Description & Operation

NOTE: This article covers procedures for body control system as well as driver door control system, passenger door control system and back door control system. The back door control system is for the rear liftgate.

WARNING: Vehicle is equipped with air bag supplemental restraint system. Before attempting ANY repairs involving steering column, instrument panel or related components, see SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM in appropriate AIR BAG RESTRAINT SYSTEMS article.

Body control system controls the following systems: power door locks, anti-theft system, keyless entry system, back (rear liftgate) door rear wiper/washer system and lighting control system. Body Electronic Control Unit (ECU) is connected to a multiplex communication system with driver's door ECU, passenger's door ECU, back door ECU, meter ECU and sliding roof ECU. This communication system is referred to as the multiplex control system. Before starting any diagnosis on body control system components or circuits, check multiplex control system operation to ensure that all ECUs are able to communicate with each other. See MULTIPLEX CONTROL SYSTEMS - SEQUOIA article.

Driver door and passenger door control systems are used to control the following systems on each respective door: power window, door courtesy light and key related functions. Driver's door Electronic Control Unit (ECU) and passenger's door ECU is connected to a multiplex communication network with body ECU, back door ECU, meter ECU and sliding roof ECU. This communication system is referred to as the multiplex control system. Before starting any diagnosis on driver door or passenger door control system components or circuits, check multiplex control system operation to ensure that all ECUs are able to communicate with each other. See MULTIPLEX CONTROL SYSTEMS - SEQUOIA article.

Back door control system is used to control the following systems on rear liftgate door: power window, back door lock, luggage compartment light and rear wiper/washer system. Back door Electronic Control Unit (ECU) is connected to a multiplex communication network with body ECU, driver's door ECU, passenger's door ECU, meter ECU and sliding roof ECU. This communication system is referred to as the multiplex control system. Before starting any diagnosis on back door control system components or circuits, check multiplex control system operation to ensure that all ECUs are able to communicate with each other. See MULTIPLEX CONTROL SYSTEMS - SEQUOIA article.