I have an 05 S-type R with 130k on it. I've experienced the misfire codes talked about in the cold soak posts below but for the last 2 years have had something more serious. If the car sits for more than a few days in below 25°F weather and is then started and driven less than 15 miles, the engine may ice internally and on restart be hydraulically locked. The symptoms are the starter not turning and then the electrics dimming like a dead battery. Sometimes, if the car hasn't sat too long, I can bump the starter and after multiple attempts break through the lock. But if I park it overnight the only solution is to tow it to a heated garage and let it sit overnight.
The dealer has been through electrical and fuel systems and found nothing wrong. They tell me the supercharger is drawing in moisture, which then condenses and runs into the open cylinder, freezes and locks the engine. It ran 8 years in Wisconsin winters before this problem started. I'm suspicious of a change in fuel but being in a corn state have no non ethanol option.
Anyone else seeing this?