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MCU Flash Memory Wear?

100KWH

Member
Aug 20, 2018
77
18
Sydney
An interesting read: UPDATE: Tesla Cars Have A Memory Problem That May Cost You A Lot To Repair

Has anyone experienced this? My car's a late-2017 MY (Feb-2018 delivery) P100D Model S though I've only driven it 22,000km or so, and thus I don't expect it to happen any time soon. That said, the article does claim that late-2017/early-2018 MY cars could be more prone to this (and it's MCU1, no less).

If true, it's a bit crappy that a mere eMMC chip can render the whole MCU useless, but that said I wouldn't mind getting a MCU1->MCU2 upgrade out of it this. Perversely, I might actually want the flash to wear out while the car's still under warranty...
 
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Brian May

Member
Apr 9, 2016
284
64
Melbourne
The article says things like "If your car was made before 2018 and is still under warranty, try to verify if your MCU is working properly." which I have no idea what it means.

Plus it says "Tesla CEO Elon Musk thinks this should be much less of a problem now. Check out the embedded tweet below:" - what embedded tweet? I can't find it.
 

rohan3au

Member
Oct 27, 2017
367
639
Newcastle, Australia
According to the first article other thread, the car is still drivable, but functions such as defroster won't work.
But if you have Pin to Drive enabled, you won't be able to enter the Pin if your MCU is dead, and if you try and then use the app to start the car, I imagine the MCU handles the app communication so that also won't work?
 

100KWH

Member
Aug 20, 2018
77
18
Sydney
But if you have Pin to Drive enabled, you won't be able to enter the Pin if your MCU is dead, and if you try and then use the app to start the car, I imagine the MCU handles the app communication so that also won't work?

The way I'm interpreting it is that a MCU-less car may be 'technically' drivable but practically undrivable - i.e. if your MCU died you probably wouldn't be driving your car until it's fixed again. I also recall one time when my MCU temporarily crashed and until I pulled over and restarted it, the AC didn't work - and as it was a hot summer's day, that was killer.

I thought this was interesting as Inside EVs usually put out - in my opinion - pretty junky pieces but this had some more substance behind it.

The article says things like "If your car was made before 2018 and is still under warranty, try to verify if your MCU is working properly." which I have no idea what it means.

If your MCU appears to be in working order, you're not affected by the eMMC issue. At least, that's how I interpret it. That said, a bit of a useless sentence on Inside EVs' part, imo.

Plus it says "Tesla CEO Elon Musk thinks this should be much less of a problem now. Check out the embedded tweet below:" - what embedded tweet? I can't find it.

That tweet is about as vague as it can get and is devoid of additional information to qualify it. Besides, I'm not talking about a newly-delivered MS; I specifically referred to late 2017/2018 and earlier models and the article does the same.
 
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Brian May

Member
Apr 9, 2016
284
64
Melbourne
Even if the image has been recently updated not to write excessively to eMMC on older cars, there is the issue that these cars could already have excessive wear already on their eMMC, just waiting to die. Probably will wait until after the warranty expires...

Wish I could grab a copy of my eMMC "just in case", but sounds like that is not possible without de-soldering the chip, not something I want to do with a car still under warranty.
 

aaron0k

Two failed MCU's on a S40 & S70D; both at 84k.
Apr 1, 2013
665
607
-
I've had two MCU's fail on two different MS's (2013 40 and 2015 70D). Coincidentally both at 84k miles. On had the Black Screen of Death, the other was completely bricked and had to be towed.

It sucks... $$$$
 

TMThree

Active Member
Mar 28, 2019
1,118
1,615
USA
Flash memory has a limited number of times it can be written to. Apparently the linux operating system is set to verbose logging, which means it's writing dozens of lines of logs per second, all the time its active. Eventually the memory can't take additional writes and its effectively bricked.

Model 3 supposedly has twice the memory of the older units, so if this is an issue at 80k, maybe we'll hit it at 160k miles.

I'd prefer if they just disabled verbose logging. It's not like what it's writing is useful.
 
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Tension

Member
Mar 31, 2016
142
66
Sydney Australia
I'd prefer they made that particular memory part removable (not soldered) and thus easily replaceable. If they're wanting to make million mile motor and batteries, the rest of it should be designed to last indefinitely too.
 

100KWH

Member
Aug 20, 2018
77
18
Sydney
Wish I could grab a copy of my eMMC "just in case", but sounds like that is not possible without de-soldering the chip, not something I want to do with a car still under warranty.

Wouldn't mind being able to do this either. Good peace of mind.

I've had two MCU's fail on two different MS's (2013 40 and 2015 70D). Coincidentally both at 84k miles. On had the Black Screen of Death, the other was completely bricked and had to be towed.

Hmm, I'd better drive my MS a bit more then to make 80k miles prior to the warranty expiring! I want MCU2! :D
 

brkaus

Well-Known Member
Jul 8, 2014
7,907
6,397
Austin, TX
Even if the image has been recently updated not to write excessively to eMMC on older cars, there is the issue that these cars could already have excessive wear already on their eMMC, just waiting to die. Probably will wait until after the warranty expires...

Wish I could grab a copy of my eMMC "just in case", but sounds like that is not possible without de-soldering the chip, not something I want to do with a car still under warranty.

There is someone here that can help do that. The mcu needs to be fully removed from the car, but no desoldering required.
 

Jms20nj

Member
Aug 10, 2019
15
24
New Jersey
My 2013 model s is currently at the service center having the MCU replaced after it failed. I think this has to do with the recent update, seems like all of the sudden in the past week there's a ton of people having this issue. It also appears that my service center might be out of the part which would indicate they've done a lot of replacements recently. Originally I was told the repair would be done same day but now I am told they don't know when it will be done
 

100KWH

Member
Aug 20, 2018
77
18
Sydney
I'm seeing a lot more media coverage of the issue now as well (in addition to Inside EV's article). I guess when it's happening to the 2013 units, it's a matter of time as it sweeps across the 14s, 15s and so on.
 
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