I spent 3 days with friends up at Raquette Lake in the Adirondacks. The bike (2001 S4) performed flawlessly the entire time...until I got about 20 miles from my house. It was a really hot day and it was the end of an approx. 250 mile trip. The coolant light came on. It was about 2 pm and I was at the exit nearest one of my longtime watering holes. So, I rolled into the Hartford Road Cafe in Manchester, CT. Shut it down and went in and had a beer and sandwich. My plan was to let the bike cool down then ride it as far as possible until the light came on again.....repeat until I got it home. So, after lunch, I set out once again. The light never came on. Got home without incident. The next day I checked the coolant level with the bike on the side stand. (Not sure if that's the way you are supposed to check coolant. Upright?) When I took the cap off the coolant was up to the top. I'm guessing the issue involved a sensor but I have no idea and it doesn't seem to be happening anymore. Any advice or theories?