I would buy one of those little suction like things at an autoparts store (the one with the little balls that float up in it) and check your coolant to see if it's within specs. If you're having really, really cold weather and your coolant is starting to have ice crystals in it due to it not performing up to spec, you could throw that code. Not to mention that if temps drop too far, you could freeze your block and that would mean a new engine...not worth it. I would say that once your coolant is warmed up and you reset the code, you shouldn't have any issue, but I would check your coolant just the same.
--
1998 S70 T5 Emarald Green Metallic, 2004 V70 2.5T Ruby Red, Previous Owner of Black '94 850 Turbo Wagon. My cars have been running so well lately they've got me worried.