Turn signal function lost

[CFinVancouver]

My 2015 model S 85D with 75000km started to experience MCU issues on Saturday, traveling from Calgary back to Vancouver. The screen during an overnight charge would not start up in the morning. Center screen was still functioning, and Roadside service said it would be drivable. We managed without AC and navigation, until an hour later when the screen came back up. Stayed working and I stayed with the car during supercharging so it did not go to sleep.
Crazy thing, NO TURN SIGNAL FUNCTION!
Hazard lights worked. No indication turn signals were working on center screen, so we got out in a parking lot and visually checked. Nothing.
Appointment this week to have this sorted out.
Yes, tried all the resets.

 

[mrElbe]

Are you by any chance on firmware update 2020.20.1 ? This update has major problems. On the other hand, it might be the infamous MCU issue. Be prepared for a hefty quote to fix it.

 

[CFinVancouver]

Yes I have 2020.20.1
Seems to be working fine today, I have 4 hours of driving to get us home.
I am hoping some data clearing might get me a few more months...

 

[CFinVancouver]

Reported issue to Transport Canada. Tesla claims the turn signal will work when MCU 1 is down, yet my repeated experience is to the contrary.

 

[CFinVancouver]

My 2015 model S is sitting in the my garage with intermittent function and no turn signals when down.
Appointment tomorrow with Tesla, texted me options...new MCU2 3775 CDN + tax, or refurb MCU 2600cdn +tax (6 week wait).
I have a day to decide, any thoughts?
I do not need Netflix or a faster browser, just something that will last me the life of the car.

 

[CFinVancouver]

It is done. Went from failed MCU1 AP1 in 2015 Model S 85D. Vancouver shop is very busy, it took a day and a half. It appears the new unit came with a new screen, trim was recycled.
Because of the limited features for my car, I would have not chosen to go to MCU2 for the price, I added Netflix, a faster browser (not laptop fast)and LTE. Another person was also having an MCU replacement while I was collecting the car. Judging by the sheer fact the service centre had an MCU2 in stock, this is an emerging scenario.
I am really disappointed that the Roadside people assured me the car was functional if the centre screen was working (ie no turn signals).
I think there are a whole host of tell-tale signs leading up to the failure...slow map refresh, sporatic Wifi connectivity. These had been evident for awhile. The blank screen and very unpredictable startup seemed to be all of a sudden in my case. Likely people will experience some of the same common signs and other will have unique deficiencies as the MCU dies. Still I really enjoy the car.
I find the whole service experience is just like a traditional dealership, the intake guy has no idea what is going on...need a loaner? Are you sure it is the MCU? let me go find a technician. I just kept telling him read the note/email. At least somebody would text and answer my questions ov er the course of a day and a half.
PS. the loaner was an older P85 with a single motor...the regen is much less than a two motor car like mine, almost as much as switching mine down a level. Many thanks for all the guidance.