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Likely MCU Failure (MCU1 eMMC)

Problem is, since I don't have screen access, I can't turn the power off and I'm getting sparks when attempting to disconnect the battery.
Always remove the negative side first. That way you have no concerns about touching a wrench to anything during the process. I have heard one other member who ended up having his brand new car with a very loose battery terminal and the car was not working correctly and kept having issues.
myself personally I would get to the negative side disconnect for a minute or two. Reconnect and make sure the plus side is snug and not loose. If none of that yields anything. Time for the SC in my book.
 

scaesare

Well-Known Member
Mar 14, 2013
8,810
16,254
NoVA
Have the limitations on the vehicle associated with an MCU1 failure been summarized? I believe the following are true...

No charging
No main display
No HVAC controls
No audio controls

And my specific question, similar to the loss of HVAC controls - does the battery cooling system still operate? During summer months, the vehicle cooling the battery in the afternoon is a common occurrence for my vehicle; losing that would presumably be not good.
One note: If you lose 12v supply, you also lose the ability to reauthorize via the fob, and with the failed MCU using the app to drive doesn't work. This makes the car immobile.
 

scaesare

Well-Known Member
Mar 14, 2013
8,810
16,254
NoVA
Problem is, since I don't have screen access, I can't turn the power off and I'm getting sparks when attempting to disconnect the battery.
Sparks when removing the 12v terminal is normal. Renege to pull the HV disconnect loop to make sure the DC-DC is not supplying power.

Alternatively you can just pull the MCU fuse if you are trying to do a hard reboot.
 

scaesare

Well-Known Member
Mar 14, 2013
8,810
16,254
NoVA
What fuse # is it?
The fuses (and fuse box locations), have moved around a bit, but if you have an early MCU1 car like mine, it's F51 circled here:

FuseLocation.PNG
 
I have a 2019 MX that I bought about a month ago as a demo with ~1400 miles on it. As of this morning, both screens are black and the car has lost connectivity via the app, so Tesla can't remotely troubleshoot. I can drive the car, but without instruments. Seems like an MCU issue, possibly MMC caused.

Has anyone seen this happen on this new of a car? Or any other ways to reset the MCU?

End result was I couldn't get it back in (or even in gear as of this morning). Tesla sent a tow truck, which had to drag it out of my garage and onto the flatbed. We'll see what happens from here.
 
Do you have a invoice indicating this price. I'm going in tomorrow to have my dead eMMC/MCU replaced. That price sounds way better than the $2800 I've seen on other posts.

EDIT: I was just quoted $2952. Does anyone have proof of a less expensive repair?
View attachment 469307
It looks like they're giving you a brand new MCU; the cheaper price comes with them installing a refurbished MCU, though we have no idea how the units are actually rebuilt. Some may argue that a brand new MCU may be better since the memory chips will be virgin...
 
So I have been working with @TonyT to get the files off of my eMMC. Unfortunately he was unable to get the files off and I had to get Tesla to install a new MCU. Tesla service center of Orlando's stance on MCU replacements is that you get to keep the MCU if you pay for it out of warranty. If it is a warranty replacement you have to pay a core charge. My total with a refurbished MCU was $2,100 with also allowing me to keep my old MCU. They also may have given me a single hour labor rate due to bringing the car in with the dash already apart.

If anyone is thinking about trying to recover the files off of the eMMC before it goes bad, reach out to Tony, he has been great to work with and provides constant updates!
MCU replacement.JPG
 
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Just wondering, would it be possible to install a new emmc chip either blank or with the software you a re able to get out of it, and then drive down to Tesla and have them reinstall the software on the repaired MCU?

I guess, that when Tesla installs a "new" MCU it will be with the same type of emmc that will wear out in a few years as well and you will have to pay them 2100 usd every 2-3 years...
 
Just wondering, would it be possible to install a new emmc chip either blank or with the software you a re able to get out of it, and then drive down to Tesla and have them reinstall the software on the repaired MCU?

I guess, that when Tesla installs a "new" MCU it will be with the same type of emmc that will wear out in a few years as well and you will have to pay them 2100 usd every 2-3 years...

So the new installed MCU is supposed to have a 4 year warranty on the parts but I'll update if they say something different. I am also expecting to get LTE for free as part of the upgrade and the screen is one that supposedly doesn't bubble or yellow.

But in addition to that I am working with Tony to have a working eMMC without logging enabled but without the VPN/etc certificates installed on it. It should allow me to use the car without the app until he is able to pull the files off of the new eMMC that I will be shipping to him once I have the new MCU in my hands.
 

StarLog

Member
Supporting Member
Mar 11, 2019
458
210
MCO
@FPLPowered ,

So your car is still at ORL, how long will it be there for this.
Also, they did or did not charge you for the old MCU, after you paid the $2092.99
I thought any equipment that was out of warranty was always yours to keep no charges. Thought that was a law in FLA.
Also, you took most of the dash off, so they only charged you an hour that true.?

Thanks
 

MP3Mike

Well-Known Member
Feb 1, 2016
19,422
48,270
Oregon
Also, they did or did not charge you for the old MCU, after you paid the $2092.99
I thought any equipment that was out of warranty was always yours to keep no charges. Thought that was a law in FLA.

Unless there is a core charge. (Or core refund depending on if they include the core charge in the price of the part.)

Technically they shouldn't give you the old part back at all, even with a core charge, for a warranty repair. But Tesla is new at this and is still learning.
 
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@FPLPowered ,

So your car is still at ORL, how long will it be there for this.
Also, they did or did not charge you for the old MCU, after you paid the $2092.99
I thought any equipment that was out of warranty was always yours to keep no charges. Thought that was a law in FLA.
Also, you took most of the dash off, so they only charged you an hour that true.?

Thanks

They had the MCU onhand and stated that it should be done within 24-48 hours. They also provided me with a Model S loaner which I haven't gotten at the Orlando service center in awhile. I dropped it off this morning.

They did not charge me for the old MCU. It was $2092.99 (labor might change) and I keep the old MCU. I actually did not know of that law in Florida but good to know.

I saw on another quote for a MCU replacement from another TMC member here that they were quoted for two hours of labor for about $250. I brought up that I had the whole dash apart for them and the MCU was easily accessible and asked if they really needed two hours of labor. The guy I was working with agreed with me and is charging me for a single hour and in my quote it is looking like $140 for labor. It is a quote so I guess technically it could change but at least they agreed that I should get a break for already taking the dash apart.
 
They had the MCU onhand and stated that it should be done within 24-48 hours. They also provided me with a Model S loaner which I haven't gotten at the Orlando service center in awhile. I dropped it off this morning.

They did not charge me for the old MCU. It was $2092.99 (labor might change) and I keep the old MCU. I actually did not know of that law in Florida but good to know.

I saw on another quote for a MCU replacement from another TMC member here that they were quoted for two hours of labor for about $250. I brought up that I had the whole dash apart for them and the MCU was easily accessible and asked if they really needed two hours of labor. The guy I was working with agreed with me and is charging me for a single hour and in my quote it is looking like $140 for labor. It is a quote so I guess technically it could change but at least they agreed that I should get a break for already taking the dash apart.
This is about the same experience I had on friday (3 days ago) I kept the old unit. Car is no longer covered under warranty.
Screen Shot 2019-10-28 at 3.27.58 PM.png
 

Congo Line

(not the dance)
Feb 2, 2013
176
1,141
East Coast
Just out of curiosity, do you have anything plugged into any of the USB ports, such as a memory stick? If you do, remove the memory stick and then try rebooting the MCU.
The only reason I mention that is that my own car had similar behavior and the service center diagnosed it as a fault in the memory stick or a corrupted file on it. Odds are, your case is different, but mentioning it "just in case...."

That's interesting; my MCU was acting up recently after a new software download (kept rebooting over and over). Coincidentally, I had recently plugged in a USB stick with some music files on it, but had never thought of the possibility that it was related. The software eventually did start working properly after I got another version which came out within a short interval of time. But by then I had unplugged the USB stick too.
 
Just wondering, would it be possible to install a new emmc chip either blank or with the software you a re able to get out of it, and then drive down to Tesla and have them reinstall the software on the repaired MCU?

I guess, that when Tesla installs a "new" MCU it will be with the same type of emmc that will wear out in a few years as well and you will have to pay them 2100 usd every 2-3 years...

No Tesla will not restore a car with a "blank emmc" and I would doubt the SC will have the ability to restore from that level. I would imagine you would need to have a stellar relationship with the SC who would probably need engineering to assist in this type of restoration. The MCU you would buy from Tesla SC would be in a ready to install into car state. This would really require the stars to align for you to have this done.
 
They had the MCU onhand and stated that it should be done within 24-48 hours. They also provided me with a Model S loaner which I haven't gotten at the Orlando service center in awhile. I dropped it off this morning.

They did not charge me for the old MCU. It was $2092.99 (labor might change) and I keep the old MCU. I actually did not know of that law in Florida but good to know.

I saw on another quote for a MCU replacement from another TMC member here that they were quoted for two hours of labor for about $250. I brought up that I had the whole dash apart for them and the MCU was easily accessible and asked if they really needed two hours of labor. The guy I was working with agreed with me and is charging me for a single hour and in my quote it is looking like $140 for labor. It is a quote so I guess technically it could change but at least they agreed that I should get a break for already taking the dash apart.


Thanks for the kind words!. For sure anyone seeing signs of problems that are not a external usb stick related, contact us or some of the members here that can attempt a recovery service. Time is not on your side when the eMMC is showing signs of failure. If your MCU is 3-5 years old it would be a great idea to consider this swap unless Tesla starts to decide offer "goodwill/recall" replacements.
 
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So the new installed MCU is supposed to have a 4 year warranty on the parts but I'll update if they say something different. I am also expecting to get LTE for free as part of the upgrade and the screen is one that supposedly doesn't bubble or yellow.

But in addition to that I am working with Tony to have a working eMMC without logging enabled but without the VPN/etc certificates installed on it. It should allow me to use the car without the app until he is able to pull the files off of the new eMMC that I will be shipping to him once I have the new MCU in my hands.

FPLPowered is very Pro with his car! We are working out some new processes. Anyone looking to work with us remotely please make sure to contact me before working on your car at all. I'm writing up a process so owners don't damage any parts of their car such as Windows, Battery, Dash (always a risk of damaging the aluminum trim.
 

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