Trying to learn more about my LX.
Is this what you are referring to - see photo.
So its function is to allow you to move the Gear Shift Lever.
Most cars will allow you to move that lever as long as you have turned the Ignition Switch.
I'm assuming that the Ignition Interlock is electrically controlled rather than mechanically controlled.
I checked the maintenance history at Lexus.com on my LX and it does have an instance
where the vehicle would not start and the battery had to be replaced. Perhaps that
plastic cover was removed then. I think I recall finding a black piece of plastic and
wondered what it was. Hope I did not throw it away.
View attachment 1280164