Model S

MCU replacement

edited November -1 in Model S
Apologies for the long post but I I wanted to share my recent experience with Tesla and the Dallas Service Center.

First I understand that there is and inherent risk buying a used car and that was my decision. I own that and much of my post is based out of pure frustration and disappointment.

But after reading countless forum articles and car reviews testifying the Model S reliability I was convinced that Tesla makes a solid and reliable product and that generally owners are well cared for, hence I shouldn’t be to concerned. After finally getting the service records It was clear that this was not a problematic car.

My experience has been quite the opposite and what I came find out is that if you don’t purchase a new or CPO vehicle from them and something goes wrong, they will make you pay for it. In every sense of the word.

One month after ownership my worst fear happened. After firmware update the MCU started giving me technical issues. Ultimately it failed leaving me with a $3,500 bill and an inoperable car. oh and they’re charging me $20 to tell the AC is working fine. The Service managers response,” most of the technical parts on the car like the MCU have a shelf life of 4-6 years so this is actually pretty typical.”

Are kidding me? A six figure car that has been marketed as a ultra reliable game changer precisely because of “less moving parts” has imminent failures by design. I would love to see a salesperson make that pitch to a potential buyer.

I have read and shared with the Service Center various accounts were the MCU had been replaced under good will and given that I have only one had the car one month the idea of spending nearly 3k in repairs is absolutely ludicrous.

On another note my DU needs to be replaced under warranty but incredibly it turns out that hubs needs to be greased. Grinding/milling, droning, clunk sounds and present but no need to replace the DU apparently. So Tesla is more than happy to charge a huge bill on a non warranty item but will not address a major fault under warranty. Let me guess, that issue ha a “longer shelf life”. Unbelievable.

Do I like the car. Absolutely. It’s safe, amazing to drive, gorgeous and a technical marvel.

Has Tesla lost my trust a customer and a brand advocate over petty nickel and dimming? Absolutely.

They had the opportunity out of “goodwill” to make this an exceptional experience but decided to make sure that if you don’t buy from them it’s going to hurt. You’ve made your point Tesla and after working in marketing for over 25 years I have learned that once you’ve lost a customer it’s very difficult to gain they’re business again.


  • edited July 2019
  • edited July 2019
    @ducatismo - Sorry about your problems, but it sounds like you bought a used car that is out of warranty. Why should Tesla provide free service forever? No car company does. You could buy a new car with a warranty, buy a used car from Tesla with a warranty, buy a used car from a dealer or third-party that is still in warranty, or what it appears you did, buy a used car that is out of warranty and has many miles/years on it.

    Next, why would Tesla replace the DU if the hubs need to be greased? So you want parts replaced that have nothing to do with an issue? I guess if you want to pay for a DU, they can replace it, but not sure why you want to waste your money. Tesla has no obligation to replace random parts that are not bad even if the car was in warranty.

    If you did pay $100K for the car (very doubtful), you're upset at spending $20 to diagnose something? Seems like a bit of a crazy rant expecting to get lots of free service.

    Again, I'm sorry for your problems, but it seems way over the top and Tesla is conducting themselves as good if not better than any other automotive company.
  • edited July 2019
    lilbean - you're too verbose.
  • jjsjjs
    edited November -1
    Ditto lilbean
  • edited November -1
    They made you pay for repair of an out-of-warranty vehicle?? The nerve!
  • edited July 2019
  • edited July 2019
    You did it again!
  • edited July 2019
    "a shelf life"

    If this is an accurate quote, I wonder if the Tesla service manager, or you. or both, understand the meaning of the term,
  • edited July 2019
    I think OP may be a little shelf(life)ish.
  • edited July 2019
    Sorry to say it is true the MCU may only last for four to six years if the car is used daily. I saw a “Rich Rebuilds” video on YouTube. The company in So California he was visiting repairs Tesla. They showed how an SSD chip was being over worked to death. It seems the software wants to store almost everything the MCU does. There may be a very good reason for this however it will kill the chip in about four years of daily use.

    The good news is, it is on a small easily removable board. It can be quickly replaced once the MCU is removed from the car. The bad news is, to save time once Tesla removes the MCU you are getting a new one. They don’t repair the old one.

    Cars that are not driven often may get many more years before this problem will surface. However unless the software changes all our cars will most likely have this problem.
  • edited July 2019
    Does MCU2 resolve this SSD 4-year failure rate issue?
  • edited November -1
    "The bad news is, to save time once Tesla removes the MCU you are getting a new one. They don’t repair the old one."

    So that means if you request it at the time of the service write-up, and you are out of warranty, Tesla MUST return the old one to you by law (at least in California).

    I will bet dollars to donuts that they will claim it is a "core exchange," which would mean they DO repair them, just not at the Service Center.
  • edited November -1
    @Tropopause & @Anthony - While it is known that the MCU's flash drive will fail at some point, it is a lot of conjecture as to when that may happen. There have been some failures in 4+ years of operation. Only Tesla knows if this is a significant problem or in the noise.

    I think hourly usage is a larger factor than age, but we only know milage - which relates to hourly usage. There have been some cars with 200K miles without a MCU replacement, so it's not at all clear why some fail early or if many will. It may bet that there is some customer use case that uses far more writes than another.

    For a totally made up example, perhaps using streaming stores the data in flash memory and causes a large amount of writes, so that it doesn't last as long. Another owner uses FM radio that uses no writes into the memory - so it may last far longer. This is just an example, and I have no idea what is being written to the flash memory (other than logs).

    I've only been able to find that the new MCU2 uses at least twice as much flash memory, and possibly 4 times as much. At double the memory, it may mean it could last twice as long if writes are similar. With a different CPU design in MCU2, I'd be hesitant to make any assumption. It could be the software operates differently and could last 100 years or 1 year.
  • edited July 2019
    My god... What did you expect?
  • edited November -1,
    Thanks for the info.
  • edited July 2019
    Well look on the bright side. If your car is still in warranty, maybe in about 2 years when the MCU dies you can actually have them put in a MCU2 or 3 without a yellow border. I would like to be patient and non-sarcastic, but seriously I have had a yellow border for a year and still getting the run around.
  • edited October 2019
    The response I received was "Greetings from Tesla Mobile Service! At this time there is no way to retrofit your vehicle from MCU 1 to MCU2. We will now cancel your mobile service appointment "
    That was Oct 7th 2019. I am very sad...
  • edited October 2019
    That's can do to upgrade MCU1 to MCU2, just brought my car to the service center for wheel alignment, asked about the MCU upgrade, total rumor, not happening,, as for the FSD hardware upgrade, true for FSD paid customers, will be free, and now in progress (sadly I am in line for another couple of months or even into the beginning of next year).
  • edited October 2019
    2014 S60-CPO with 3 years left on the warranty. I have the bubble(it’s slowly getting bigger, but not affecting its use) at the top of the center screen...reading thru this, it seems that either 1-the screen will get replaced, but the MCU1 is not replaced, or 2-screen replaced, but MCU2 included, cause MCU1 inventory running low.

    So, would it be better to wait? And has anyone had the screen replace under warranty, with the MCU2 retro as part of the fix, and was that covered under warranty?
  • edited October 2019
    @mysin...according to the service center, no MCU2 replacement for any MCU1, screen replacement only (currently they are fixing the yellowing edge of the screens with a special machine (unfortunately the machine itself was broke when I took my car in, consequently my screen was not fixed, but tagged for future visits)... even if the MCU1 is defective, they would find a rebuilt (if no new inventory), I believe it to be true, just think, for any ice car, replacement parts are always available for aged models, why not an EV?
  • edited October 2019
    Elon has stated that he is working on it. I would say try again in Dec-Jan. Once all the FSD hardwares are all retrofitted.
  • edited October 2019
    “... We are working on establishing an upgrade for MCU1 to MCU2. This will be a customer pay option, but specific details have not yet been released. I would touch base with your local service center from time to time as they will have more information as to when they will be able to complete this upgrade.”

    Received in email from Tesla today.
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