A funny thing happened once cold weather hit KY. After my 2011 cooper s was parked for 12 hours, I left work and when I started it up and the requisite tones (freeze warning/seatbelt chime) came on,one of those tones came on with a deafening bang. I don‘t know which of those tones made the sound. Only happened once. Next morning same thing. Never had this problem before. I had my car in for a service today, told them about this. They hooked up their device and said no error code came up and of course, it didn’t make the sound after driving it over 100 miles for a service. Anyone have this problem or possibly know hat it might be. It sure scares the hell out of me.