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MCU failed after 36k miles

Grant

Member
Mar 22, 2015
35
47
Virginia
I knew this was an issue but was surprised that the MCU failed so soon. I have a 2015 90D that I bought from Tesla in 2018 so it is still under warranty. 36,400 miles. I had a few issues in January/February where the center screen spontaneously turned off for 1-2 minutes while driving. I also had a jumbled display when pulling up the HVAC once. I haven't driven a lot since then but I did notice that for about two weeks before the MCU died, a new software update (2020.12.5) would not install. It would go to 10% and stop. I didn't think too much about it.

Here is what happened when the MCU died for good. Car was technically driveable but:
-Center screen was completely off (screen above steering wheel still on)
-Odometer showed ----
-Temperature showed --
-Parking sensors did not work
-Turn signals did not work (but emergency blinkers still worked)
-Phone app not connecting
-Soft and hard reboot attempts had no effect

I brought the car in this week and they put in a remanufactured unit (part number 1098010-00-G). I did speak to someone in the service department and asked if this one they are putting in is going to fail again because of the memory defect and he said it's been "corrected" (via a software fix). Can anyone confirm this (that the logging issue that eventually causes the eMMC memory failure been fixed/improved)? Or is this going to crap out again in 4 years? Does anyone know if they start with a new eMMC memory chip on the remanufactured units?

MCU part number.PNG
 
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ucmndd

Well-Known Member
Mar 10, 2016
6,909
13,050
California
It has been mitigated insofar as the amount of logging to the chip has been reduced in recent releases, but calling that "fixed" is probably a bridge too far. Eventually it will happen again.
 
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sorka

Well-Known Member
Feb 28, 2015
8,242
6,014
Merced, CA
The logging fix that reduces the logging went in years ago, so your MCU failed in 36 months while already having the fix they told you about.
 

ucmndd

Well-Known Member
Mar 10, 2016
6,909
13,050
California
The logging fix that reduces the logging went in years ago, so your MCU failed in 36 months while already having the fix they told you about.
I believe they claimed fixes years ago, but @wk057 confirmed as recently as October of last year that they were still flogging the chip pretty hard. Apparently there was some actual improvement shortly after that.
 

Altes

Member
Sep 30, 2016
637
486
SF Bay area
Yeah, i would say its a pretty big fail except it was intentional, there was no "logging fix" unless you mean logging MORE data. A significant portion of Teslas worth will be the data they gather on self driving so it behooves them to log as much as possible. they only realized this after committing to a memory hardware architecture but are logging just enough to be out of warranty when the unit fails. in some instances they miss, my car was JUST out of warranty so I had to pony up the 2000 for a REMANUFACTURED MCU. they refused the MCU-2 upgrade as they are too overwhelmed with cars they had not planned on servicing at all and had never planned on in there service center infrastructure model.
 

Akikiki

A'-Lo-HA ! y'all
Nov 26, 2012
6,476
4,558
Kaneohe, HI
@Grant, Answer to your question: Yes, its going to happen again. Its 2010 tech and they put the same size chip back in the car. Yes, its a new chip, it has to be, but setup the same way as before. The car will behave - at first like it did if it was brand new, meaning. MCU response time will be great and things will work. But just like a Windows computer will slowly but surely begin to slow down and needs the OS to be reinstalled, the same happens to MCU1.

Logging is not the only "bad practice" that the car does that impacts the MCU/eMMC. Reducing logging helped, but did not eliminate what is believed to be some of the other damage. One of the other things that we have been told causes problems for the eMMC is using large thumb drives with excessive amount of music/ data (MCU has to parse all that data for indexing) The larger the drive capacity of music, the more indexing. And each time the flash drive is removed/reinserted, the process of indexing begins again.

MCU2 is a 4X larger chip. Performance is wonderful. Mine has been upgraded to MCU2 and it seems like a new car - it is not a new car. If you can upgrade to MCU2 when offered, I highly recommend it.

You are lucky that yours is still under warranty. Saved you about $1600.00.

What is the build date of your car? Build date is on the sticker on the driver side door opening.
 
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Grant

Member
Mar 22, 2015
35
47
Virginia
What is the build date of your car? Build date is on the sticker on the driver side door opening.

The build date is 9/15.

I have only had the car back for a day but I noticed that the music panel is not opening at all (just the loading animation). Anybody have any idea what could be causing that? I now have version 2020.12.11.5 software running.
 

Grant

Member
Mar 22, 2015
35
47
Virginia
Did you talk to them about getting MCU2? I am hoping that when mine fails, they'll offer me MCU2 at a discount since my MCU1 is still under warranty.

I did not ask and they did not offer. Isn't that a $2k upgrade? I'm unclear on the benefits that would have for my AP1 car.
 

IslandHydro

Member
Oct 24, 2018
215
132
Washington State
I did not ask and they did not offer. Isn't that a $2k upgrade? I'm unclear on the benefits that would have for my AP1 car.
Yes it is 2K, I'm hoping it might be substantially less if they are on the hook for fixing my AP1. Theoretical advantages are reliability, speed, and a working web browser.
 

Akikiki

A'-Lo-HA ! y'all
Nov 26, 2012
6,476
4,558
Kaneohe, HI
@IslandHydro, If they let you do that - in the near future, you would be the first reported that they allowed to do that. People have already tried.

@Grant, The upgrade is $2500, not $2,000 and you would lose AM/FM-FM/XM radio too. Many of the benefits that we see on an AP2 car would not be realized by a '15 car. But you would see improved maps, faster NAV, browser works. LTE, but you already are. Really would be questionable benefit for you, except if you needed another eMMC replacement, - in that case it would be better.
 
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croman

Active Member
Nov 21, 2016
4,912
7,143
Chicago, IL
My MCU1 failed and it was under warranty and I did try for MCU2 and Tesla was unable to do it and I got a new MCU1. Actually it works great and am trying to just get HW3 and not updating just yet.
 

dragoljub

Member
Feb 16, 2017
353
596
Los Altos, CA
Like Croman, I had the same issue. 33.5k mikes MCU1 died. I had FSD pre paid for so I was able to pay for MCU2 upgrade and got FSD upgraded while they did MCU. I would have not upgraded MCU if mine was not dead.
 
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IndyToronto

Member
Nov 14, 2019
74
42
Toronto, Canada
Mine started failing occasionally at just under 30k miles, got significantly worse at 31kmiles (corrupted icons, daily audio hangs).

MCU went completely dark and stayed dark at 33k miles last week. Was replaced in SC dropped off 72 hours ago and got the car back yesterday.

2016 MS 70D.
 

Hahamhadoor

New Member
Jun 10, 2018
3
2
New Jersey
Mine went in February, SC cleared memory and revived chip, told me if it acts up again they will replace MCU. The fix lasted 4 weeks, center screen dead, car still runs, no radio, signals, HVAC, defogger, seat settings, bluetooth, or app connection. SC claims that due to COVID the distribution center is unable to ship refurb model. Every appointment has been cancelled and rescheduled since March. Next appointment June 17. We shall see. 2015 85D, October 2015 build, 71,000 miles. Still under extended warranty
 
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CaliMS

Member
Oct 8, 2017
143
99
CA
Rookie question here..... the warranty on the MCU when you buy new is? 4 years? (looks like that on the site, but I know these things have changed over time).
 

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