So, strange thing. I had my last fill-up maybe a week or so ago. I've not touched the gas cap since. However, yesterday afternoon when I started the car up, with around 1/4 tank of gas left, the odometer section started blinking the words "Check Fuel Cap". I was just going to my in-laws not 5 minutes away, so I kept going until I got there.
I turned off the car, and checked the gas cap. Seems to be on securely. I take it off and put it back on again. "click click click..." ok. Let's try again. Turn on the car, and the warning is still there. I tried driving around the block a few times to see if it would reset itself, but it didn't. However, I did find out that if the warning annoyed you, you can always press the trip button and rotate to the Trip A, Trip B, or Oil Life display. But the next time you start the car again, it will go back to the warning.
Like I said, I had not touched the gas cap for a week. So the only thing I can think of that might have set off the warning is the recent temperature change. We've had unseasonably low temperature lately until yesterday, when spring suddenly arrived. Maybe the temperature change caused a change in tank pressure and the car thinks the gas cap is loose? (My car is parked outside)
Anyways, when I went to start up the car this morning, the warning was still there. It stayed on the whole 40km of my morning drive. But when I started the car up again this afternoon, the warning was gone. Hopefully that was enough start-ups/running time/kms for the ECU to reset the warning on its own, and I won't see it again.