I am having the same problem. It started a few weeks ago, I called a dealer and they told me that I most likely didn't tighten the gas cap hard enough. I always do, but I said ok. I reset the code and filled up again. Everything was fine for a few days. Then it came back again. I did the same thing, and again it was fine for a few days but then came on again. For now, I am just ignoring it since everything seems to work fine, but I will give dealer a call sometimes soon.

Please let me know if you find out what's up!