I had sort of the same problem. Wasn't getting updates and would not connect to wi-fi for probably a year or so. I got updates when at a SC and they pushed it through 3G. Had (supposedly) 2 replacement MCU's and problem persisted. Everything else worked other than no wi-fi or updates. They went through factory resets etc - still no good.
Eventually, they said my wi-fi connection from home, which was setup to connect automatically at home (it never did), was causing some sort of conflict and when it was deleted the wi-fi connectivity came back after Tesla service somewhere in the world fiddled with it remotely.
I don't know if what they were saying was true, or if knew what they were doing, or even replacing the original MCU (twice), but I didn't care about the details, and was happy that it was eventually fixed. I didn't care because it was under warranty at the time and I just kept on their case until thay resolved it. It also wasn't a huge deal that I didn't have wifi other than I had to get service to push through a 3g update. I only cared when they tried to charge me and I laughed pointing out it was a re-curring problem from the warranty period (by mileage, not time). All in all, they were trying their best but in reality probably didn't have much of a clue.
