2023 Prius Ltd. - Goes to Accessory Mode instead of Ready

So here's an interesting event that occurred and have wondered if this happened to anyone else.

Since I purchased the car (June 2023) it's been 50/50 if when I try to start the car for the first time in the day it either goes to Accessory or Ready Mode. I have/had a 2010 Prius and am doing all the standard things (Doors Closed, Break pedal pushed down, start button fully depressed, etc). I had initially chalked this up to some new safety interconnect such as not having the seat belt done, door closed to recently, starting too quickly once getting in, etc as it always* started the 2nd attempt and wasn't consistent on when it occurred or didn't occur.

That was all until Saturday when I attempted to start the car and again it went into accessory mode again, I turned the car off and back on and it still stayed in accessory mode with the screen saying depress brake pedal (It was fully depressed, I even let go and pressed again between the last 2 attempts) in total I tried to start the car 4 or 5 times before the battery just died on me. I took out a float charger and it showed the battery was at less then 25% charge, no lights were on and no accessories plugged in and it was last driven less then 36 hours before that so I do not understand how essentially the break pump could drain the battery dry in 4-5 attempts.

I took it to the dealership today for diagnosis but no codes were found, battery was tested in good health and they could find no explanation for the battery draining dry or for it not reliably entering Ready mode.

Wondering if anyone had any insights or had encountered this or something similar? I see a lot of comments on the 12V battery being a potential issue for a lot of people but not so much on the accessory mode issue (Unless it's related to the fact that the battery is drained too low to get to "ready" but putting it in accessory is enough to get HV system to supplement?)

 

From what I read most of the post were about the Prime in that thread but given that it's not just the charging that is at issue it might be something that affects the non-prime as well but couldn't find any mention of it failing to go into ready mode. Yes the brake lights do go on and the brake pump activates and provides resistance on the peddle when it is depressed prior to starting.

 

I suspect the battery as well but the only part that still makes me suspect is that if the battery was bad and it was starting in accessory mode then I don't see it starting the 2nd time into ready mode since accessory mode is not supposed to charge the 12V battery and even the fact of starting would drop the voltage further making the 2nd start unlikely to succeed. I do wonder if it's not perhaps a voltage issue but a load issue where the battery can no output enough current as opposed to voltage but a load test should show that too.