MCU/FSD Upgrade, 12V Battery Dying Repeatedly in 2017 Model X

[EagleOne]

I've been scanning Google generally and TMC in particular to see whether or not I'm the only one encountering this issue.

I had my MCU (AP 2.0) upgraded when I brought my MX in for the FSD computer upgrade in the middle of June.

Everything went fine, my settings were even largely preserved which was unexpectedly pleasant.

A week after the upgrade, I got a notification that the 12V battery needed replacement. This wasn't too surprising as my first 12V battery had to be replaced after 18 Months and this was almost exactly 18 months after that. When I asked the the mobile tech about it he told me that 18 months is pretty normal for these cars so.. yay warranty.

About three weeks later, the car was bricked. Dead. Unresponsive. I called Tesla roadside assistance and, when the tow truck arrived, the guy was able to just jump the car and things came back online and everything seemed normal. Shipped the car to the service center where they did nothing but sit on it for 5 days and then swapped out the battery for a new one.

Two weeks later, you guessed it, dead again. Same process as above. Car was in the shop 6 days this time. At the end of which I found they did ... no diagnostics and swapped the battery again.

5 days later, shockingly, dead again. This time car was picked up by a different service center who have been somewhat more diligent about keeping me apprised of what is going on. They *are* trying to reproduce the issue but it's taking a long, long time. The car has been in the shop for over 15 days now.

1) Has anybody experienced repeated 12V battery failures like this?
2) At what point is it reasonable to declare the car unfit for use and look to Tesla to replace it?

It's one thing to face the morning with concern that your car may or may not work when you're driving a beat up used car in high school, but I'm really not pleased that my rather pricey state-of-the-art vehicle is so vastly less dependable than... well.. ANY car I've owned before.

Thoughts for how I can proceed? Commiserations about facing the same issues? I'm feeling pretty down here.

Thanks!

Marc

 

[Tam]

...repeated 12V battery failures...

12V dies for a reason. Tesla needs to find out why.

 

[P85_DA]

Thoughts for how I can proceed? Commiserations about facing the same issues? I'm feeling pretty down here.

read a lot of 12v threads here but not repeated failures like yours. I have a 2018 and had mcu replaced but don’t see anything similar. Seems like local to your car and unfortunately only Tesla can troubleshoot ..I feel for you though being away from car that long

 

[ecarfan]

This wasn't too surprising as my first 12V battery had to be replaced after 18 Months and this was almost exactly 18 months after that. When I asked the the mobile tech about it he told me that 18 months is pretty normal for these cars so.. yay warranty.

Sorry to hear about your problem. Very odd indeed. My July 2017 X with 48K miles (and no MCU replacement) is on its original 12V battery. I’ve had no 12V issues.

 

[Seattle Tom]

Sorry to hear about your problem. Very odd indeed. My July 2017 X with 48K miles (and no MCU replacement) is on its original 12V battery. I’ve had no 12V issues.

June 2017 build here and same as above - original 12V battery and MCU/FSD upgrade done about two months ago. Ive read the horror stories on the forum of course and just kept my fingers crossed. Yours sounds really bad...I’m sorry it’s happening.

 

[TechVP]

June 2017 build here and same as above - original 12V battery and MCU/FSD upgrade done about two months ago. Ive read the horror stories on the forum of course and just kept my fingers crossed. Yours sounds really bad...I’m sorry it’s happening.

My X build/delivery date was March 2017. I consumed about 37 months out of my first 12 battery, before the warning appeared. Had to replace it right when I predicted it was due. And bingo, right during the Virus lockdown.

For you guys in June and July 2017, stay tuned... it is about time. I replaced mine just over 58k miles. No warranty for me -- and none expected.

Meanwhile for the OP, my vote is that something is amiss... 18 months is about 1/2 the life expectancy that a) I experienced and b) half of what the techs told me when I bought my X. They insisted 36 months to me... and the Tesla SC techs were nearly spot on in my real world experience.

I think Tesla owes you a better explanation.
-TechVP

 

[mjptech]

...
2) At what point is it reasonable to declare the car unfit for use and look to Tesla to replace it?
...

Typically that falls under the state's lemon laws, and, per GA Lemon Law | Georgia Department of Law's Consumer Protection Division, in Georgia, it looks like it's the first two years or 24,000 miles, whichever comes first.

Beyond that, your recourse is more than likely limited to getting a good-will mediation result in your favor through Tesla, or, reaching out to a lawyer on your own dime.

Also, don't forget, you can go for where it hurts Tesla the most - social media. Just be ready to be inundated with Tesla fans going after you if you do that. It's the world we live in.

 

[Akikiki]

@EagleOne, have read about your plight, I know what I would be doing. I would first make sure we are on the same page and point out for the less gifted, the problem started and has persisted with the MCU2 Upgrade. I want it replaced. I don't want my money back, I want a different one installed. Find another one. Since they have already wasted all these days, it won't matter much to put a different one in, and see if the problem continues. None of us have any idea if a replacement MCU2 was considered, so it necessary to bring that up and to their attention. If it means asking (insisting if necessary) to talk to a region service boss, so be it. But stop simply replacing batteries and try the most likely cause - where it started.

 

[EagleOne]

Thank you all for this feedback.

My main issue is that I'm kind of in a vacuum with respect to where my car is on the spectrum so this information is especially helpful.

I am working with the SouthEastern Regional manager at the moment so I have the ear of someone who should be able to make things happen.

Since I'm airing my car's dirty laundry, I also wanted to see if my phantom drain (vampire drain?) is on par with what others with similar vehicles are seeing.

I consistently see 4%-6% per day which seems excessive. The car essentially NEVER sleeps (using TeslaFi as my primary monitor).

I currently have a loaner model S and it sleeps like a baby and has virtually no phantom drain.

 

[VikH]

Thank you all for this feedback.

My main issue is that I'm kind of in a vacuum with respect to where my car is on the spectrum so this information is especially helpful.

I am working with the SouthEastern Regional manager at the moment so I have the ear of someone who should be able to make things happen.

Since I'm airing my car's dirty laundry, I also wanted to see if my phantom drain (vampire drain?) is on par with what others with similar vehicles are seeing.

I consistently see 4%-6% per day which seems excessive. The car essentially NEVER sleeps (using TeslaFi as my primary monitor).

I currently have a loaner model S and it sleeps like a baby and has virtually no phantom drain.

Glad to hear you got to the regional manager.

Regarding vamp drain, my 2017 MX P100DL will sleep every chance it gets (I have Energy Savings On and Always Connected Off). My vampire drain rate is between 1-2% per day. Maybe you have to update your TeslaFi settings for your new MCU2? Your vamp drain could be related to your 12V dying too.

 

[EagleOne]

Glad to hear you got to the regional manager.

Regarding vamp drain, my 2017 MX P100DL will sleep every chance it gets (I have Energy Savings On and Always Connected Off). My vampire drain rate is between 1-2% per day. Maybe you have to update your TeslaFi settings for your new MCU2? Your vamp drain could be related to your 12V dying too.

Thanks VikH,

I definitely want to hear what's normal for other MX cars. I think I've been in a bit of a bubble where I only hear about the oddball things via these forums.

Interestingly after I upgraded to MCU2 the "Powersaver" slider and "Always Connected" checkbox options disappeared. It seems to be normal after the upgrade, at least from my searches on the topic. So I have to assume Tesla thinks they've optimized this for the newer computer.

I can claim that I have tried pretty much every possible combination of settings in TeslaFi (including blocking access to it) to try to find some means by which sleep mode could be encouraged. The no sleep and vampire drain issues predated the MCU2 upgrade and seem no better or worse post upgrade. The main difference post upgrade is the repeating 2-3 week failure of the 12 V battery which has now brought things to a head for me.

 

[Akikiki]

I can claim that I have tried pretty much every possible combination of settings in TeslaFi (including blocking access to it)

There's your does not sleep problem. And you don't simply block TeslaFi. Only way is change your password and completely deny it access.
Those of us that have been here a while know. Case closed.

 

[BigMskiman]

I did 4.5yrs and original 12V battery, ~60k miles. MCU1 black screen death, got MCU2/AP2.5 infotainment upgrade. Three weeks later, got the 12V warning, had the ranger come and replace. Ranger says you have about 2 weeks after the warning, for full death to happen.

All is good so far.

Sorry to hear 12V failure keeps happening, it should be able to be tracked down.

old |v2020.28.5|AP2.5,MCU2,PUP|
new |v2020.32.3|AP2.5,MCU2,PUP|

 

[EagleOne]

There's your does not sleep problem. And you don't simply block TeslaFi. Only way is change your password and completely deny it access.
Those of us that have been here a while know. Case closed.

Sorry Akikiki, I should have been more clear. Whenever I decide to sit down and try to figure out sleep / Vampire drain, I change my password and then consider what, if any apps I'll log back in with including Tesla's own app. I went for two weeks after changing my password with NO apps touching the car and no difference.

 

[EagleOne]

I did 4.5yrs and original 12V battery, ~60k miles. MCU1 black screen death, got MCU2/AP2.5 infotainment upgrade. Three weeks later, got the 12V warning, had the ranger come and replace. Ranger says you have about 2 weeks after the warning, for full death to happen.

All is good so far.

Thanks for the vote of confidence BigMskiman. I'm pretty impressed with how long your 12V battery lasted. It definitely puts the lie to 18 months being "about normal".

Interestingly, except for the first time I received the warning (a week after the MCU upgrade), I have not received any warning for each of the 3 subsequent failures. I'm not sure if it says something about the threshold required for the warning or if it's more about how fast the battery depleted.

The Tesla folks were just here to drop off a replacement loaner car and I again spoke with the regional manager. I gave him some more specifics regarding how and when I charge the car to see if he can mirror it when the SC is trying to capture the fault.

He has high confidence that they can get to the bottom of this.

As eye opening as it has been driving these loaner cars lately (to see what's better/not as good as my car) there's nothing like driving your own vehicle. That along with comments such as yours is putting my car closer to the bottom of the heap..

 

[OhFrankie]

Interestingly, I upgraded the MCU and FSD computer in my March 2017 Model X 100D on Thursday, August 13th. One week later, on Thursday, August 20th, I received an alert that the 12V battery needed to be replaced. I had the battery replaced on Friday, August 28th. No TeslaFi here, just Blackvue cameras and now a Samsung SSD drive for Tesla Cam. Here's to hoping I do not have another battery failure too soon!

 

[dailo]

I had my 12V replaced at the same time doing the MCU2 upgrade, but my car has not sleepers since doing the upgrade either. I could see how MCU never sleeping could tax the 12V more especially if your battery is already gone through a lot of cycles. Wonder if it’s a bug or some setting that wasn’t applied when doing the upgrade. Hoping the issue gets fixed somehow, because I can’t figure how to get my MCU to sleep so far.

 

[EagleOne]

I had my 12V replaced at the same time doing the MCU2 upgrade, but my car has not sleepers since doing the upgrade either. I could see how MCU never sleeping could tax the 12V more especially if your battery is already gone through a lot of cycles. Wonder if it’s a bug or some setting that wasn’t applied when doing the upgrade. Hoping the issue gets fixed somehow, because I can’t figure how to get my MCU to sleep so far.

Hi dailo,

If you're confident that your car isn't sleeping and that none of the apps you may be using are keeping it awake, I suggest you get it in to the SC and have them diagnose and repair it. The loaner cars I've had over the past month are showing me what a properly sleeping car *should* be like. It's unnecessary power consumption (range reduction) and almost certainly a symptom of something potentially more serious with your car. Definitely something to address before the warranty runs out if it's not too late.

In my case it appears the sleeplessness has an underlying cause in a fault in the on board charging system.

 

[Shaz]

What a timely posting...just had my 2017 August build Model X upgrade to MCU 2 this past Tuesday...and today the car is bricked. No lights turning on when clicking the fob, door won't open.

I don't have any of those app (TeslaFi) connected to my car. Just a usb hard drive for dash cam.

I took delivery of this car September 2017 and have not received the warning of replacing the 12V battery.

Roadside assistance will be towing my car to the service center...will see what the reason is for this failure.

 

[VikH]

What a timely posting...just had my 2017 August build Model X upgrade to MCU 2 this past Tuesday...and today the car is bricked. No lights turning on when clicking the fob, door won't open.

I don't have any of those app (TeslaFi) connected to my car. Just a usb hard drive for dash cam.

I took delivery of this car September 2017 and have not received the warning of replacing the 12V battery.

Roadside assistance will be towing my car to the service center...will see what the reason is for this failure.

It is most likely the 12V. Keep us posted.

We may have a trend here.