I had mine go dead after sitting for about a week. I put my battery charger on it and it showed that the battery was just barely over 4 volts. It took a couple hours for the battery to charge up enough to start (I had it on a slow charge). When I did get it started I had no power steering and gave a warning "steering assist fault service required". I brought it in to the dealer (hard to steer) and they were very helpful. They told me there is a TSB for the battery drain but said it took a complete computer reflash that would take a couple hours. They sent me home with a nice 21' Explorer ST. Then the next day they said they were having issues with the update on the Ford Pass and had to work with the Ford engineers to get it figured out. It took 2 more days for them to get it figured out with their mechanics and the Ford engineers learning what to do with my truck. I asked them to test the battery and they said it tested as good. I haven't had the issue since and I have had it sit for a week one other time since.