Description & Operation: Notes

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.

NOTE: The multiplex control system may also be referred as In-Vehicle Multiplexing System (IVMS), or Local Area Network (LAN) system.

The multiplex control system uses a Body Control Module (BCM) and 5 Local Control Units (LCUs) to manage the following electrical systems: power window, power door lock, multi-remote control, theft warning, step light, rear power window switch illumination, interior light and ignition keyhole illumination, ignition key warning, headlight warning (buzzer), seat belt warning (buzzer), wiper amplifier, rear window defogger timer and self-diagnostic system. See COMPONENT LOCATIONS. Some electrical systems are directly connected to the BCM, while some switches and electrical loads and switches are connected to the appropriate LCU.

The BCM uses 2 data lines (A-1 and A-2) connected between BCM and LCUs to establish communication and control with each LCU. System has a sleep/wake-up control mode to turn on or shut off the communication between BCM and LCUs as necessary to prevent unnecessary power consumption. If BCM determines that a signal from an LCU is malfunctioning, system will set appropriate LCU in fail-safe control mode.