I have searched the internet and I'm not sure this "ACC Customize" toggle switch is explained very well. I figured I'd share my experience in the event it helps others.

In the 2024 LS this option is in Settings (gear icon) -> Vehicle Customize -> Utility

The default is that this is toggled on. With ACC Customize "ON" this appears to do 2 things..... 1) when you turn the car off, the radio immediately turns off. 2) When using the push button start, this enables Accessory Mode (foot off brake, first START/STOP button push = Accessory mode, 2nd START/STOP button push = ON). Of course if you put your foot on the brake, any push of the START/STOP button will start the engine.

I initially didn't like that the radio turns off when I shut off the car. Other vehicles I have the radio stays on until I open the door. I want this in my Lexus.

So I discovered that if you turn ACC Customize to OFF, then the radio will keep running after you turn the car off. But, the downside..... this same switch setting also eliminates the Accessory Mode key switch. Meaning when you set ACC Customize to OFF, have your foot off the brake, and press the START/STOP button, the first press of START/STOP = ON mode. Accessory Mode is apparently eliminated.

Its a bit unfortunate because I like the feature of the radio staying on when I shut the car off. But the downside is that if you get into the car and just want to turn on the radio without starting the car (use Accessory Mode), you hit the START/STOP with your foot off the brake and absolutely everything turns on. Dash, lights, everything but the engine.

If Toyota/Lexus is open to suggestions, please make an option to keep the radio on after shutdown while also keeping Accessory Mode enabled.

 

This has been bugging me since I bought my LS500 in August. Thanks!