Did you have your window down or your door possibly open when refueling the car? That Gas cap light works off of sensors that detect gas fuemes. Since it has been colder out, gas fumes tend to be more potent, at least to my nose. This may have cause the light to come on. In most cars I have worked on, this light turns itself off when It no longer senses the problem. It doesn't throw a code in computer that has to be cleared or reset. If it doesn't come back on the I say your okay and that was the problem. If it does come back on and if what I described is not the problem them I don't know what else to tell you other than take it to the dealer. Good Luck!