Frozen Forward in Time

While the MCU continues to suffer from lock-ups, I have noticed recently that it's been coming back to life at the time shown on the screen. Today I looked at my watch while it was frozen, and the Tesla actually showed a time in the future: actually, the time at which it was going to once again become responsive.

While I've got limited resources to debug or verify the problem, short of doing what wk057 did, this could indicate an issue with the real-time clock (RTC). The RTC is the system that is supposed to keep accurate time when the car is powered off, using its own dedicated power source. When the car's computer, like your PC, turns on, it loads the time stored from the RTC and uses that to know what time it is. Normally, a computer will then check to see what the correct time is with time servers on the Internet (the the computer in a Tesla car may use the network time protocol like a standard computer, query the LTE modem to get the time from the telecom carrier, or both; I'm not sure what it tires to do). The computer then is responsible for keeping its own time while running, and for updating the RTC if it realize it's not the right time.

The theory would be that the RTC is running fast, so when the car brings its modem online and gets the updated time, it realizes it has the wrong time, and retards (or halts) the clock until the difference ("skew") is resolved. If the MCU's interface is relying on the real-world clock as part of its timing loop, it essentially pauses until the clock reaches the correct time.

Annoyingly, in this case I couldn't close the garage door from the car. In addition to the non-responsive UI, the system didn't recognize that we had reached the auto-closing distance in order to trigger the door closing. The two redeeming factors were 1) at least I knew when the car would start responding, and 2) other people were home, so I didn't actually need to close the door this time.