2022 Sienna Engine Battery Failure

Ok, posting this for a friend with a new 2022 Sienna hybrid but I also have a 2021 Sienna Hybrid sport.
The van was purchased summer of ‘22 and resides in Northern VT, I’m guessing between 5-10k miles at this point. There were several mornings in December where the van failed to start. I advised they bring it to the dealer where they were told there was a bad battery (12volt, not the hybrid batteries) and it was replaced. This morning the van wouldn’t start again. To me, who is not comfortable chasing electric gremlins, I advised they get it right back to the dealer asap.

While that is happening, I turn to the brain-trust that is TacomaWorld!
I assume there is a phantom electrical load drawing on the battery? I’ve always been suspicious of the secondary evap system that seems to pick the coldest nights to run for a suspiciously long time (at least in our Sienna). Has anyone encountered anything similar? I don’t believe there are any codes, but would a code reader help diagnose? I don’t believe they have done any aftermarket mods to the van. Any suggestions or advice is appreciated as Gremlins and Phantoms are not my specialty, nor should they be…this is on Toyota to resolve.
Additionally, we have had zero issues that were not self inflicted with our van at a trouble free 30k miles. Thanks in advance!

pic of our 2021 Sienna Sport

 

sure sounds like a phantom drain.... he's sure the kids aren't leaving the lights on or something? does he hav a multimeter?

 

I asked the same question…playing with the doors, charging items in the back, ski boot warmers…it doesn’t sound like it.

 

could be something like a bad ground.... multimeter is the next step if he wants to take a crack at it himself

 

@CTSpruceMica just brought this TSB to my attention, sounds possible…
https://www.toyoheadquarters.com/th...pleted-12v-vehicle-battery-t-sb-0016-21.2193/

 

wow, good find

let us know if you guys figure it out

 

It’s at the dealer, it sounds like they suspect slush on the auto door foot activated system? I guess it gets covered in ice and kinda freaks out? I’ll let you know when I hear more. All of the bout is appreciated.

 

@CTSpruceMica

OK, so it turns out that the dealer has decided it was the auto-opening door sensors getting covered in slush and freaking out. I’m not sure if I buy that as we have the same car, similar weather to Burlington (Saratoga area) and have had zero issues. I do think the auto doors are kinda dumb, an unnecessary technology that we have seen zero need for except maybe the tailgate. But guess what…adding a hitch receiver renders that sensor useless.
What ever…I’ll update if the problem persists. Thank you all who put eyes and brain power toward this, what a truly great community.

 

The things you wave your foot under to open the sliders? I'm not buying that either.

 

Yup…they say slush on them freaks them out and the computer just uses battery power trying to decide what to do. Sounds hokey to me.