To add to the conversation, here's a JEDEC presentation on how temperature affects data retention in solid state hard drives:
https://www.jedec.org/sites/default/files/Alvin_Cox [Compatibility Mode]_0.pdf
Page 27 has a neat chart that shows retention of data drops as the powered-off temperature rises. As long as the chip is actively powered and at reasonably warm temps though, retention is at its highest. I'm not sure how this correlates to eMMC, but I can only imagine it's similar.
To shift gears for a minute, I'm very interested in pulling the trigger on doing a preventative eMMC replacement with you, but I have concerns that I have not been able to find an answer for.
I'm assuming the eMMC contains a lot of private data (GPS locations, personal identifiers/tokens with Tesla, etc.) that I don't want getting into the wrong hands. Granted, I can do a master reset to wipe the data, but I'm also assuming that just zeros out the partition table and the data is still available to pull using ddrescure or any other standard data recovery method once you have physical connectivity to the chip.
What is your stance on data privacy? Again, I want to send my board to you for preventative repair, but I need written commitment that my data is treated as confidential, only pulled to copy directly to the new chip, that all backups are deleted after the job is finished, and that you agree not to distribute my data in any form what-so-ever.
I'd also like to see a statement on any modifications you're making to the operating system since I know Electrified Garage advertises they root the OS and enable remote access (they don't say if it's just SSH or something else). I don't wish for anyone other than Tesla and myself to have access to my car remotely.