Multiplex Control Systems: Description

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.

Multiplex control system consists of door, driver and passenger multiplex control units. If vehicle is equipped with Driving Position Memory System (DPMS), a driver's power seat control unit is also included in multiplex system. These control units are integrated with each other using multiplex communication lines. See Figure . For more diagnostic information on DPMS, see DRIVER'S POSITION MEMORY SYSTEMS - MDX article.

Multiplex control system includes a multiplex function, a wake-up/sleep function, fail-safe function, and a 2-mode self-diagnostic function. Self-diagnostic mode 1 is used to diagnose multiplex control system. Self-diagnostic mode 2 is used to diagnose a failure in input line of each system.

Multiplex control system includes engine oil pressure indicator circuit, seat belt reminder circuit, lights-on and key-in reminder, and key light timer circuits. Other controlled systems include dash illumination brightness control, entry illumination, automatic lights off system, power door locks, power windows and moon roof (with key-off timer operation), wiper/washers (with speed respondent intermittent wiper), security alarm system, interlock system and memory seat and mirror control.