[OperatorChan]

Not to beat a dead horse here, but like everyone above has already said, try replacing the 12v battery.

Also,

Change your fob keys batteries.
I had the message a few days before.

Mine did the same thing and it took a few days to go away after the batteries were changed

This would not cause the issues they're having. The worst that would happen from a low fob battery is a warning would come up on the Multi-function display.
You can still start your car with a dead fob battery actually, just hold the dead fob up to the start button and push it in using the fob.
Had a Lexus tech tell me about it after my fob casing split in half and all I recovered was the (thankfully intact) circuit board inside.

 

[OperatorChan]

Alright, If OP replaces his battery and fixes the issues I will eat my words.
I think the size you need is CR2032, but correct me if I am wrong.