Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Yet Another MCU Failure Post

This site may earn commission on affiliate links.
Well everybody, it just happened to me. I upgraded from my 2014 Black Tesla Model S (which I loved!) to another fantastic 2015 Silver Tesla Model S. Upgrades for me include having autopilot 1, which alone is a huge upgrade, dual motor capability, and updated interior, among many other items. However, shortly after taking possession of this awesome car, the MCU failed on me and has not come back on yet!

Thankfully, this failure happened right near to my home so I wasn't too far out of service, HOWEVER, here is the kicker.

I arrived at my home with 30 miles on the tank. Unbeknownst to me, with the MCU going out, I have been unable to turn off the A/C unit. As such, there has been a signifcantly larger phantom drain to the battery, moreso than I knew! So cue me the next day noticing the battery was at 4 miles instead of 30. I was certainly taken aback, so I decided to plug in to the wall unit (normally I would have charged at work, as we have charging stations there), however, with it being such a slow rate of charge due to all of the normal vehicle systems which are unable to be turned off due to the MCU going out, the vehicle only charged 9 miles over the course of 9 hours. Crazy, right? It gets worse.

I came back the next day to the car being at 0 miles rather than 14, plus any additional charge. Talk about another surprise! So I decided to schedule a time to take the vehicle to the SC to have the MCU replaced and have also filed this issue away with the numerous other NHTSA complaints.

So, any thoughts on how I could creatively get the car to charge prior to my having to take the vehicle to the SC next week without having to get a tow? Anyone know if the NHTSA is going to force Tesla's hand in recalling the MCUs? Will the coronavirus get me before I can fix the vehicle?
 
  • Informative
Reactions: Russell
I was just about to post about this exact issue! I have a 2014 Model S, out of warranty, pre-facelift, with AP1 and about 95,000 km. In retrospect, I was probably having issues for months (slow / sluggish interface and music streaming, internet connectivity dropouts, and voice commands not working) until two days ago my MCU completely failed on me. After trying (but failing) to reboot the MCU, the instrument cluster reset to imperial units, time zone was reset, and I lost all odometer and historical data.

I also had an A/C unit that was permanently on even when it was supposed to be turned off while in the parking lot at work. I had a sneaking suspicion so I went to check the car after a couple hours and noticed that I was losing over 10 km/h of charge. It probably didn't help that it was a really hot and humid day too.

Tesla Toronto confirmed my suspicions about the MCU failure. After complaining about the A/C drain on the battery, they asked me to bring the car to the service centre which was thankfully pretty close by and they were able to fit me in for a quick reset of the car. Took about 20 minutes and now the A/C now shuts off after I leave the car. The car is driveable but I have lost all turn signal functionality plus obviously all other functions controlled by the MCU. I noticed that although the turn signals don't work, the emergency 4 way flashers work. Why are these two functions separated even though they act on the same lights? Also charging rate is reduced to 8A (normally I get 40A) when plugged in at home.

Tesla Toronto is ordering me a replacement MCU which will come in possibly by the end of the week (the quote says a remanufactured MCU #1098010-99-H) for $1310 CAD. $1865 CAD in total including labor and tax. They quoted a 2 year warranty on the replacement. I saw posts about possible 3rd party replacements but since this is my daily driver, I want my car back up and running as reliably and as fast as possible... I was actually expecting to pay more for the replacement MCU but I'm glad that it looks like the costs are coming down.

In the fantastic 5 years that I've had this car, this has been the biggest and most inconvenient issue that I've had with the car....

Does anybody know if this remanufactured MCU has an upgraded eMMC for greater longevity compared to my original MCU? It really sucks to hear about this memory issue and I'm really hoping to be able to drive the car for several more years.

I see NHTSA complaints have been filed, but since I am in Canada is there anything I can do to add my voice to this issue?
 
My understanding of the MCU2 replacement is that the emmc chip is installed differently, therefore, it should not run the same risk of going bad in the same fashion. As to whether or not the MCU2 is more reliable is another question (see bubbling issue and the yellow tint issue)!
 
My understanding of the MCU2 replacement is that the emmc chip is installed differently, therefore, it should not run the same risk of going bad in the same fashion. As to whether or not the MCU2 is more reliable is another question (see bubbling issue and the yellow tint issue)!
Nice that you are able to get an MCU2 instead of a rebuilt MCU1. There is no comparison.
 
Fingers crossed I will be able to :confused: I have scheduled an appointment with the SC stating my issue and what all is going on and what I suspect will be the issue and repair (being an MCU2 replacement) but knowing how lackluster the Nashville service center has been for me in the past, I'm not sure
 
Wow, if I didn’t know better, these could have been my posts.

2014 Model S. In the past few weeks, upon restart, the air vent would click a fair amount, and I was quickly losing cell service after reboot.

On Saturday (my first mistake – Service Centers weren’t open), I rebooted and the screen never came back on.

Went in to work and after coming out a couple of hours later, the AC was still running.

AC continued to run for another couple of hours before I returned home to research how I could turn it off.

Things I tried, unfortunately I'm not sure of the exact order, trying to cut all the power until mobile service could get to me:
  • Opened the driver’s window, so I could get in in the case of no power.
  • Plugged in the car to charge to restore some of the lost juice. Car started charging as indicated by the green charging circle.
  • Removed the frunk coverings to get to the battery.
  • Removed the negative battery terminal.
  • Tried to remove the high voltage battery clip under the hood, over by the air vent filter, but failed.
  • Unplugged the car, because it was now the most expensive part of the day for electricity.
  • Reassembled everything, including reconnecting the battery.
Somewhere along the line, the AC turned off. I’m certain it was after I opened the driver’s window, but I’m not sure of the exact series of events, unfortunately.

I have no idea why it turned off, but I’m happy it did. I’m sharing both to commiserate, but also in case anyone else finds a correlation – it would be handy to know how to turn off the AC if it were to happen again.

Good luck everyone.

PS: tonight I just went out and the backlights of the window buttons and the hazard lights were on. I might open her back up again to disconnect the 12v… what a pain…
 
  • Informative
Reactions: Russell
Anyone know if the NHTSA is going to force Tesla's hand in recalling the MCUs?

They might, but I wouldn't count on it being anytime soon. I was hoping that NHTSA opening a formal investigation and requesting all of the information about the situation would have prodded Tesla into doing something proactively. (But they have until August 7th to respond with all the data.)
 
Not an update, but more of a question for the more experienced out there. . . Let's say hypothetically Tesla has to recall all MCU 1s and do a complimentary upgrade as required by the NHTSA. Is there a precedent with other car manufacturers, where if a consumer has to pay for the fix prior to the recall being required, are the consumers reimbursed?
 
Not an update, but more of a question for the more experienced out there. . . Let's say hypothetically Tesla has to recall all MCU 1s and do a complimentary upgrade as required by the NHTSA. Is there a precedent with other car manufacturers, where if a consumer has to pay for the fix prior to the recall being required, are the consumers reimbursed?


I had a BMW 650i convertible before my Model S. The BMW had a problem with the power convertible top getting stuck halfway sometimes. It was an obvious design flaw. Some people had BMW try and fix it at a cost or a third party company. Years later, I received a letter stating that BMW was to make good on these repairs. If you paid to have this addressed, you would get reimbursed after providing proof. So maybe Tesla will have to reimburse people.
 
  • Helpful
Reactions: RabidYak
I just had this happen to me, I took my MCU out and sent my Tegra board to a member that replaces the chip and if not corrupted all your important files on the new chip and send it back to you.
I was quoted from Tesla $2500 + labor from MCU 2 upgrade or $1600 + labor for a MCU 1 (refurb) after reading on this if Tesla would just replace the faulty chip ($20-$80) it would be less expensive to replace.
I opted to remove the MCU, take out Tegra card and send it to a member that replaces them with a larger capacity chip and transfers your cars data back on to it and sends you a backup copy and it cost $500
 
  • Helpful
Reactions: RabidYak
What if you paid to upgrade to MCU2 rather than MCU1? Would MCU1 cost be reimbursed?
The operative word in that phrase is "upgrade" which will bring with it a lot of question marks. You technically didn't replace a faulty MCU1 for the purposes of getting the car functional again but Tesla could be compelled to offer a set amount of reimbursement for anyone who replaced their MCU with ANY version MCU.

A prime example I personally experienced was when my Tacoma had a recall on the rear leaf springs. Turns out that they were breaking and impacting the fuel tank and puncturing them causing potential for tremendous issues. Toyota sent a letter out to owner advising us to not drive the truck. The kicker is that they didn't yet have a solution... just to not drive the truck. I took it upon myself to get a set of Dakar aftermarket leafs with a 3" lift along with upgrading my front suspension as well. I sent the receipt to Toyota and they reimbursed me for the amount they felt like they would have paid to swap in a new lead pack anyway. In that situation, Toyota did right by me so I was happy and basically had no down time so everyone was happy.

In this case, we have no such TSB from Tesla on this matter. It's only in the preliminary investigation stage. Maybe nothing will come of it, maybe something will. Now, ask yourself, given Tesla's recent trend towards going cheap on every damn little warranty cost and screwing customers over to save a few bucks regardless of how it tarnishes the Tesla brand... what do you think they will do? Personally, I'm not "upgrading" anything and will wait until Tesla forms an answer to this as to keep from potentially eliminating myself from any sort of recourse.

If your MCU1 is currently functional I'd sit tight and wouldn't do anything until I wait and see how this all plays out. If you're in a rush to "upgrade" to MCU2 just look at it as a sunk expense and if you get some of it back later it's a bonus.
 
  • Helpful
Reactions: Greg29 and RabidYak
I

Tesla Toronto is ordering me a replacement MCU which will come in possibly by the end of the week (the quote says a remanufactured MCU #1098010-99-H) for $1310 CAD. $1865 CAD in total including labor and tax. They quoted a 2 year warranty on the replacement. I saw posts about possible 3rd party replacements but since this is my daily driver, I want my car back up and running as reliably and as fast as possible...

Wow, that is a good deal: $970 US for the MCU and $1381 US total installed.

If you sent it off to Tony it would cost you about $700 US including shipping back and forth, possible duties, and you would have to remove and reinstall it, and Tony doesn't give 2 year warranty :)

Oh, and get them to upgrade it to LTE if you don't have it already; should be only another $120 or so.
 
For those of you interested in my challenge, I have yet to be reached out to regarding the estimate and what repair is to be done for my appointment tomorrow that I have been scheduled for for the past week. Y'all, the Nashville service center has become a joke.

I have had to call tesla 3 times to see if I could get someone on the line to talk to about my repair, thewill happen. Two of the times I talked with a fellow who was so unhelpful and basically said "come in on Thursday, that's the best I can tell you about your repair." The last time I had a lady who was helpful and reached out to my local center to get them to get me on the line. An hour later I get the attached text from my service center.

Note, even with this text, I still haven't gotten a repair estimate, been told what will happen, AND it is going to take 2 weeks for the repair? Surely it shouldn't take that long to upgrade an MCU, right? I am at my wit's end with this and have no clue how to proceed except by going by the fellows words from earlier "just come in on Thursday."
 

Attachments

  • Screenshot_20200722-135159.png
    Screenshot_20200722-135159.png
    1.1 MB · Views: 150
For those of you interested in my challenge, I have yet to be reached out to regarding the estimate and what repair is to be done for my appointment tomorrow that I have been scheduled for for the past week. Y'all, the Nashville service center has become a joke.

I have had to call tesla 3 times to see if I could get someone on the line to talk to about my repair, thewill happen. Two of the times I talked with a fellow who was so unhelpful and basically said "come in on Thursday, that's the best I can tell you about your repair." The last time I had a lady who was helpful and reached out to my local center to get them to get me on the line. An hour later I get the attached text from my service center.

Note, even with this text, I still haven't gotten a repair estimate, been told what will happen, AND it is going to take 2 weeks for the repair? Surely it shouldn't take that long to upgrade an MCU, right? I am at my wit's end with this and have no clue how to proceed except by going by the fellows words from earlier "just come in on Thursday."


Just to give you a taste of my experience. Over a week ago, after driving my 2015 Model S around half the day, out of nowhere the MCU goes black and doesn't come back. It just kept cycling as if I had rebooted and would get to the Tesla logo and go black again. I tried to reset it with the steering wheel controls but nothing worked. I couldn't turn on the radio and even turn on the a/c, and it was steaming outside. I made an appointment via the app saying in the description that I thought the MCU died. The earliest appointment was for 2 weeks out. I was bummed but I made the appointment.

I got a text from the Tesla Paramus dealer about an hour or two later saying that they looked at my appointment and wanted to help expedite my repair. They asked if I could bring it in the next day! I said yes and asked for a loaner since they might have to keep the car for a couple days because I thought it might be the MCU. They said they didn't have any loaners as of now but would give me $100 in Uber credits. I didn't feel comfortable taking an Uber during this pandemic and would arrange for my own transport but I told them to please let me know when a loaner was available. They agreed.

I went to the dealer first thing the next morning to drop it off. They said they agreed that it might be the MCU but will have to check to make sure. If it was, it would take a couple of days to repair maybe longer to get parts and repair it. To my surprise they were able to get me loaner since they knew the repair might take a couple days.

At about 5pm I get a text that the car was ready to be picked up! I texted back asking if it was the MCU and they said no, that the software got hung up. They were able to push the last update again and that fixed the issue.

I say all this to say, at least in my experience, you have to give them a chance to diagnose the issues. I know it can be frustrating to be in the dark but be patient.

I will say that I have had NOTHING but great experience with the Paramus dealership. They have been amazing.
 
Last edited:
Just to give you a taste of my experience. Over a week ago, after driving my 2015 Model S around half the day, out of nowhere the MCU goes black and doesn't come back. It just kept cycling as if I had rebooted and would get to the Tesla logo and go black again. I tried to reset it with the steering wheel controls but nothing worked. I couldn't turn on the radio and even turn on the a/c, and it was steaming outside. I made an appointment via the app saying in the description that I thought the MCU died. The earliest appointment was for 2 weeks out. I was bummed but I made the appointment.

I got a text from the Tesla Paramus dealer about an hour or two later saying that they looked at my appointment and wanted to help expedite my repair. They asked if I could bring it in the next day! I said yes and asked for a loaner since they might have to keep the car for a couple days because I thought it might be the MCU. They said they didn't have any loaners as of now but would give me $100 in Uber credits. I didn't feel comfortable taking an Uber during this pandemic and would arrange for my own transport but I told them to please let me know when a loaner was available. They agreed.

I went to the dealer first thing the next morning to drop it off. They said they agreed that it might be the MCU but will have to check to make sure. If it was, it would take a couple of days to repair maybe longer to get parts and repair it. To my surprise they were able to get me loaner since they knew the repair might take a couple days.

At about 5pm I get a text that the car was ready to be picked up! I texted back asking if it was the MCU and they said no, that the software got hung up. They were able to push the last update again and that fixed the issue.

I say all this to say, at least in my experience, you have to give them a chance to diagnose the issues. I know it can be frustrating to be in the dark but be patient.

I will say that I have had NOTHING but great experience with the Paramus dealership. They have been amazing.

That is awesome! I wish I had gotten a prompt response like this.Only the day before did I get a text from the SC. I didn't mention this earlier, but I was told by one Tesla rep that they had already ordered 3 parts, 2 of which had been received at the service center. With that being said, the service center hasn't even seen my car yet, so how should they know what parts to order?
 
I didn't mention this earlier, but I was told by one Tesla rep that they had already ordered 3 parts, 2 of which had been received at the service center. With that being said, the service center hasn't even seen my car yet, so how should they know what parts to order?


They do that all the time. It helps save time waiting for parts to arrive. That way your car is not in the shop just sitting there while they wait for parts.
 
Well, yesterday, I got in my car and found the touch screen blank. Scroll wheel reboot didn't work. I even went as far as to pull and reinsert the MCU fuse. Seems like this could be the eMMC failure. I setup a mobile service appointment for Friday, then got a call from someone at Tesla (510 number), who, after hearing that I'd already tried to reboot it, rescheduled my appointment to the local service center on 8/3. Fortunately, I have the extended warranty for another six months, but it concerns me that he was talking like that had some tricks to get it working again. If the service center manages to extend the life of my MCU for six months, I'll be out of warranty when the eMMC fails for good. I'm also not thrilled that car has no turn signals!
 
  • Like
Reactions: badgirl