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Tesla now repairing MCU1 with a new Tegra card for less than $500

zwede

2013 P85+
Jan 17, 2014
637
337
Plano, TX
@zwede , it's the issue from the other thread:
Consolidated eMMC Thread (MCU repair) (Black Center Screen)

It must have been a surprise to Tesla as well, that the board swap doesn't work with all cars. There seem to be many owners now with GPS or audio problems..

Aha, Thanks. I figured I couldn't have been the first to run into this. You'd think Tesla would offer a newer MCU1 for the same price as Tegra replacement to support us early adopters...
 

whitex

Well-Known Member
Sep 30, 2015
6,789
8,624
Seattle area, WA

reddy

Active Member
Jan 26, 2013
1,012
1,599
Amarillo, TX
Update 1: Got text that my MCU is too old to be compatible for Tegra swap???? Wtf?

Update 2: So apparently early cars can't use the Tegra replacement board. Mine is built July 2013. VIN in the mid-15K range.

Yep. Fiasco.

My car is older than yours, and they sent a Ranger to my house to replace the Tegra daughterboard. After the daughterboard replacement the center touchscreen wouldn't illuminate. The poor guy struggled with it for 4 hours before giving up and telling me that the Tesla people back at home base were remoting into it to update firmware, which would fix the problem.

They eventually gave up too, and decided to replace the full MCU. A Ranger returned today and successfully replaced the full MCU along with a new touchscreen. All is back to normal, but it took 11 weeks to go through the entire fiasco! 11 weeks !!

It's nice to have my car back though, with working AC, turn signals, and radio.
 

Zuikkis

Member
Aug 19, 2020
268
321
Finland
.

Do you mean to suggest that Tesla doesn't test their designs - as long as the solution worked on one engineer's desk or car, they ship it, and then are surprised if it doesn't work for all cars? :eek:

To my understanding, Tesla buys the MCU from outside the company. Tegra daughterboard didn't even have it's own part number until very recently, they just replaced the whole MCU as single part. It's possible the subcontractor has changed MCU design during the years without telling Tesla, because the whole MCU device still has identical function.

Anyway it seems that Tesla is now aware of the situation and doesn't offer daughterboard replacement for older cars.
 

whitex

Well-Known Member
Sep 30, 2015
6,789
8,624
Seattle area, WA
To my understanding, Tesla buys the MCU from outside the company. Tegra daughterboard didn't even have it's own part number until very recently, they just replaced the whole MCU as single part.
I don't think that's the case - Tesla designed that MCU, including modifying (or requesting someone to modify) the Nvidia VCM module (there is still an Nvidia logo on the Tegra board itself). Tesla has had separate replacement part numbers for the MCU screens for a while (and those work in MCU1 and MCU2, the latter not having an Nvidia board in it), so MCU was never really a single part number. Thee fact that they didn't let SC's order the Tegra board before does not mean they didn't have a part number for it in manufacturing.

It's possible the subcontractor has changed MCU design during the years without telling Tesla, because the whole MCU device still has identical function.
Not possible with automotive companies and their strict processes, where any such change would have to be reviewed and approved by the manufacturer. Extremely unlikely for Tesla, which doesn't have such strict processes, however does have a control freak in charge who insists on extreme vertical integration.
 
Last edited:

jjhoov

Member
Mar 21, 2019
21
33
Delaware, OH
I have a 2015 S85D, my MCU failed about 3 weeks ago right before I left for a work trip.

It previously stopped responding about a month and a half ago, for 2 days it did nothing, had no HVAC etc. Miraculously on the drive home from a work trip, 5 minutes from home after 9.5 hours driving, it decided to come back alive. I took it to the service center, they said an update had failed to apply and was had corrupt files. They did their software fix and it worked for a few weeks.

About 3 weeks ago my MCU rebooted while i was driving and never came back alive again. Service appointment set up, and they confirmed likely it was dead, as the HVAC stayed on in the last state (AC which worked perfect bc it was hot). I left for a work trip and dropped car off Tuesday, they had ordered the daughterboard and it was there. Got a loaner car, as the advisor I normally work with said the daughterboard installs either go really quick and they're done in a few hours, or they take a day or two.

Received call car was ready, went and picked up, and it's night and day difference even staying MCU1. i'm noticing mapping updates and nav tracking are going much smoother, in general all around it feels better. All covered under my Used 4y50k warranty.
 

CliffG

Member
Feb 10, 2014
312
89
New Jersey
To my understanding, Tesla buys the MCU from outside the company. Tegra daughterboard didn't even have it's own part number until very recently, they just replaced the whole MCU as single part. It's possible the subcontractor has changed MCU design during the years without telling Tesla, because the whole MCU device still has identical function.

Anyway it seems that Tesla is now aware of the situation and doesn't offer daughterboard replacement for older cars.
Bah.

So now the question (for those of us who have not followed closely) is: do the replacement MCU's for older Models S come with the old daughterboard?
 

Uxorious

Member
Oct 2, 2019
10
23
San Francisco, CA
(Copied from another thread)

So mine died a month ago.
I had 2 weeks left in the 4 year warranty, but I was at 60k miles, so they said it was not covered.
Advisor quoted me the roughly $1500 for a remanufactured MCU1, or $2500 for MCU2 (which loses the radio).
I told him (nicely) that this was unacceptable since it's a manufacturing defect, and that they are even being investigated for it.
After this he said they could also try replacing the MCU1 (the Tegra daughterboard mentioned here). This would be around $350 ($120 for the daughterboard, the rest labor) - but he wasn't sure how long it would be to get.
Since I don't need the car these days I told him I could wait.
1.5-2 weeks later the daughterboard came in ... but the repair didn't work.
Another advisor called me back and said it didn't work, so back to the original $1500-$2500 options.
I called the first advisor back, and he told me he had already ordered a remanufactured MCU1 (at their expense), and that they would swap the "frame" of that into my vehicle.
Took 1.5-2 weeks for the new part to arrive.

So in the end (after almost a month), I have the car back with a 64 GB remanufactured MCU1 at a total cost of $350.

Find a service advisor who is willing to go to bat for you!
 

Gt1948

2017 S FSD AP 3.0 MCU 1
Aug 17, 2017
234
124
Millington TN
My car is older than yours, and they sent a Ranger to my house to replace the Tegra daughterboard. After the daughterboard replacement the center touchscreen wouldn't illuminate. The poor guy struggled with it for 4 hours before giving up and telling me that the Tesla people back at home base were remoting into it to update firmware, which would fix the problem.

They eventually gave up too, and decided to replace the full MCU. A Ranger returned today and successfully replaced the full MCU along with a new touchscreen. All is back to normal, but it took 11 weeks to go through the entire fiasco! 11 weeks !!

It's nice to have my car back though, with working AC, turn signals, and radio.
So is the new MCU 1 or 2?
 

Dale Hoppas

Member
Apr 8, 2018
8
2
Port St Lucie,
I have 2018 model S 100D, with almost 100,000 miles, The MCU1 is slow and starting to blackout or reboot during driving now. It seem that some updates started this mess. Its like they send out updates to out-date items they cannot control or want you to replace.
Sooner or later I will have to pay to change to the MCU2.
I plan on keeping this car long term, its still fun to drive.
Dale
 
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cicob

Member
Apr 1, 2018
8
3
Zurich
I have 2018 model S 100D, with almost 100,000 miles, The MCU1 is slow and starting to blackout or reboot during driving now. It seem that some updates started this mess. Its like they send out updates to out-date items they cannot control or want you to replace.
Sooner or later I will have to pay to change to the MCU2.
I plan on keeping this car long term, its still fun to drive.
Dale

I'm with you on this one. All Model S/X produced as of March 2018 have MCU2. Mine was out the door in Feb 2018...

At times, lowering the volume on the radio takes 15-20s before it's executed. Sooo ridiculous to see on a car in this price-range. People would have been fired if this would ever have happened on a Beemer or Merc. Period.

This great video says it all (trying to cross-link here... unsure if it works):
Tesla confirms infotainment system upgradeability from MCU1 to MCU2 for $2500

Direct youtube-link:
 
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