Lexus RX300 (MCU15). Manual — part 335

DI1OI–22

I19257

Short Pin

Body ECU

BSUB

ACC

IG

WIG

BECU

GND1

GND2

W–B

B8

F11
FL Block

P FR
DOOR

B5

B8

B8

W–B

5

8

4

1

5

9

2

6

2I

2A

3A

3F

GAUGE

1K

AM1

1H

1G1

1J

6

11

18

G–B

L–B (*1)

R–L

W

B–Y

R–B

L–Y

Battery

ALT

J/B No. 3

ECU–B

Engine Room J/B

1

C

4

FL DOOR

ACC

6

1G

10

W–R

4

IJ1

20

W

1

1A

RR WIP

W

2

10

6

Instrument Panel J/B

Instrument Panel J/B

1C

10

B5

B5

B8

2

J/B No. 3

3F

3H

9

J5
J/C

A

IE

IH

W–B

W

L–B
(*2)

W–L

(*1)

(*2)

Instrument Panel J/B

L–B
(*2)

C

J20 J/C

L–B
(*2)

2A

2

L–B (*1)

1

2

7

1J

*1: LHD
*2: RHD

RADIO No. 2

1E

6

1C

2

1C

7

3

AM1

W–L

GR

P

I15
Ignition
SW

DI–572

–

DIAGNOSTICS

BODY CONTROL SYSTEM

LEXUS RX300 (RM785E)

CIRCUIT INSPECTION

Power source circuit

CIRCUIT DESCRIPTION

This circuit provides power to operate the Body ECU.

WIRING DIAGRAM

–

DIAGNOSTICS

BODY CONTROL SYSTEM

DI–573

LEXUS RX300 (RM785E)

INSPECTION PROCEDURE

1

Check RR WIPER, RADIO No.2, DOOR and GAUGE fuse.

CHECK:
Check continuity of RR WIPER, RADIO No. 2, DOOR and GAUGE fuse.
OK:
Continuity

NG

Replace the failure fuse.

OK

2

Check voltage between terminals WIG, ACC, BSUB, BECU and IG and GND1 or
GND2 of Body ECU connector.

PREPARATION:
Turn ignition switch ON.
CHECK:
Measure voltage between terminals WIG, ACC, IG, and GND1, GND2.
OK:

Voltage: 10 – 14V

PREPARATION:
(a)

Turn ignition switch OFF.

(b)

Disconnect the Body ECU connector.

CHECK:
Measure voltage between terminals BSUB, BECU and GND1, GND2.
OK:

Voltage: 10 – 14V

OK

Proceed to next circuit inspection shown on
problem symptoms table (See page DI–570).

NG

DI–574

–

DIAGNOSTICS

BODY CONTROL SYSTEM

LEXUS RX300 (RM785E)

3

Check wireharness and connector between Body ECU and body ground.

NG

Repair or replace wireharness or connector.

OK

Check and repair wireharness and connector
between Body ECU and battery.

I19258

G–R

16

15

4

TAIL

HEAD

A

R–L

P

J9
J/C

Combination Switch

14 13

12

IG

OFF

TAIL

HEAD

AUTO

Body ECU

B6

B5

B5

*

A

16

*: LIGHT CONTROL SW

T

H

A

EL

W–B

–

DIAGNOSTICS

BODY CONTROL SYSTEM

DI–575

LEXUS RX300 (RM785E)

Light control switch circuit

WIRING DIAGRAM

DI1OL–14