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MCU Slow Boot and Car Unresponsive via App

boelkers

Member
May 30, 2017
131
119
Minnesota
I've had this issue happen twice now. First time I thought it was perhaps a fluke. 2nd time not so much. Heres the story.
I parked my MX in the garage like normal and plugged it in for the night. Charging is supposed to start at 12:00am. Woke up the next morning to turn on the heater about 15 mins before I leave the house. I tried accessing my car via the App, the app connected to the car but shows no battery and ---%. See Attached screenshot. The car is also in an unlocked state. Turn on heater and see the air flow arrows but no temp or color changes showing that the heat was on.

I go out to my MX and unplug the car and get in. Heat did not turn on and the MCU is off and not turning on. Try the reset but that does not work. Try it again, still no go. Wait in car 5 mins and the screen finally turns on by itself. Look at charge level and see that the car did not charge at all last night. Put in bug report after boot so if a technician worked on it they would see the timestamped area in the logs.
This happened a second time about 5 days later. After this happened for the second time I called Tesla to see what was going on.

Speaking with a tech, he connected to my car and saw that the firmware was good and saw no issues in the logs. But then asked what both my trip meter mileage was. Well Trip A had 16K and Trip B had 18K. Trip B for me is the "Lifetime" miles I've personally driven the car since. My MX was a demo vehicle and had 2K miles on it already so the odometer isn't exact for my personal usage. The tech stated that those are really high numbers explained that when the logs get full the car deletes old records, but it cannot delete everything it needs to if the trip meters are not also being reset on a regular basis. He said I was essentially filling my logs and the car was unable to delete certain data.

I don't know how accurate his statements were but I reset them anyway. So far I've not had the issue again but I'll be calling back if it does. If this does resolve my issue in the long term then I hope this info can help someone else if they experience the same issue.
 

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FTNguyen

Member
Aug 31, 2016
8
12
Denver, CO
I had a 40K lifetime trip, MCU was rebooting almost daily and door screen took 5-6 seconds to respond after putting car in park. Took it to serivce center they suggested resetting that trip and it seemed to fix all my issues. It's been almost 2 weeks and haven't had an had a reboot since.

I was also skeptical of this 'Fix' at first.
 

AdamHLG

Member
Sep 29, 2017
326
469
Baltimore, Maryland
So my car is getting a Modesta coating at a shop 90 minutes away from me. Dropped it off earlier this week and I pick it up tomorrow. Last night I was playing on my computer waiting for my wife and decided to check Teslafi and see the sleep cycle and charge on the car. To my surprise I received some sort of error where the data should be on the Teslafi page and was like 'wtf'. So I launched the app and saw the empty battery and the ---% and was like "HOLY %$$#" and thought my battery must be dead. It was after hours of course so the shop was not open. I sent a frantic email and he responded that he thought everything was OK but the MCU was very slow to start. He indicated he had seen it before and would try a reset on the car this morning (not the 'trip reset' but I guess a MCU reset).

Then I found this thread and felt MUCH better overnight. So kudos to the OP (wait - that is you that just posted OP lolol) because he posted the exact issue and I assumed my battery was not actually dead! This morning I checked the app and my baby was alive again with 176 miles of range. And...... exhale!!!!!

I don't know which reset he tried but he emailed me and said the reset worked. We will see if it holds. If not I will reset the Trip counters because, I too use one of those to measure my "date of delivery" data. But I only have 6,000 miles so far.
 

Logger

Member
May 11, 2017
61
27
American Southeast
I've had this issue happen twice now. First time I thought it was perhaps a fluke. 2nd time not so much. Heres the story.
I parked my MX in the garage like normal and plugged it in for the night. Charging is supposed to start at 12:00am. Woke up the next morning to turn on the heater about 15 mins before I leave the house. I tried accessing my car via the App, the app connected to the car but shows no battery and ---%. See Attached screenshot. The car is also in an unlocked state. Turn on heater and see the air flow arrows but no temp or color changes showing that the heat was on.

I go out to my MX and unplug the car and get in. Heat did not turn on and the MCU is off and not turning on. Try the reset but that does not work. Try it again, still no go. Wait in car 5 mins and the screen finally turns on by itself. Look at charge level and see that the car did not charge at all last night. Put in bug report after boot so if a technician worked on it they would see the timestamped area in the logs.
This happened a second time about 5 days later. After this happened for the second time I called Tesla to see what was going on.

Speaking with a tech, he connected to my car and saw that the firmware was good and saw no issues in the logs. But then asked what both my trip meter mileage was. Well Trip A had 16K and Trip B had 18K. Trip B for me is the "Lifetime" miles I've personally driven the car since. My MX was a demo vehicle and had 2K miles on it already so the odometer isn't exact for my personal usage. The tech stated that those are really high numbers explained that when the logs get full the car deletes old records, but it cannot delete everything it needs to if the trip meters are not also being reset on a regular basis. He said I was essentially filling my logs and the car was unable to delete certain data.

I don't know how accurate his statements were but I reset them anyway. So far I've not had the issue again but I'll be calling back if it does. If this does resolve my issue in the long term then I hope this info can help someone else if they experience the same issue.

I had something similar happen twice. Once in October, the MCU shut down after charging had started and basically did not stop charging at the set level so instead of 80% I had a 95% battery when I woke up and manually stopped it. Most recently, this morning, the MCU went down before charging started so this morning I had only 80 miles on the battery. I took the car in back in December and they reset the trip meters. I thought this was a very interesting thing but okay they said it would need to be done, but my question is how often? I only have around 4000 miles on the trip meters now. Is this something I should do every month? If so I think there needs to be some updates being made to resolve it. Just my opinion.
 

Joelhc

Member
Oct 10, 2018
35
4
Los Angeles, CA
I also have this issue with the car waking up via the app and used to have the problem with the car being asleep and having to wait for it to wake up when entering. The latter seems to be less common now though. I don't seem to have any power saving options that other people talk about like "always connected". Maybe that was removed in the recent updates, I've only had the car for 6 weeks.
 

jboy210

Supporting Member
Supporting Member
Dec 2, 2016
5,384
3,338
Northern California
I also have this issue with the car waking up via the app and used to have the problem with the car being asleep and having to wait for it to wake up when entering. The latter seems to be less common now though. I don't seem to have any power saving options that other people talk about like "always connected". Maybe that was removed in the recent updates, I've only had the car for 6 weeks.

From what I understand, some setting were removed as part of the MCU2 upgrade found in cars manufactured after mid-March 2018.
 

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