Q45t V8-4130cc 4.1L DOHC MFI (VH41) (1997)
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Information Bus: Description and Operation
IVMS (LAN) System
OUTLINE
The In-Vehicle Multiplexing System, IVMS (LAN system), consists of a BCM (Body Control Module) and five LCUs (Local Control Units).
Some switches and electrical loads are connected to each LCU. Some electrical systems are directly connected to the BCM. Control of each LCU,
(which is provided by a switch and electrical load), is accomplished by the BCM, via multiplex data lines (A-1, A-2 or A-3) connected between
them.
BCM (Body Control Module)
The BCM, which is a master unit of the IVMS (LAN), consists of microprocessor, memory and communication LSI sections and has
communication and control functions. It receives data signals from the LCUs and sends electrical load data signals to them.
LCU (Local Control Unit)
The LCUs, which are slave units of the BCM, have only a communication function and consist of communication LSI and input-output interface
circuits. They receive data signals from the BCM, control the ON/OFF operations of electrical loads and the sleep operation, as well as send
switch signals to the BCM.
CONTROLLED SYSTEMS
The IVMS controls several body-electrical systems. The systems included in the IVMS are as follows:
^
Power window
^
Power door lock
^
Multi-remote control system
^
Theft warning system
^
Interior illumination control system
^
Step lamp
^
Illumination (Power window switch illumination)
^
Auto drive positioner
^
Auto light.
^
Door open warning.
^
Ignition key warning.
^
Light warning.
^
Seat belt warning.
^
Wiper amp.
^
Rear window defogger timer.
^
Trouble-diagnosing system
- with CONSULT
- ON-BOARD
Also, IVMS has the "sleep/wake-up control" function. IVMS puts itself (the whole IVMS system) to sleep under certain conditions to prevent
unnecessary power consumption. Then, when a certain input is detected, the system wakes itself up. For more detailed information, refer to
"Sleep/Wake-up Control".
Sleep Control
SLEEP/WAKE-UP CONTROL
"Sleep" control prevents unnecessary power consumption. After the following conditions are met, the BCM suspends the communication between
itself and all LCU's. The whole IVMS is set in the "sleep" mode.
^
Ignition switch "OFF"
^
All electrical loads (in the IVMS) "OFF"
^
Timer "OFF"
