Yeah, the wording was definitely not what I would have expected. That's why I spent way more time than I would have hoped digging through settings and trying different search terms while I was figuring this out for myself over a year ago when I got my GX.
From page 197 of the manual:
More interesting is why some owners have their ACC customization set to on vs off as a default when receiving the car. I found this in a Lexus PDS (pre-delivery service) document for the GX:
Customize ACC Function
The pre-startup function detects when a user enters the vehicle, and it energizes the audio head unit (+BA) so that the multimedia system can quickly be used. This function is not enabled at the factory to reduce parasitic current draw in transit and storage. To enable this function, it is necessary to set the ACC customization function in the navigation display to OFF.
1. Turn the engine switch (power switch) to the ON position (ON mode).
2. Enter the following menus: Settings – Vehicle Customization – Utility – ACC Customize.
3. Change the setting to OFF.
So it appears the cars come from the factory with ACC customize set to "on," and presumably anyone who has had it set to "off" without their own intervention was because their dealer followed this PDS sheet.
