Lexus RX300 (MCU15). Manual - part 364

DI3JR–02

I21406

Rear Left and Right Door ECU

Driver and Passenger Door ECU

Body ECU

A/C and Combination Meter Integrated ECU

Center Cluster Integration Panel

Engine & ECT ECU

MPX1

MPX2

MPX+

MPX–

MPX2

MPX1

MPX1

MPX2

MPX1

MPX2

MPX+

MPX–

Except Europe

Europe

MPX–

MPX+

DI–686

–

DIAGNOSTICS

MULTIPLEX COMMUNICATION SYSTEM

LEXUS RX300   (RM785E)

TERMINALS OF ECU

I19182

Teft Deterrent ECU

Sliding Roof ECU

MPX1

MPX1

Double Lock 
Control Relay

MPX2

MPX1

MPX2

–

DIAGNOSTICS

MULTIPLEX COMMUNICATION SYSTEM

DI–687

LEXUS RX300   (RM785E)

DI84Y–01

I19268

Front Passenger
Door ECU

MPX1

MPX2

10

F17

11

F17

Y–R

IL1

5

Y–R

IM1

3

Y–R

BB1

11

BB1

10

Y–R

R16

4

R16

5

Rear Right
Door ECU

MPX2

MPX1

W

Y

D11

10

D11

9

W

Double Lock Door

Control Relay

MPX2

MPX1

BD1

4

W

BA1

10

W

R14

4

MPX2

MPX1

R14

5

Rear Left
Door ECU

D12

11

Driver Door
ECU

MPX2

MPX1

D12

10

BA1

11

V

IA2

11

V

IC1

10

IC1

5

Y–R

Y–R

B–O

T5

8

T5

7

MPX1

MPX2

Theft Deterrent ECU

Y–B

IE1

4

Y–R

C12

21

C12

17

Combination
Meter ECU

MPX+

MPX–

Y–B

I17

5

I17

12

Instrument Control
Panel

MPX+

MPX–

Body ECU

MPX1

MPX2

11

B5

20

B8

LHD Vehicle:

W–R

Engine and 
ECT ECU

Y

W–R

MPX1

MPX2

18

E9

11

E9

10 IL1

Y

W–R

7

W–R

ID1

M6

2

Sliding Roof
Control ECU

MPX1

V

V

DI–688

–

DIAGNOSTICS

MULTIPLEX COMMUNICATION SYSTEM

LEXUS RX300   (RM785E)

CIRCUIT INSPECTION

DTC

B1211 / 11

Driver door ECU communication stop

CIRCUIT DESCRIPTION

This DTC is output when communication stops between driver door ECU and body ECU.

DTC No.

DTC Detecting Condition

Trouble Area

B1211/11

No communication from driver door ECU more than 10 se-

S Driver door ECU

B1211/11

No communication from driver door ECU more than 10 se

conds.

Driver door ECU

S Wireharness

WIRING DIAGRAM

I19269

RHD Vehicle:

R14

5

MPX1

MPX2

R14

4

Rear Left
Door ECU

BA1

11

V

V

IA2

11

Y–R

Y–R

IC1

5

Front Passenger
Door ECU

MPX2

MPX1

11

F17

10

F17

Y

IC1

10

Y

E9

11

E9

18

Engine and 
ECT ECU

MPX2

MPX1

W–R

W–R

W–R

ID1

7

M6

2

Sliding Roof
Control ECU

MPX1

W–R

Body ECU

MPX1

MPX2

11

B5

20

B8

B–O

I17

5

I17

12

Instrument Control
Panel

MPX+

MPX–

(*1)

(*1)

I16

13

I16

12

(*2)

(*2)

Y–B

C12

21

C12

17

Combination
Meter ECU

MPX+

MPX–

B

IE1

4

*1: Europe 
*2: Except Europe

T5

8

T5

7

MPX1

MPX2

Theft Deterrent ECU

B

Y–R

5

IL1

Y–R

D12

11

Driver Door
ECU

MPX2

MPX1

D12

10

Y

10 IL1

V

3

IM1

Y–R

BB1

10

Y–R

R16

4

R16

5

Rear Right
Door ECU

MPX2

MPX1

W

11

BB1

Y

D11

9

D11

10

Double Lock Door

Control Relay

MPX1

MPX2

W

BD1

4

W

BA1

10

W

–

DIAGNOSTICS

MULTIPLEX COMMUNICATION SYSTEM

DI–689

LEXUS RX300   (RM785E)