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

[EV-Fixme]

Updated info about signals. It appears removing the negative from battery, which remove power to the whole car (Body Control Unit) will loose signal function. I confirmed signal is working with mcu removal, and will confirm later that removing the 12V power disables the signals.

 

[Akikiki]

When eMMC is starting to fail; do turn signals continue to work - although sound of turn signals ceased?

 

[TonyT]

When eMMC is starting to fail; do turn signals continue to work - although sound of turn signals ceased?

Yes they continue to work. However we would need to test if power is removed from a dead eMMC car if signal continues to work.

 

[dark cloud]

Updated info about signals. It appears removing the negative from battery, which remove power to the whole car (Body Control Unit) will loose signal function. I confirmed signal is working with mcu removal, and will confirm later that removing the 12V power disables the signals.

Maybe there is a connection between the signals not working and those who cannot charge their battery when the tegra board is vacant?

 

[Akikiki]

So you know why I was wondering. I've read a fair share of posts by owners, on TM and TMC, saying their turn signals stopped working. Nearly all these that I am referring to still have the MCU in the car. People asked more questions, like are they sure they are not working or just not making a sound. Most of the time, they post the are surprised to discover for themselves, the turn signals are in fact still working, just the sound was out.

When we started asking more questions, most of the time there's clues that the eMMC is failing. It appears that sound failing on S and X are often a subtle simple clue that the eMMC is starting to fail. That's my point. Not on all cars, but it seems that when sound stops its a hint of more to come.

What's your experience with this Tony?

 

[EV-Fixme]

Maybe there is a connection between the signals not working and those who cannot charge their battery when the tegra board is vacant?

I dont think the connection is the same. I had a car that could not charge prior to me removing the tegra. Also it could not charge after, and the 12 was not disconnected from car.

 

[EV-Fixme]

So you know why I was wondering. I've read a fair share of posts by owners, on TM and TMC, saying their turn signals stopped working. Nearly all these that I am referring to still have the MCU in the car. People asked more questions, like are they sure they are not working or just not making a sound. Most of the time, they post the are surprised to discover for themselves, the turn signals are in fact still working, just the sound was out.

When we started asking more questions, most of the time there's clues that the eMMC is failing. It appears that sound failing on S and X are often a subtle simple clue that the eMMC is starting to fail. That's my point. Not on all cars, but it seems that when sound stops its a hint of more to come.

What's your experience with this Tony?

Correct, no sound is a symptom. I have never seen a car that failed to light signal with emmc failed. I've only seen small reports of signal not lighting, and experience for my first time on 1 car I removed emmc as preventive. This car was also having charger replace and slave added. Due to that I disconnect HV and 12V, and found the signal would not work.

 

[Akikiki]

Maybe there is a connection between the signals not working and those who cannot charge their battery when the tegra board is vacant?

Tony is going to jump in and correct me if I say something wrong here. And I depend on him to do that. I believe that those cars that can not charge as the eMMC is failing had Scheduled Charging set. Does not matter when, its the fact that Schedule charging was set. And I guess the next logical step is to believe its going to be able to charge after the eMMC is removed. But, I think not. From reading accounts when the eMMC was removed or failed (there's not a lot of these reports/posts) I think the car still remembers Schedule Charging was set. And since it lost or can't recognize its location/time or maybe both, it does not know when or that you are trying to charge. So it skips its charge and will not start manually. Most of the time the car and app have stopped communicating too. Can't start charging from the app.

As I recall, I think it was Tony that warned people that if they think that their MCU/eMMC is failing, that it would be wise to turn off Scheduled Charging as a precaution. Why would this matter? If your MCU/eMMC is failing or failed and you are waiting for your SC appointment or 3rd party appointment you don't want your HV battery to run down to far that you can't get it in to the shop. If Scheduled Charging is set, you can't keep your car charged.

 

[Barry]

I was told by a service tech when my car was in that if there are warning signs, turn off PIN to drive, too, as there will be no way to enter the PIN when the screen goes dark.

 

[Akikiki]

YES !!. I knew there was something else that "we" should do. Thanks, Barry.

 

[whitex]

@EV-Fixme, a couple of question (sorry if they have been covered before, I didn't see the answers):

1. Is the battery BMS able to control temperature of the battery while the MCU is out? What about if one was to disconnect both HV only or both HV and 12V - would that put the battery into some hibrenation self-sustaining mode?
2. You recommend using a battery tender, will that have any issues with HV battery trying to top off the 12V battery at the same time? Or should HV emergency loop be removed, and if so, any issues with battery being able to cool/heat itself?

 

[dark cloud]

So you know why I was wondering. I've read a fair share of posts by owners, on TM and TMC, saying their turn signals stopped working. Nearly all these that I am referring to still have the MCU in the car. People asked more questions, like are they sure they are not working or just not making a sound. Most of the time, they post the are surprised to discover for themselves, the turn signals are in fact still working, just the sound was out.

I can confirm the signals did not emit light at all. I never did disconnect the 12v either, but the battery did discharge enough for the car to deem it “dead”, so essentially I suppose that is the same thing.

Tony is going to jump in and correct me if I say something wrong here. And I depend on him to do that. I believe that those cars that can not charge as the eMMC is failing had Scheduled Charging set. Does not matter when, its the fact that Schedule charging was set. And I guess the next logical step is to believe its going to be able to charge after the eMMC is removed. But, I think not. From reading accounts when the eMMC was removed or failed (there's not a lot of these reports/posts) I think the car still remembers Schedule Charging was set. And since it lost or can't recognize its location/time or maybe both, it does not know when or that you are trying to charge. So it skips its charge and will not start manually. Most of the time the car and app have stopped communicating too. Can't start charging from the app.

My eMMC never failed, I changed it before it did, and as I planned to change it I definitely removed scheduled charging ( and pin) and I was charge limited.

look at my post a few pages back; the charge level was set at 75% but it said charging complete; on supercharger it said “limit not set high enough” or something like that.

if we just have one person confirm they removed scheduled charging and they could charge up to the set level before Tegra removal then that theory is false. I’m pretty sure there are many.

 

[Akikiki]

dark cloud you are right. Breaking the specifics of this will help everyone understand. There's a scenario that we need to pay attention to. Tesla doesn't do it, but some 3rd party fixers are. That where the eMMC has failed, and the Tegra board is removed (maybe sent to a fixer, and the owner puts the MCU back in without the Tegra board and drives the car while waiting to get the board back. So there's preparation before, and how those settings affect the car while the Tegra board is out - the MCU is black/blank..

 

[amiral_sub]

Hi, 2 months ago my emmc was changed by a swissbit. Everything worked fine. Since yesterday I have big troubles with the MCU. This week I received an update 2020.8.2, I installed it. Yesterday I drove the car, spotify did not work at all, I rebooted the mcu. It took a very long time to reboot (maybe 10min). Then it did not work well: unable to connect bluetooth, big display problems, no communication anymore with the app.
I tried to reboot, it is now black.
I pulled off the fuse, put it back. The mcu is always black.
The dashboard displays that I don't have anymore parksensors. It don't have anymore rampage. It is like my mcu is dead
What can I do ?

 

[T.R.T.e.s.l.a.]

Hi, 2 months ago my emmc was changed by a swissbit. Everything worked fine. Since yesterday I have big troubles with the MCU. This week I received an update 2020.8.2, I installed it. Yesterday I drove the car, spotify did not work at all, I rebooted the mcu. It took a very long time to reboot (maybe 10min). Then it did not work well: unable to connect bluetooth, big display problems, no communication anymore with the app.
I tried to reboot, it is now black.
I pulled off the fuse, put it back. The mcu is always black.
The dashboard displays that I don't have anymore parksensors. It don't have anymore rampage. It is like my mcu is dead
What can I do ?

Have you already contacted the person who replaced the emmc for you?

 

[GlmnAlyAirCar]

I believe that those cars that can not charge as the eMMC is failing had Scheduled Charging set. Does not matter when, its the fact that Schedule charging was set.

I was one of those whose car wouldn't charge. And I did not have scheduled charging set prior to disconnecting the MCU. To be more specific, I could charge up to 21%, but at a very, very, very slow rate (1 mile every several hours). But it would not charge at all beyond 21%. Something else was going on here.

 

[dZeiS]

My MCU was failed and eMMC changed. However, the vpn credentials were not survived so now I have a car without 3G, App connection etc.

Does anybody know if I still can Supercharge or not? I have Unlimited Free Supercharging in my car.

 

[Banjo]

My MCU was failed and eMMC changed. However, the vpn credentials were not survived so now I have a car without 3G, App connection etc.

Does anybody know if I still can Supercharge or not? I have Unlimited Free Supercharging in my car.

I was able to in the US. Also, you should have 3G connectivity, even without VPN app connection. Who did your eMMC swap?

 

[Akikiki]

My MCU was failed and eMMC changed. However, the vpn credentials were not survived so now I have a car without 3G, App connection etc.

Does anybody know if I still can Supercharge or not? I have Unlimited Free Supercharging in my car.

Its unlikely you will be able to Supercharge. I hope for your sake that I am wrong. But its those security certificates that identifies your car and authorizes it to complete the handshake with the Supercharger system. Whatever you find out after your next Supercharger attempt, we would like to know. Please report it here.

 

[Banjo]

Its unlikely you will be able to Supercharge. I hope for your sake that I am wrong. But its those security certificates that identifies your car and authorizes it to complete the handshake with the Supercharger system. Whatever you find out after your next Supercharger attempt, we would like to know. Please report it here.

I was absolutely able to Supercharge without certificates, in the US. YMMV