Did you replace the 12v with one from Tesla or some 3rd party brand?   Many
12v batteries now are made with garbage lead that isn't refined well, so
ends up with a short life.  Do you have any accessories hooked to the 12v
system?   If you tap the 12v battery for anything this can be the result.
 If you use the OEM Atlas battery it shouldl last from 3-5 years depending
on climate and your drive cycle.

VCFRONT measures the amp-hour capacity of the 12v battery and will set that
alert when it detects capacity is insufficient to allow sleep, and it will
then disable sleep so you don't end up with a dead car.   If you want to
double-verify this, you can reset the amp-hour counter by disconnecting the
12v battery, then the HV, then reconnect both.  The alert will go away, It
will then re-measure the capacity and the alert will return if it's still
too low.

FYI: The high-quality 12v battery made by Atlas is only $100 at any Tesla
service center. (Down in cost!)   Part # 1129182-00-B.  You can walk in and
grab one off-the shelf.

Here's my video on the 12v system that explains more:
https://www.youtube.com/watch?v=i27lApNWkyA

On Sun, Nov 30, 2025 at 12:29 PM Mark Hanson via EV <[email protected]>
wrote:

> Hi Folks
> The Tesla Y 2021 did another (almost daily unnecessary) update and now
> displays a “VCfront a402 Electrical system backup power is unavailable.
> Vehicle will consume more energy while idle.  Software will not update”.
> Then expanding to: “VCfront a192 electrical system is unable to support
> all features. VCfront a182 schedule service to replace low voltage battery.
> Software will not update”.
>
>   But then displayed updated software minor fixes.  The pricy 12V battery
> (due to the non standard size), I replaced 6 months ago.
> Do I just ignore this silliness?  Is there a way to reset these screen
> messages?
> Go back to a previous “update”?
> Best regards Mark in Roanoke Va
> Sent from my iPhone
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