My PNP switch did this only on Chicago's coldest winter days (0 F or below), for 2 winters. I exercised it and reset the light maybe 3 times. During the 3rd winter it started to act up when it was not particularly cold. Sometimes the gears would engage erratically and I figured the trans might get damaged. So I had it replaced for about $125 and took back the old part. Not only were the tracks coated with grease but they were worn nearly to nothing. The car's mileage was then about 100K with mainly city/suburban driving. I've learned this component fails according to time and use on various brands of cars and is replaced routinely.