Hello,
There is a repeated problem of car showing every single possible error after turning it on. Dealer suspected it to be weak auxillary battery which was tested and replaced and every hybrid system connections were checked and reconnected. Also, there is no error code in car when this issue occurs.
I've been facing this issue since 4-5 months, but the frequency has now increased. First i could drive the car with error lights but as of now the car doesn't even start. I have to cycle start/stop 3-4 times for the Engine/Hybrid system to start. It mostly occurs after leaving the car overnight or driving it after 4-5 hours.
I'll give the car back to dealer and have asked them to escalate my problem to Lexus.

 

Glad they're taking care of you. That has to be an extremely frustrating problem, especially since we all know that bulletproof reliability is so central to the brand promise of a Lexus hybrid.

I can see why the dealer went there first. Lighting up the dash like a Christmas tree is a classic symptom of low battery voltage. It makes the CPU's get skittish.

Which makes me wonder if there's a small, chronic voltage leak somewhere in the car that's just insidiously draining the battery at all times. You can detect with instruments whether you're losing voltage somewhere, even before you can detect where it is. Unfortunately anything more specific than that is beyond my meager knowledge, but I suspect that's where the search begins.

One shot in the dark is at 18:30 of this video: a wireless modem in need of a software update. Unlikely I know, but we're hunting for a needle in a haystack here.