Toyota Lexusc Owner's Handbook Manual page 366

AUDIO
(a) Before using the controller (for new vehicle owners)
2. Remove the insulating sheet.
A battery is already set in the controller with an insulating
sheet, which prevents the battery from being discharged.
Before using the controller, remove the insulating sheet
according to the following procedure.
To remove the insulating sheet:
1. Remove the cover of the controller as shown.
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