Description & Operation
WARNING: This page is about a different car, the 2000 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.
Body control system is used to monitor and control the functions of head, tail and interior lights, power windows, mirrors and door locks, trunk opener, theft deterrent horns (by means of multiplex communication with theft-deterrent ECU), and several other components. Body control ECU is interlinked on a multiplex communication network with theft-deterrent, driver's door, passenger's front door and power seat ECU. Before starting any diagnosis on body control system components or circuits, check multiplex system operation to ensure that all ECUs are able to communicate with each other. See MULTIPLEX CONTROL SYSTEMS - AVALON article.