Did you ever get a fix? Was hoping new firmware update would help but doesn't look like there is any fixes for this issue.
Hi dailo,
As a matter of fact, I went to the SC this past Tuesday and spoke with the service manager along with their chief engineer and two other folks. They had worked with the California engineers and the long-awaited firmware fix was to be pushed down this week after which they wanted to monitor the car for a couple more days prior to releasing it.
They contacted me this morning and the firmware was pushed down today and they will monitor today and tomorrow and, if all remains stable, they'll drop the car off on Sunday morning. This fix should be whatever is presently being pushed out to the rest of the fleet starting today.
They appear to be confident that the 12V battery dying was caused by an interesting combination of things, foremost among these being the MCU upgrade - apparently this checked the 12V battery status in a manner that is inconsistent with the battery monitoring system that is in my car (HW 2.0). It was expecting the battery monitor system that is in the newer models. This is part of what the firmware is supposed to correct.
- There were a couple of items in the mix that I genuinely cannot repeat how they were interacting, but the long and short of it was that if my car was at the specified maximum charge level AND it was plugged in and... something else... this would generate a fault. The fault led the system to believe there was some issue with the 12V battery so the charging system would disengage. Normally the system can reset itself but the battery monitoring issue was apparently interfering with that and this led to the 12V battery NOT being recharged indefinitely until it just died. There are a couple of other things in this mix but the Firmware fix is supposed to allow the system to reset when the somewhat rare situation would present itself.
I get the sense there is still some uncertainty but they are hopeful that this is enough to resolve the issue. I get this feeling due to the provisions being made to ensure I don't get stuck again should the car brick itself again. i.e. I'm going to hang on to the loaner for a week or so until we're all satisfied the issue's been addressed.
The phantom drain issue is less certain. We disabled EVERYTHING that was talking to the car, even the Tesla App, by not only signing out of them explicitly (so they didn't give dumb readings on my smartphones) but also changing the password. Between the third party apps and my aftermarket Dashcam (DR750S-2CH) constantly pulling a bit of current they tell me it's VERY difficult to ascribe a cause. So I'm going to keep EVERYTHING disconnected and see what becomes of the phantom drain and then introduce each item one-by-one (again, I've done this before) to see when/if the drain resumes.
Frankly, I expect that if the car is finally able to sleep - and it's clear what this is like from the past 3 loaners I've had - I fully expect the phantom drain to minimize regardless of what goes on with the apps/dashcam. So I'll be looking for this first. If I find something that stops the car sleeping, I'll have my culprit. Almost certainly though, it will be a combination of things that will cause this it it happens at all..