Well, this past weekend I drove from the Willamette Valley over to the Oregon Coast. On the drive through the Coastal Range, there is a true Dead Spot for WiFi and cell service---about 20 miles from the 101 intersection. On the way over I got the dreaded SOS Call system failure. I spent two nights on the coast and did not use the car at all (I had to recharge the battery at an L2 station in order to make the trip back comfortably). When I started the car up to return the "SOS CALL" error had cleared. On the drive back, passing through the same area, the error happened again. I don't know if it makes a difference, but this time I made several stops along the way. After overnight at home, the error STILL has not cleared. May be time to contact Audi Service.