My 97 850 wagon (glt) occasionally engages winter mode on its own. Actually, the first time it happened, about 3 weeks ago, I pushed the winter mode switch and got the blinking arrow and the check engine light. It has twice engaged winter mode on it's own since then. Accompanied by the flashing arrow. Each time the system has eventually reset itself but not the check eng light (I don't think this can be done except by Volvo service personnel). I bought this car used about 1,500 miles ago and now suspect this was an ongoing problem for the previous owner. I, too, would be grateful for any feedback from others that have experienced this problem and know its cause/fix.

BTW I put a small square of black electrical tape over the check engine light. It's just too annoying and I can wait until the next service interval (60k miles in a month's time) before paying for diagnostics.