Multiplex Control Systems: Description

WARNING: Deactivate air bag system before performing any service operation. See appropriate 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.

CAUTION: Before disconnecting battery, obtain anti-theft code for radio. After battery is reconnected, the word CODE will appear on radio display. Enter 5-digit anti-theft code using select buttons and radio will begin working. If code is entered wrong 10 times, leave radio on at least one hour and enter code correctly. Any time radio power is lost, pre-selected radio stations will have to be set.

Multiplex control system consists of a driver, passenger, and door multiplex control units. These 3 control units integrate independent control units using multiplex communication lines. See Fig 1 .

Driver's multiplex control unit is located behind driver's side kick panel. Passenger's multiplex control unit is located behind passenger's side kick panel. Door multiplex control unit is located in driver's door and is incorporated in power window master switch.

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

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

Fig 1: Locating Multiplex Control System Components (3.2TL)

Courtesy of AMERICAN HONDA MOTOR CO., INC.