Lexus RX300 (MCU15). Service manual - part 333

DI1OD–12

Customer Problem Analysis

Vehicle Brought to Workshop

Problem Symptom Confirmation

Symptom Simulation

Symptom does not
occur

Circuit Inspection

Identification of Problem

Repair

Confirmation Test

End

Titles inside

are titles of pages in this

manual, with the page number indicated in
the bottom portion. See the indicated pages
for detailed explanations.

1

2

3

6

5

8

P. IN–22

P. DI–678

P.DI–565

P. DI–572

Symptom
occur

Step 6, 8 : Diagnostic steps permitting the use of the 
                  hand–held tester .

7

Multiplex communication system inspection *

4

Problem Symptoms Table

P. DI–570

*: Confirm that there is no trouble by
basic inspection and DTC check

DI–564

–

DIAGNOSTICS

BODY CONTROL SYSTEM

LEXUS RX300   (RM785E)

BODY CONTROL SYSTEM

HOW TO PROCEED WITH TROUBLESHOOTING

HINT:
This ECU is connected to the multiplex communication system. Therefore, be sure to check that there is no
troubles in the multiplex communication system before performing the trouble shooting.

DI1OE–04

BODY CONTROL SYSTEM Check Sheet

Inspector’s name:

Customer’s Name

Date Vehicle

Registration No.

Registration Year

Frame No.

Odometer Reading

             /               /

km
Mile

Weather Conditions
When Problem
Occurred

Date Problem First Occurred

Frequency Problem Occurs

Weather

                              /                                /

"" Once only

Brought in

"" Key Reminder System

Malfunction
System

Outdoor Temperature

"" Fine    "" Cloudy     ""Rainy     ""Snowy
"" Various/ Others

"" Hot       ""Warm       "" Cool
"" Cold (Approx.     °F (     °C))

"" Constant        "" Sometimes (    times per     day, month)

"" Headlight and Taillight System

"" Illuminated Entry System

"" Light Control System

"" Wiper and Washer System

"" Seat Belt Warning

"" Power Window Control System

"" Power Door Lock Control System

"" Theft Deterrent System

"" Wireless Door Lock Control System

"" Others

–

DIAGNOSTICS

BODY CONTROL SYSTEM

DI–565

LEXUS RX300   (RM785E)

CUSTOMER PROBLEM ANALYSIS CHECK

DI3JL–02

I19136

Brake Fluid Level Warning Switch

Engine Hood Courtesy Switch

Combination Switch
D Light Control Switch
D Headlight Dimmer Switch
D Rear Wiper Switch

Key Unlock Warning Switch

Hazard Warning
Switch

Theft Deterrent
Indicator

Instrument Panel J/B
D RADIO No.2 Fuse
D RR WIP Fuse
D GAUGE Fuse

Parking Brake Switch

Buckle Switch

Wireless Door Lock Receiver

Vanity Light

Personal Light

Vanity Light

Front Interior Light

Rear Interior Light

Rear Wiper Motor

Back Door Lock Motor

Back Door Courtesy Switch

Europe:

Except Europe:

Center Cluster Integration Panel
D Theft Deterrent Indicator

DI–566

–

DIAGNOSTICS

BODY CONTROL SYSTEM

LEXUS RX300   (RM785E)

PARTS LOCATION

DI1OG–16

I07384

B5

B6

B7

B8

Body ECU

–

DIAGNOSTICS

BODY CONTROL SYSTEM

DI–567

LEXUS RX300   (RM785E)

TERMINALS OF ECU

Symbols (Terminals No.)

Wiring Color

Condition

STD Voltage (V)

GND2 ↔ Body Ground 

(B8–2 ↔ Body Ground)

W–B

Constant

Below 1.0

BSUB ↔ GND 1, 2

(B8–4 ↔ B5–9, B8–2)

L–B ↔ W–B

Constant

10 – 14

IG ↔ GND 1, 2

R L ↔ W B

Ignition switch ACC or OFF

Below 1.0

IG ↔ GND 1, 2

(B8–5 ↔ B5–9, B8–2)

R–L ↔ W–B

Ignition switch ON

10 – 14

FFGO ↔ GND1, 2

BR W ↔ W B

Fog light switch OFF

10 – 14

FFGO ↔ GND1, 2

(B8–6 ↔ B5–9, B8–2)

BR–W ↔ W–B

Fog light switch ON

Below 1.0

TRLY ↔ GND1, 2

G W ↔ W B

Ignition switch ON, light control switch OFF

10 – 14

TRLY ↔ GND1, 2

(B8–7 ↔ B5–9, B8–2)

G–W ↔ W–B

Ignition switch ON, light control switch TAIL

Below 1.0

HAZ ↔ GND1, 2

LG B ↔ W B

Hazard warning switch OFF

10 – 14

HAZ ↔ GND1, 2

(B8–11 ↔ B5–9, B8–2)

LG–B ↔ W–B

Hazard warning switch ON

Below 1.0

RFOG ↔ GND1, 2

G B ↔ W B

Rear fog light switch OFF

10 – 14

RFOG ↔ GND1, 2

(B8–13 ↔ B5–9, B8–2)

G–B ↔ W–B

Rear fog ligh switch ON

Below 1.0

SNOW ↔ GND1, 2

Y B ↔ W B

Pattern select switch SNOW

Below 1.0

SNOW ↔ GND1, 2

(B8–15 ↔ B5–9, B8–2)

Y–B ↔ W–B

Pattern select switch except SNOW, Ignition switch ON

10 – 14

IND ↔ GND1, 2

LG ↔ W B

Security indicator light lights up

3 – 6

IND ↔ GND1, 2

(B8–16 ↔ B5–9, B8–2)

LG ↔ W–B

Security indicator light does not light up

Below 1.0

ACC ↔ GND1, 2

GR ↔ W B

Ignition switch OFF

Below 1.0

ACC ↔ GND1, 2

(B8–18 ↔ B5–9, B8–2)

GR ↔ W–B

Ignition switch ACC

10 – 14

BCTY ↔ GND1, 2

W R ↔ W B

Back door courtesy switch OFF (closed)

10 – 14

BCTY ↔ GND1, 2

(B7–5 ↔ B5–9, B8–2)

W–R ↔ W–B

Back door courtesy switch ON (open)

Below 1.0

DBKL ↔ GND1, 2

G W ↔ W B

Driver’s seat belt buckle switch OFF (belt fastened)

10 – 14

DBKL ↔ GND1, 2

(B7–7 ↔ B5–9, B8–2)

G–W ↔ W–B

Driver’s seat belt buckle switch ON (belt unfastened)

Below 1.0

KSW ↔ GND1, 2

L ↔ W B

Ignition key inserted

Below 1.0

KSW ↔ GND1, 2

(B7–8 ↔ B5–9, B8–2)

L ↔ W–B

Ignition key not inserted

10 – 14

HR ↔ GND1, 2

L O ↔ W B

Ignition switch ON and blower motor not operate

10 – 14

HR ↔ GND1, 2

(B7–9 ↔ B5–9, B8–2)

L–O ↔ W–B

Ignition switch ON and blower motor operate

Below 1.0

ILE ↔ GND1, 2

R Y ↔ W B

Each door open

Below 2.0

ILE ↔ GND1, 2

(B7–10 ↔ B5–9, B8–2)

R–Y ↔ W–B

All door closed

10 – 14