford has solved this problem THEY CREATED! That gas cap worked. There is no more warning code. I also recommend purchasing a 1 1/2 inch ID 1/8 inch thick (0.85 cents) o-ring to ensure a good seal. PROBLEM SOLVED.