Lexus RX300 (MCU15). Service manual — part 60

BE

BODY ELECTRICAL — MULTIPLEX COMMUNICATION SYSTEM

BODY ELECTRICAL

113

MULTIPLEX COMMUNICATION SYSTEM

JDESCRIPTION

D A multiplex communication system has been adopted for body electrical system control and to achieve

a slimmer wiring harnesses configuration.

D The BEAN (Body Electronics Area Network) has been adopted between the body ECU, engine ECU,

air conditioner and combination meter integrated ECU, theft deterrent ECU, double lock ECU, driver
door ECU, front passenger door ECU, rear RH door ECU, rear LH door ECU, moon roof control ECU,
and center cluster integration panel ECU. Furthermore, AVC-LAN (Audio Visual Communication-Local
Area Network) has been adopted between the center cluster integration panel ECU, multi display, audio
unit, CD automatic changer, and navigation ECU.
The conversion of communication signals between BEAN and AVC-LAN is performed by the center
cluster integration panel ECU.

D A customized body electronics system, which improves the malfunction diagnostic function, enables

the functions to be changed according to customer needs, and reduce the types of parts, has been adopted.

" System Diagram A

187BE19

: BEAN
: AVC-LAN

Front Passenger

Door ECU

Rear RH

Door ECU

Engine ECU

A/C and

Combination

Meter Integrated

ECU

Theft Deterrent

ECU

Double Lock ECU

Body ECU

Moon Roof

Control ECU*

1

Center Cluster

Integrated Panel

ECU

CD Automatic

Changer*

2

Multi Display

Navigation

ECU*

3

Audio Unit

Driver Door

ECU

Rear LH

Door ECU

*

1

: with Moon Roof

*

2

: with CD Automatic Changer

*

3

: with GPS Voice Navigation System

BODY ELECTRICAL — MULTIPLEX COMMUNICATION SYSTEM

114

JSYSTEM OPERATION

1. General

The ECUs that pertain to the body electrical system perform the functions and system controls described
in the following chart.

ECUs

Function and System Control

Body ECU

• Wireless door lock remote control system control

• Door lock system control

• Illuminated entry system control

• Automatic light control system control

• Light automatic turn-off system control

• Daytime running light system control

• Key reminder system control

• Seat belt warning light control (for Driver’s Side)

• Rear wiper control

• Customized body electronics function

• Front and rear fog light control

• Diagnosis

Engine ECU

• Engine control

• Diagnosis

Theft Deterrent ECU

Theft deterrent system control

Double Lock ECU

Double locking system control

A/C and Commbina-
tion Meter Integrated
ECU

• Meter control

• Illuminated and flashing control of indicator and warning light

• Air conditioner control

Moon Roof Control
ECU

Moon roof control

Center Cluster Integra-
tion Panel ECU

• Conversion of data between BEAN and AVC-LAN

• Transmission of vehicle information to the multi display assembly, in

order for it to be displayed on multi-information display

Driver Door ECU

Power window system control (All door)

Front Passenger Door
ECU

Power window system control (Front passenger door only)

Rear RH Door ECU

Power window system control (Rear RH door only)

Rear LH Door ECU

Power window system control (Rear LH door only)

BE

BODY ELECTRICAL — MULTIPLEX COMMUNICATION SYSTEM

115

2. Customized Body Electronics System

General

The customized body electronics system can change the specification of functions (by changing their set-
tings) according to customer preferences by a hand-held tester to overwrite the EEPROM that is enclosed
in the body ECU.

" System Diagram A

187BE20

Software

Card

Hand-Held
Tester

DLC3

Body ECU

Tool Connecting
Circuit

EEPROM

Automatic Light

Control System

Wireless Door Lock
Remote Control System

Reminder System

Illuminated Entry

System

BEAN

Driver Door ECU

Moon Roof Control

ECU

Power Window

System

Moon Roof System

Operation

The specifications of the systems and functions that can be changed by operating a hand-held tester are
listed below.

System

Content

Initial Setting

Setting

Wireless
D

L

k

Wireless Operation

Permission

Permission/

Prohibition

Door Lock
Remote Control
System

Time Until the Operation of the
Automatic Lock Function

30 sec.

60/30 sec.

System

Interior Light Function

ON

ON/OFF

Automatic Light
Control System

Sensitivity Adjustment

0

–40/–20/0/+20/+40 (%)

Reminder System

Light Reminder Function

ON

ON/OFF

Illuminated
Entry System

Interior lights illuminate when
the doors are unlocked by the
operation of the door key.

ON

ON/OFF

Entry System

Interior Light Illumination Time

15 sec.

7.5/15/30 sec.

Power Window

Key-linked Open Operation

ON

ON/OFF

System

Key-linked Close Operation

ON

ON/OFF

Key-linked Open Operation

ON

ON/OFF

Key-linked Close Operation

ON

ON/OFF

Moon Roof

Key-linked Operation Selection

Slide

Slide/Tilt

Transmitter Operation Linked
Operation Selection

Slide

Slide/Tilt

BODY ELECTRICAL — LIGHTING

116

LIGHTING

JHEADLIGHT

The RX300 has adopted the wave-reflector headlights.
Conventional headlights accomplish the dispersion and distribution of the light that is emitted by the bulbs
through the lens cut pattern. However, with the wave-reflector type headlights, the light from the bulbs
is dispersed and distributed through wave parabolic shaped reflectors. As a result, the lens cut pattern is
no longer provided in the center of the lens, thus realizing a clear look.

" Light Distribution Imaginary Diagram A

151LBE68

Reflector
(Wave Parabolic Shape)

Headlight Bulb

Lens

Light Distribution

Light Distribution

187BE46

Wave-Reflector Type Headlight

Reflector
(Rotating Parabolic Shape)

Lens Cut

Conventional Headlight

Lens

Headlight Bulb

JFRONT FOG LIGHT

The projector light used for the front fog lights has the bulb located at one of the two focal points (No.
1 focus) while the beam collected at the other focal point (No. 2 focus) by the oval-shaped reflector reflects
the light, projecting it forward to the projection lens. With this type of light, the effective usage range of
the incident beam striking the upper reflector is wide and ensures a sufficient level of light. Compared
to the ordinary semi-sealed beam type lamp, this type can be made more compact and since the beam from
the source of light is concentrated in a narrower range, the amount of light leaking away from the direction
of projection is small.

" Imaginary Diagram A

187BE07

Projector Lens

No. 2 Focus

Reflector

Bulb

No. 1 Focus

Shade

Lens

Side View

Projector Lens

Reflector

Bulb

Lens

Top View

Cross Section