AVC-LAN Circuit: Description
WARNING: This page is about a different car, the 2008 Lexus LS 600hL. However, it is still accessible from the selected car via links, so may be relevant.
Each unit of the audio and visual system connected to AVC-LAN (communication bus) communicates by transferring the signals from each switch
When a short to +B or short to ground occurs in this AVC-LAN, the audio and visual system will not function normally as the communication is discontinued