Running a low tank of gas isn't good in cold weather.

I just threw ECU code 90, or what I think is 90 (I can't tell if it's 9 or 90, but w/e) Which as far as I know is a problem with the evaporation devices in the gas tank.. or at least thats what I think the evaporative emissions control system is....


I went to fill up and my cap seemed to not be tightened correctly, I wonder if that could have done it...