Some progress it seems. I dropped my car off at a service center yesterday. Got to speak directly to the tech, he was so helpful and understanding. Came out to the car to discuss the battery drain issue and the parking assist not working.
I mention the “restraint control module” fix that another SC did that seemed to resolve the sleep issue (see my previous posts in this thread). He went into service mode in the car, said it’s unlikely to be the RCM as there isn’t any faults. But did say the the computer that does the driver assistance features was “shutdown”. Said that’s why “Park assist unavailable” warning was showing. And why cruise didn’t work, no driving visuals on the screen. Said that was very weird.
Tech called today and said they think it’s a signalling problem to the RCM. He confirmed the car was not sleeping at all. Which was such a relief to have the problem actually acknowledged instead of trying to tell me this is normal to lose 10% a day.
They don’t have the part so I’m booked for end of month for another service.
I’m still shocked it’s not software related as lots of people have this exact problem when they updated to 2023.20.4.1.
I hope the tech is right, will update when this is all finally resolved.
Tech’s notes incase this helps anyone else with a SC visit:
“Confirmed customer concern. Suspect internal short in RH BCM causing incorrect signal to RCM, causing the car not to sleep.. Will replace RH BCM next visit”