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Wiki Consolidated eMMC Thread (MCU repair) (Black Center Screen)

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Its been a couple of years now since any of us cared about MCI1 failures - the frequencies. For a while we all did a lot of guessing. And simply to refresh new folks or folks that still have MCU1, I'd like to point you to an excellent article on eMMC/MCU1 failures. It does not report on every failure. But it breaks down by year with some interesting facts as to what was found.

And if you find yourself there, TeslaTap has done some great work on a wide variety of articles on all the Tesla models.
 
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Fun Fact is right, right on the money. I suspect there are a few here like me that can remember even before the first S was delivered. Tesla tried to call a meeting. Actually they did call a meeting, they invited VW, MB, Audi, BMW, Nissan, Toyota, Honda, GM, Ford to a EVSE Charging workshop. It was after the Roadster deliveries, but before the first S's were delivered. You know those days, it was when Tesla was more rumor than manufacturer. Tesla wanted a US standard and was of course was going to propose their S/X design plug/charge port. Same one we use today. I don't think we would have known this meeting was even called had it not been for a couple of EV e-mags reporting on it. It sort of embarrassed Tesla, but really pissed EM off. No one showed up to the meeting. The e-mags reported on the meeting and that no one attended by Tesla. Word was something like "if you don't want to go with our choice and don't want to discuss it, we will go our own way." Seems like a lifetime ago.

Hey and thanks for not calling out my mistake in that last post. The one where I fat fingered and said you had a X vice your S. Best of luck to you with your Porsche. I personally want all EVs all manufacturers to success with their own design & approaches. The more the merrier that reduces the ICE.
It's not a charging standard issue (though Tesla's is better, it's not the main issue here). It's Porsche supplier's bad design. Some more reading if interested.

TLDR; Porsche designed EVSE's based on pure theory, pushing the spec envelope to the point where unless you are plugging it in in an industrial spec installation, you will likely cause damage to your home. So they remedied it by halving the default charge current from 40A to 20A. You can override it, but only until next power cycle. Porsche did come up recently with a wall connector which is hard wired, avoiding a cheap supply cable issue, but that EVSE reportedly has problems charging non-Porsche EV's, even though it sports a standard SAE J1772 connector. Tesla actually sells a (SAE) J1772 Wall connector which is less than half the price of Porsche's but actually works for all EV's, including Porsche. I've actually recommended it recently to few non-Tesla owners, including my own family.

Another related thing: The in-car charging interface in a Taycan is one of the least intuitive of all EV's I've ever seen. It took me a while, and only after I started digging into the ISO15118 standard, did I realize that Porsche engineers essentially exposed the raw spec to the end user, rather than someone actually designing a typical user experience. It would like an app developer for a text editor, instead of putting a "Open", "Save" and "Save As" buttons, placed an "Open" button, then a dialog box with "read, write, append" choices, then a "Read" or "Write" button and then a "Close" button (which for non-programmers is a typical sequence of steps in programming to read or write a file) - it does the job, but completely unintuitive!

All that said, the car drives amazing! As much as love the P85DL Sport+ suspension, Taycan is a whole new league. Taycan also has things missing from Tesla, like proper brakes, much stronger regen (5x that of a Tesla), HUD, night vision, surround view, dynamic chassis leveling, rear axis steering, etc. I actually considered S Plaid, but overall, even though the Taycan is less powerful, has lower range and costs more money (with all the options I want, not available on Plaid), after considering all aspects I chose the Taycan Turbo. The yoke was probably the final straw for me. At that time I was making a decision, Tesla would not even allow any Plaid test drives, which means I never even tried it, but don't see myself liking it. I never bought a car on faith without test driving it, I guess I am not great Elon cult material. While I realize Taycan is far from perfect, neither is Tesla, and I'm looking forward to driving the Taycan soon. Only time will tell if I'm jumping out of the pan into a fire. 😂
Hey and thanks for not calling out my mistake in that last post. The one where I fat fingered and said you had a X vice your S.
For the purpose of this discussion, S or X is really irrelevant. 🤷‍♂️
Side note: I did originally have a Model X reservation, only to cancel it after test driving the first Model X - I simply did not like it compared to Model S. I was on my second Model S at that time, since I got bored of waiting for Model X.
 
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Hi @whitex, trying to answer your question, I’m not an authority on the matter, but if I remember well you get almost 5GB free out of 8GB in old fw versions (~2020), and I don’t think you would need more, unless video is stored in the MCU. But MCU1 does not store video, so you are good.

Also, the fw partition lives in RAM, you just store data (IMPORTANT data, like car certificates, etc) in the eMMC.
 
Just a quick update. I ended up doing the VCM recall. I figured I was already going in, and on the app itself I couldn't schedule this recall since the app said my emmc appeared healthy (no surprise there, the emmc I put in will outlive the car), therefore I figured the next owner would probably not be able to schedule it either, so I went for it.

Other than delaying my car by a better part of the day (apparently updating firmware takes a long time), it worked flawlessly. They even copied all the settings, security and homelink pairings! I was genuinely and pleasantly surprised. It's like they cloned the emmc from the old daughterboard to the new, so there was absolutely no re-setting up of anything afterwards. I honestly cannot even tell that they changed out the VCM (and no, I don't care enough to spend time taking my dashboard apart to confirm).
 
We have recently seen a Tegra board fail that was replaced by Tesla under recall. We are still looking into it but it appears the eMMC is fine and some other component has failed. It's likely a one-off issue, however Tesla has told him his "MCU has failed, and need to upgrade to MCU2 for over $2000, even after insisting they replace the board again. We have restored MCU functionality with replacement Tegra board "MCU Daughterboard" and looking into the failed board. Once again, we RARELY see MCU's fail, and if Tesla wont help we can most likely service the MCU.
 
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Hi @whitex, trying to answer your question, I’m not an authority on the matter, but if I remember well you get almost 5GB free out of 8GB in old fw versions (~2020), and I don’t think you would need more, unless video is stored in the MCU. But MCU1 does not store video, so you are good.

Also, the fw partition lives in RAM, you just store data (IMPORTANT data, like car certificates, etc) in the eMMC.
Actually, the firmware also lives on eMMC, in the P1 and 2 partitions. It is also loaded into RAM, however likely partially since the firmware can be up to 1 Gig, and it escapes my memory (pun intended) how much there is.
 
Can anyone tell me whether or not the latest MCU1 software requires greater than 8GB emmc storage space? I know that Tesla recall replaces them with 64GB, but does the software actually require it? What do you lose if you have an 8GB size?
You lose nothing at this point. Sorry if already answered. We are unfortunately not very caught up on this thread. Glad it still helps people. The extra space is simply used to wear level.
 
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You lose nothing at this point. Sorry if already answered. We are unfortunately not very caught up on this thread. Glad it still helps people. The extra space is simply used to wear level.
Yea, I ended up doing the VCM recall so the next owner won't have to worry it showing up as an outstanding recall. I noticed no differences in terms of MCU operation or responsiveness. 🤷‍♂️
 
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There seems to be a building of IC talk.... Yes the IC has a eMMC. we have seen a small amount of them wear out.... We are still looking for a good replacement chip and will start offering repairs if needed once we have a suitable chip.
When the MCU emmc's started to wear out, Tesla did a bunch of IC work to keep the wear down. To this day it annoys me that they actually shut down the IC overnight (didn't when I first bought the car), so if I want to drive it at 3 or 4 in the morning, I have to wait for it to cold boot (even if I preheat the car). Wakes up instantly during the day even if parked for few days (not sure what time they actually boot it up).
 
Actually, the firmware also lives on eMMC, in the P1 and 2 partitions. It is also loaded into RAM, however likely partially since the firmware can be up to 1 Gig, and it escapes my memory (pun intended) how much there is.
Yes, of course (otw upon reboot there wouldn’t be any os), but those blocks are only read, never written (unless you update). And yes, it’s about 1GB
 
Recently had the eMMC recall done proactively on the Tegra MCU in my 2017 S100D by Tesla Service

I got the vehicle back running old firmware. Took me 5 tries to update, but it eventually worked.
None of my settings where restored. I created a new profile and reconfigured most options.
Music streaming now just shows a slacker radio login screen. Use tesla account does not work.
The silver trim on the left side of the MCU is bowed out and not in proper alignment with the screen.
The widget on my android app no longer show proper battery status, but the app itself does.

They agreed to take it back today and address the issue.
 
what is the current price of the MCU2 upgrade for the 2016 model S?



This upgrade is available for $2,250 plus applicable tax, including installation, for vehicles equipped with Autopilot Computer 2.0 or 2.5 and for $1,750 plus applicable tax, including installation, for all other vehicles. Owners may confirm Autopilot Computer type by selecting ‘Controls’ > ‘Software’ > ‘Additional Vehicle Information’ on the touchscreen.
 
Recently had the eMMC recall done proactively on the Tegra MCU in my 2017 S100D by Tesla Service

I got the vehicle back running old firmware. Took me 5 tries to update, but it eventually worked.
None of my settings where restored. I created a new profile and reconfigured most options.
Music streaming now just shows a slacker radio login screen. Use tesla account does not work.
The silver trim on the left side of the MCU is bowed out and not in proper alignment with the screen.
The widget on my android app no longer show proper battery status, but the app itself does.

They agreed to take it back today and address the issue.
Nothing you pointed out is a surprise. Frankly, you should be pleased your settings were gone. Over 5+ years the car collects and retains residual out-of-date trash files that are no longer deleted or purged. Bringing those settings forward would include these files. You got a fresh start.

But don't depend on the firmware download/install issue to really get any better. That newer larger eMMC you got, is still old tech - just larger capacity. When you got the vehicle back was it running old firmware? That's a hint there's an issue. Previously, at the least, the tech would have downloaded freshest firmware, and it would be ready for install when you got home. Yours wasn't ready to install, hints that the tech didn't easily get it to download either.

MCU2 is 10X at least better than MCU1. And MCU2 is worth 2X-3X what they are charging. MCU2 is like getting a new '17 S.
Have you considered how lucky it is to be able to still get MCU2? Think about it. There's not a production model that is using MCU2. Why would the still be building them? Surely they are not making any decent margin on them. I often wonder how much longer its going to be available as an upgrade, before they disappear. THEN the real scramble begins,, eh? Finding a 3rd party fixer, that will/can swap out the junked used MCU2 we had to pay $5,000 for because they are rarer than hen's teeth.
 
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