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2018 P100D Unable to drive and screen not working, but lights and doors open. Had 12V replaced 2 months ago and MCU2 infotainment upgrade last year

turtlesz

Member
Aug 7, 2017
520
467
Southern California
Sadly woke up yesterday and our Tesla yet again failed to work. Have had 2 drive unit failures on our LR 3 in the past 3 years, a dead 12v recently on our X and now this issue as the major problems. Love the cars when they are working but confidence in them from a reliability standpoint is down the drain. Its a 2018 P100D X and I'm unable to shift it into to drive and the screen is not working, but the lights turn on and doors open, horn doesn't work. Had the 12V battery replaced 2 months ago and MCU2 infotainment upgrade done last year. I tried the scroll wheel reset multiple times, took out all USB devices. The car doesn't charge but I' m able to put the charge port and put in the cable and see a solid blue light. I did supercharge the car the day before it stopped working. Could a MCU2 failure cause the car to be unable to drive? It will be towed to a nearby service center, just a huge inconvenience since we had a trip planned and have babies. Any ideas what could be going on?
 

Les236

Member
Jan 20, 2018
157
87
Kissimmee, FL, Boston, MA
I hate reading all of these posts. I have yet to have my 12v changed on my 3/2018 MX100D, and too have a trip planned in 30 days. I have not had the problems you are having. I do believe you can drive without the MCU2 as I have had to reboot while driving a couple of times. Wondering if I should replace the 12v on a preemptive basis or wait for a message.
 

turtlesz

Member
Aug 7, 2017
520
467
Southern California
I hate reading all of these posts. I have yet to have my 12v changed on my 3/2018 MX100D, and too have a trip planned in 30 days. I have not had the problems you are having. I do believe you can drive without the MCU2 as I have had to reboot while driving a couple of times. Wondering if I should replace the 12v on a preemptive basis or wait for a message.
Mine was built in 03/2018 also, the 12V issue is pretty scary. Maybe reading how to jump the car and having a portable battery jumpstart device is a good idea, not sure if preemptively changing the 12v is needed. Luckily mine failed in the garage at home and not when I was out. Since we have kids now, these issues on determining if the car will work or not is unacceptable. Our 3 failed when we were 400 miles away from home, but that was before babies so we could make due with a loaner and the inconvenience.
 

Les236

Member
Jan 20, 2018
157
87
Kissimmee, FL, Boston, MA
I do have one of the portable jumper packs in the frunk, mostly to assist stranded ICE drivers but also as a backup should the 12V die. Did you have any warnings before it went? My MCU2 upgrade was done around October last year and no issues. Unfortunately because of Covid it sits in the garage about 5 days a week and I don't keep it plugged in. Because of my travels, it also sits for 30-50 days sometimes, but I do keep it plugged in now as the vampire drain is so much these days.
 

ShawnA

Supporting Member
Nov 13, 2017
906
666
Edwardsburg, MI
Hi @turtlesz ,

If you have a solid blue ring for charging that means you have charging scheduled by TIME or DEPARTURE.
Turn that off if you can...

You are supposed to be able to drive with a dead MCU, but it is not pleasant...

Good luck,

Shawn
 

turtlesz

Member
Aug 7, 2017
520
467
Southern California
Hi @turtlesz ,

If you have a solid blue ring for charging that means you have charging scheduled by TIME or DEPARTURE.
Turn that off if you can...

You are supposed to be able to drive with a dead MCU, but it is not pleasant...

Good luck,

Shawn
I know with a dead MCU1 you could still drive, is that the case for MCU2 also? I do have scheduled departure but I plugged it in during the scheduled charge time and it didn't charge. I was able to open and close the charge port from the app but unable to pick charge immediately. Car is at the service center now, so hopefully I get an answer as to what is happening.
 

VikH

Supporting Member
Nov 23, 2015
965
780
Midwest, USA
I know with a dead MCU1 you could still drive, is that the case for MCU2 also? I do have scheduled departure but I plugged it in during the scheduled charge time and it didn't charge. I was able to open and close the charge port from the app but unable to pick charge immediately. Car is at the service center now, so hopefully I get an answer as to what is happening.
Sounds like a dead MCU2 based on the inability to charge and screens not working. MCU2 runs both the binnacle and the main screen, whearas MCU1 binnacle can run separately from main screen.
 

scottf200

Active Member
Feb 3, 2013
3,831
3,406
Chicagoland ModelX S603
I hate reading all of these posts. I have yet to have my 12v changed on my 3/2018 MX100D, and too have a trip planned in 30 days. I have not had the problems you are having. I do believe you can drive without the MCU2 as I have had to reboot while driving a couple of times. Wondering if I should replace the 12v on a preemptive basis or wait for a message.
I tried to be preemptive with my 12v using a IR (internal resistance) meter as well as keeping a 12v battery monitor on it (threads on this) ...
then I had a 12v issue while one a road trip and had to deal with it. Not fun; not cool. Now I'm a firm believer in changing the 12v every 2.5 years. Cheap to buy and install yourself or have the service center do it. Some info here: I monitored the 12v battery voltage during an OTA update

Sounds like a dead MCU2 based on the inability to charge and screens not working. MCU2 runs both the binnacle and the main screen, whearas MCU1 binnacle can run separately from main screen.
I'm very sorry to read about your opening post several troubles. If you are moderately handy with minor tools you can disconnect the 12v for a few minutes to reset the car. Info in this post and thread: P100D X 12V battery dying in a car without any warning? and this post P100D X 12V battery dying in a car without any warning?
 

turtlesz

Member
Aug 7, 2017
520
467
Southern California
Car was fixed. They wrote "internal electrical fault rear drive unit. Drained and filled cooling system. Replaced large drive unit rear gearbox fluid. Replaced large (includes alignment) read drive unit. Performed firm ware and coolant purged." Glad it was fixed but still concerned I've had so many failures between our 3 and X.
 

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