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MCU fails for the second time

lunitiks

Cool James & Black Teacher
Nov 19, 2016
2,698
5,939
Prawn Island, VC
That is a confusing invoice. As far as I can tell, they replaced your MCU twice. First time with a remanufactured unit and then with a new unit? Or it was a typo in which case you have no way of knowing which version you got.

Mine was replaced in 2015 with
1004777-00-M

You show the same part number except -40-L. Not sure what the 40 means.
1004777 = Old/pre-facelift mcu.
40-L = Probably something to do with country/area, and sub-revision.
 
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apacheguy

S Sig #255
Oct 21, 2012
5,090
1,247
So Cal
Well, I suspect -L and -M are the subversion as you note, but it’s odd then that I received a more current MCU in 2015 compared to what was shown on his invoice.

The 40 is still odd though. MCUs are not region specific so I doubt it has to do with that.
 

lunitiks

Cool James & Black Teacher
Nov 19, 2016
2,698
5,939
Prawn Island, VC
Well, I suspect -L and -M are the subversion as you note, but it’s odd then that I received a more current MCU in 2015 compared to what was shown on his invoice.

The 40 is still odd though. MCUs are not region specific so I doubt it has to do with that.
But they are.... For example there are 1004777-versions that have a single, purple fakra connector for SIM extender/dongle. (Non-existent on US 1004777-mcus.)
 

MP3Mike

Well-Known Member
Feb 1, 2016
16,186
36,505
Oregon
You may be right, but it's not obvious to me how an arbitrator would rule on a proprietary battery that has no way of being charged but is otherwise "functional." Where do you draw the line? Suppose the cells are good but there's a wiring fault between them. Or what if the AC inverter for the motor blows -- is the "drive unit" still good? These definitions seem blurrier to me than the modular household equivalents of putting some AAs into a plug-in charger.

You draw the line where the warranty states it is. The battery which is a separate piece, and can be removed from the car, will still be functional at the end of warranty. The battery is a single unit so everything inside it is covered. (The cells, wiring, BMS, connector, cooling passages, etc.) The drive-unit, which includes the invertor, will still be functional at the end of the warranty. Everything else is covered by the standard bumper-to-bumper warranty. (All of the cabling that connects them and the electronics that control them.)
 

robby

Member
Aug 25, 2014
642
361
Andover, MA
You draw the line where the warranty states it is. The battery which is a separate piece, and can be removed from the car, will still be functional at the end of warranty. The battery is a single unit so everything inside it is covered. (The cells, wiring, BMS, connector, cooling passages, etc.) The drive-unit, which includes the invertor, will still be functional at the end of the warranty. Everything else is covered by the standard bumper-to-bumper warranty. (All of the cabling that connects them and the electronics that control them.)

Is there a place where Tesla defines the "drive unit"? I checked the warranty (or at least the version that shows up in my Tesla account docs) but didn't see it.
 

apacheguy

S Sig #255
Oct 21, 2012
5,090
1,247
So Cal
I’m curious as to what exactly happens here. If the flash is going bad, does the kernel crash every time the OS attempts to write to a bad sector? Is this unique to Tesla’s ext3 or kernel? Most FS recognize that certain sectors are bad and don’t perform read/write on those sectors.

Also, when the eMMC finally does fail (and the MCU is completely dark), does it fail completely meaning that the boot procedure doesn’t get past the bootloader? Or is it still able to boot the kernel, but the UI never comes up because all the Qt binaries are stored on the eMMC?
 

demundus

Active Member
Jul 5, 2015
1,335
868
Oceanside, CA
I’m curious as to what exactly happens here. If the flash is going bad, does the kernel crash every time the OS attempts to write to a bad sector? Is this unique to Tesla’s ext3 or kernel? Most FS recognize that certain sectors are bad and don’t perform read/write on those sectors.

Also, when the eMMC finally does fail (and the MCU is completely dark), does it fail completely meaning that the boot procedure doesn’t get past the bootloader? Or is it still able to boot the kernel, but the UI never comes up because all the Qt binaries are stored on the eMMC?

I'm not sure, @wk057 can probably answer better... although everything you wrote has trappings of things he explained to me, so you're probably right or really close. When mine failed he suspended certain sectors to keep it going until it all but died and was unable to boot. Thats the plain english of it
 

cwerdna

Active Member
Jul 11, 2012
3,636
2,544
SF Bay Area, CA
I don't understand why this is not a recall thing since they all WILL break down do to poor design.
Recalls are generally for safety defects or non-compliance w/FMVSS. I don't think a failing MCU qualifies as either of these.

I've also seen recalls for wrong phone numbers in manuals.

They could extend the warranty or have some sort of service campaign.
 

fsch

Member
Sep 21, 2015
151
177
Montreal, QC
Resurrected MCU!

The MCU didn't wake up during the weekend in my 2013 MS with 180 000+ km and appeared to be completely dead. Tried to reboot 24 times (according to Tesla tech who looked at the logs) with and without pressing the brake pedal, also tried to remove fuse F-51 a couple of times, nothing worked.

After a couple of days driving without fan/heating (with fog problems in the windshield, the fan is really the only "critical" component that doesn't work), I went to the service center yesterday, ready to spend 4k$+ Canadian. However the part was back-order in all North America for more than 2 weeks! They gave me a loaner in principle for that period.

But then they called me back a couple of hours later to tell me that they had been able to restart the MCU. I don't know what they did exactly, I just know that they connected a laptop equipped with some Tesla diagnostic software. So it's something I can't do myself.

Still, it's good to know that it's possible.

They don't know how long it will last. The MCU may fail again tomorrow, in one week, one month, one year, or may last for the rest of the car's life. Maybe my MCU has 9 lives! Anyway, I will certainly look to buy the new MCU when it's available.
 
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jevan43

Member
Jan 2, 2016
180
55
Austin, TX
Just thought I'd chime in here real quick...2013 P85+ 56k miles....12/13 build...had MCU replaced 2 months ago (after waiting since August) Tune-In stopped working, NAV would periodically say I was in Russia instead of Texas..phantom reboots weekly etc..

Last night out of nowhere MCU just shuts off can't get it back on..took car in to service today they game me a loaner and basically said "we'll be in touch.."
 

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