Replaced gas cap with one from the dealer, light went out, but came back on a few days later. Went to dealer and had a module? in the gas tank replaced. Cost $500. Three months later, light on again and again it was something in the gas tank that had to be replaced. Cost $200
Check engine light came on...filled the tank up with gas, closed the gas cap and light turned off.
Had the engine light checked and they said it is the gas cap.