Lexus RX300 (MCU15). Manual - part 392

I11572

Radio Receiver Assembly

Multi Display

Navigation ECU

Terminator

DI–798

–

DIAGNOSTICS

LEXUS NAVIGATION SYSTEM

LEXUS RX300   (RM785E)

AVC–LAN (Communication bus) Circuit

CIRCUIT DESCRIPTION

Each unit of navigation system connected with AVC–LAN (communication bus) transfers the signal of each
switch by communication.
When +B short and GND short occur in this AVC–LAN, navigation system will not function normally as the
communication is discontinued.
In this AVC–LAN, multi display becomes the master of the communication, and the radio receiver assembly
has a terminator necessary for transmitting the communication.
multi display is connected between navigation ECU and radio receiver assembly, navigation system has the
structure that makes communication impossible without navigation ECU, multi display or radio receiver as-
sembly.

AVC–LAN

DI84O–01

I19279

P–B

GR–R

W

TX1+

N4

5

I17
Instrument Control Panel

Radio and 
Player

C6
CD Automatic
Changer

Instrument Panel J/B

Stereo Component
Amplifier

Multi
Display

Navigation 
ECU

W

IN1

2

M4

5

TX1+

LHD Vehicle:

B–W

TX+

P–B

B

N4

10

B

IN1

11

M4

10

TX1–

TX1–

TX–

10

9

4

11

TX+

TX–

TX1+

TX1–

3

10

Y

M3

4

M3

11

TX3+

TX3–

TX+

TX–

M3

3

P

IK1

R–W

GR–R

16

(*1)

M3

10

R7

9

TX–

TX+

TX+

TX–

R7

10

R6

5

R6

15

P

S17

1

TX+

TX–

FL+

FL–

S15

20

P

BD1

2

P

LG

IK1

15

LG

S17

8

S15

9

V

BD1

11

P

(*2)

AUI+

AUI–

AUO–

AUO+

N3

1

N3

10

V

(*1)

V

(*2)

N3

11

N3

2

(*1)

B–Y

T9
Tweeter LH

1

(*1)

IA2

9

IA2

1

V

P

1D

4

1D

11

1F

1

V

1J

1

1J

3

1F

5

V

P

1

2

P

3

1C1

P

8 1C1

2

F14
Front Door Speaker LH

V

: AVC–LAN circuit

*1: w/ LEXUS Navigation System
*2: w/o LEXUS Navigation System

–

DIAGNOSTICS

LEXUS NAVIGATION SYSTEM

DI–799

LEXUS RX300   (RM785E)

WIRING DIAGRAM

I19280

P–B

GR–R

W

TX1+

N4

5

Instrument 
Control Panel

C6
CD Automatic
Changer

Multi
Display

W

IN1

2

M4

5

TX1+

RHD Vehicle:

B–W

TX+

P–B

B

N4

10

B

IN1

11

M4

10

TX1–

TX1–

TX–

10

9

TX+

TX–

TX1+

TX1–

3

Y

M3

4

M3

11

TX3+

TX3–

TX+

M3

3

Navigation 
ECU

(*1)

R–W

(*2)

M2

5

(*2)

M2

4

(*1)

I17

(*1)

10

I17

(*1)

7

I16

(*2)

11

I16

(*2)

4

I17

(*1)

6

I16

(*2)

11

I17

(*1)

10

I16

(*2)

O

TX–

M2

6

M3

10

M2

7

(*2)

(*1)

(*2)

(*1)

(*2)

(*1)

GR–R (*1)
W–R (*2)

Radio and 
Player

P

R5

1

TX–

TX+

TX+

TX–

R5

2

R6

5

R6

15

LG

R7

9

(*2)

(*1)

R7

10

(*2)

(*1)

P–B

O (*2)

(*1)

R4

9

R4

10

(*2)

(*1)

(*2)

(*1)

Stereo Component Amplifier

S17

1

TX+

FR+

FR–

S15

7

P

S17

8

S15

8

TX–

LG

L

LG

L (*4)

L (*3)

LG (*4)

LG (*3)

R–W

AUI+

AUI–

AUO–

AUO+

N3

1

N3

10

N3

11

N3

2

(*3)

B–Y

(*3)

15 IK1

16 IK1

2 BD1 11 BD1

IN1

1

IN1

10

B–Y

T10
Tweeter RH

1

2

3

4

L

LG

Instrument Panel J/B

1J

1

1F

1

1J

3

1F

5

L

IL1

8

IL1

3

L

LG

1

2

F15
Front Door Speaker RH

: AVC–LAN circuit

*1: Europe
*2: Except Europe
*3: w/ LEXUS Navigation System
*4: w/o LEXUS Navigation System

LG

DI–800

–

DIAGNOSTICS

LEXUS NAVIGATION SYSTEM

LEXUS RX300   (RM785E)

–

DIAGNOSTICS

LEXUS NAVIGATION SYSTEM

DI–801

LEXUS RX300   (RM785E)

INSPECTION PROCEDURE

1

Check wire harness and connector between radio receiver assembly and naviga-
tion ECU (See page IN–32).

NG

Repair or replace wire harness or connector be-
tween radio receiver assembly and navigation
ECU.

OK

2

Check wire harness and connector between multi display and navigation ECU
(See page IN–32).

NG

Repair or replace wire harness or connector be-
tween multi display and navigation ECU.

OK