Came out to my 3-month-old S 75D Sunday afternoon to find it completely unresponsive. Wouldn't unlock, would let me disconnect the charger, nothing. Called Tesla, and the tech said the car had registered alerts about the 12-volt battery, but I hadn't gotten any. I got lunch with it on Saturday and parked it back in the garage with a nearly 90% charge with nothing unusual. A Ranger came out today and got it up and running. He replaced the 12-volt, thinking it had a bad cell, but after driving it around for a while, he did some more testing and now fears it has a bad module or fuse or something. He's going to look into seeing if it is really a firmware issue but, barring that, will arrange for it to be towed to the nearest Service Center (2.5 to 3 hrs away). So, it's working now and might be okay with a firmware update, or it might become unresponsive again at any time. Yikes. This is the same car that had an unresponsive driver's door handle just a few weeks ago fixed by the same Ranger. Nice guy. Seems very competent, just in a tough spot.