Description & Operation
WARNING:
Deactivate air bag system before performing any service operation. See AIR BAG RESTRAINT SYSTEMS article. DO NOT apply electrical power to any component on steering column without first deactivating air bag system. Air bag may deploy.
The multiplex control system consists of a body Electronic Control Unit (ECU), power seat ECU, remote control mirror ECU, tilt and telescopic ECU, and related wiring (communication bus). See Fig 1. Some electrical systems are directly connected to the body ECU, while some electrical loads and switches are connected to the appropriate ECU. The multiplex control system is also equipped with a self-diagnostic function. The communication bus is self-diagnosed by the body ECU which stores an appropriate Diagnostic Trouble Code (DTC) if a fault is detected.
NOTE:
The body ECU is also referred to as instrument ECU or instrument panel ECU.