Component Tests and General Diagnostics

CIRCUIT DESCRIPTION
Each unit of LEXUS navigation system connected with AVC-LAN (communication bus) transfers the signal of each switch by communication.
In the case that this AVC-LAN has +B short and GND, LEXUS navigation system will not function normally as the communication is discontinued.
In this AVC-LAN, Navigation ECU, becomes the master of the communication, and the audio head unit has a resistance necessary for transmitting the communication.
Display ECU is connected between them, It has the structure that makes communication impossible without Navigation ECU, Display ECU or Audio head unit.





AVC-LAN




WIRING DIAGRAM

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INSPECTION PROCEDURE