CD changer LEXUS SC400 1991 Service User Guide

Temporarily install another power amplifier.
Function is OK?Radio receiver assembly faulty. Power amplifier faulty.
24CD playerVOLUME FAINT (EXCEPT WOOFER)
Is radio operating normally?
When the volume switch is turned from minimum to
maximum, does resistance between terminals
B1±B3 of radio receiver assembly changer from 0
to 50 k 
Radio receiver assembly faulty.
Power switch faulty.
Wire harness faulty.
Power amplifier faulty.
Radio receiver assembly faulty.
*Is there battery voltage between the following
terminals with connector disconnected?


Radio receiver assembly D3 ± ground
Temporarily install another power amplifier.
Function is OK?
±
BODY ELECTRICAL SYSTEM AUDIO SYSTEMBE±253
WhereEverybodyKnowsYourName

25CD playerRH CHANNEL OR LH CHANNEL SPEAKER
VOLUME FAINT
Is there continuity between the following terminals
with connector disconnected?

RH: :Radio receiver assembly C1 ±
CD auto changer A1
:Radio receiver assembly C6 ±
CD auto changer A5

LH: Radio receiver assembly C2 ±
CD auto changer A2
:Radio receiver assembly C7 ±
CD auto changer A6 Radio receiver as-
sembly faulty.
Is radio operating normally?
Wire harness faulty.
Wire harness faulty.
Is there continuity between the following terminals
with connector disconnected?

RH: :Radio receiver assembly C1 ± ground
:Radio receiver assembly C6 ± ground

LH: :Radio receiver assembly C2 ± ground
:Radio receiver assembly C7 ± ground
Temporarily install another CD auto changer.
Functions OK? CD auto changer faulty.
Radio receiver assembly faulty. Power amplifier
faulty.
Temporarily install another power amplifier.
Functions OK.
BE±254±
BODY ELECTRICAL SYSTEM AUDIO SYSTEM
WhereEverybodyKnowsYourName

28CD playerSOUND QUALITY POOR
Is radio operating normally?
Is speaker properly installed? Temporarily install another speaker
Functions OK? Temporarily install another CD auto changer.
Functions OK?
Temporarily install another power amplifier.
Functions OK? Radio receiver assembly faulty. Speaker faulty. Speaker installation faulty
Power amplifier faulty. Radio receiver assem-
bly faulty CD changer faulty.
29CD playerVOLUME REMAINS AT MAXIMUM LEVEL
Is radio operating normally?
Radio receiver assembly faulty.
Wire harness faulty.
Is there continuity between the following terminals
with connector disconnected?

Radio receiver assembly B1 ± Power switch 14

Radio receiver assembly B3 ± Power switch 11
Power switch faulty.
Radio receiver assembly faulty.
When the volume switch is turned from minimum to
maximum, does resistance between terminal 11±14
of power switch changes from 0 to 50 k
?
±
BODY ELECTRICAL SYSTEM AUDIO SYSTEMBE±257
WhereEverybodyKnowsYourName

30NoiseNOISE PRODUCED BY VIBRATION OR SHOCK
WHILE DRIVING
Is radio properly installed?
Is radio receiver assembly properly installed?
*1 Is radio power amplifier properly installed?
*2 Is woofer amplifier properly installed?*1 Is CD auto changer properly installed?
With vehicle stopped, lightly tap each part.
Is noise produced? Speaker installation faulty.
Radio receiver assembly installation faulty.
Power amplifier installation faulty.
Woofer amplifier installation faulty.
CD auto changer installation faulty. Each part faulty.
Noise produced by static electricity is accululating in the vehicle body\
.
BE±258±
BODY ELECTRICAL SYSTEM AUDIO SYSTEM
WhereEverybodyKnowsYourName

Fuel Pump ECUAuto Antenna Motor and Relay
Power Seat ECU
(For Passenger's Seat)
Power Seat ECU
(For Driver's Seat) CD Automatic Changer
Wireless Door Lock ECU
Moon Roof Control Relay
Locations of ECUs (Cont'd)
Many ECUs are mounted in this vehicle.
Take the following precautions during body repair to prevent damage to th\
e ECUs.


Before starting electric welding operations, disconnect the negative (-\
) terminal cable from the battery.
When the negative (-) terminal cable is disconnected from the battery, memory of the clock and audio
systems will be cancelled. So before starting work, make a record of the\
contents memorized by each
memory system. Then when work is finished, reset the clock and audio sys\
tems as before.
When the vehicle has tilt and telescopic steering, power seat and outsid\
e rear view mirror, which are all
equipped with memory function, it is not possible to make a record of th\
e memory contents.
So when the operation is finished, it will be necessary to explain this \
fact to the customer, and request
the customer to adjust the features and reset the memory.

Do not expose the ECUs to ambient temperatures above 80 °C (176 °F).
NOTICE: If it is possible the ambient temperature may reach 80°C (176°F) or, more, remove the ECUs
from the vehicle before starting work.

Be careful not to drop the ECUs and not to apply physical shocks to them\
.
5. COMPONENTS ADJACENT TO THE BODY PANELS
Various types of component parts are mounted directly on or adjacently to\
the body panels.
Strictly observe the following precautions to prevent damaging these com\
ponents and the body panels
during handling.

Before repairing the body panels, remove their adjacent components or ap\
ply protective covers over
the components.

Before prying components off using a screwdriver or a scraper, etc., attach protective tape to the tool
tip or blade to prevent damaging the components and the body paint.

Before removing components from the outer surface of the body, attach protective tape to the body to
ensure no damage to painted areas.
HINT: Apply touch-up paint to any damaged paint surfaces.

Before drilling or cutting sections, make sure that there are no wires, \
hoses, etc., on the reverse side.
INTRODUCTIONIN-9
WhereEverybodyKnowsYourName

(b) Remove the six nuts and five bolts holding the intake airconnector to the air intake chamber.
(c) Disconnect the check connector and harness protector from the air intake chamber.
(d) Remove the five bolts, two nuts, intake air chamber and two gaskets.
INSPECTION OF ACOUSTIC CONTROL
INDUCTION SYSTEM (ACIS)
1. INSPECT IACV (a) With 53.3 kPa (400 mmHg, 15.75 in.Hg) of vacuumapplied to the actuator, check that the actuator rod
moves.
(b) One minute after applying the vacuum in (a), check that the actuator rod does not return.
If the operation is not as specified, turn the adjusting screw.
2. INSPECT VACUUM TANK (a) Check that air flows from port A to port B.
(b) Check that air does not flow port B to port A.
(c) Plug port B with your finger, and apply 53.3 kPa (400
mmHg, 15.75 in.Hg) of vacuum to port A, and check that
there is no changer in vacuum after one minute.
If the operation is not as specified, replace the vacuum tank.
±
EFI SYSTEMFI±59Air Induction System (Acoustic Control Induction System (ACIS)
WhereEverybodyKnowsYourName

30
ELECTRICAL WIRING ROUTING
Position of Parts in Body
A 30 ABS Speed Sensor Rear LH D 10 Door Lock Motor, Door Unlock Detection SW and
A 31 ABS Speed Sensor Rear RH Door Open Detection SW LH
A 32 Auto Antenna Motor and Relay D 11 Door Lock Motor, Door Unlock Detection SW andDoor Open Detection SW RH
C 20 CD Automatic Changer D 12 Driving Position Memory and Return SW
C 21 CD Automatic Changer
C 22 Choke Coil F 11 Front Door Speaker LH F 12 Front Door Speaker RH
D 4 DAY/NIGHT Shift SW F 14 Fuel Lid Opener Solenoid
D 5 Door Courtesy Light LH F 15 Fuel Pump
D 6 Door Courtesy Light RH F 16 Fuel Pump ECU
D 7 Door Key Lock and Unlock SW LH F 17 Fuel Sender
D 8 Door Key Lock and Unlock SW RH F 18 Fuel Sender
D 9 Door Lock Control SW RH H 8 High Mount Stop Light (w/o Rear Spoiler)
H 9 High Mount Stop Light (w/ Rear Spoiler)
L 2 Licence Plate Light
L 3 Light Failure Sensor
L 4 Luggage Compartment Door Opener Motor
L 5 Luggage Compartment Key Unlock SW
L 6 Luggage Compartment Light SW
L 7 Luggage Compartment Light
WhereEverybodyKnowsYourName

OVERALL ELECTRICAL WIRING DIAGRAM
1234
20 LEXUS SC300 (
Cont . ne xt pa ge )
4 ACC
IG1
ST1
AM1 3
2
1J
7
1B
4
5
BV3 4
BV3 15
BV3 14
BV3 13
BV3 12
BV3 1
BV3 8
BV3 11
BV3 10
BV3 3
BV3 2
BV3 16
BV3 10
BV1 11
IQ2 2
IE1
3
IG2 2
2
74 3F 8F 9F 10F 1F 6F 11F 2F 7F 4F 5F 12F 3E 2C 6C 1C 3C 4D
6 1G 3G 2G 6G 1H 5H 8H 2H 6H 9H 4H 3H
3
IQ1 7
BV2
2
BV1 1
BV1 19
BV1 7
BV1 18
BV1
1J
8
1E
10
7D 6D 15D 14D 5D 13D 12D 11D 1E 5E 1D 2E 8D 4E 10E
3D
13
BV1
12
BV1
16
BV1
15
BV1
11
BV1
14
BV1
8
BV1
17
BV1
6
BV1
5
BV1
4
BV1
9
BV1
3
BV1
7H
B± Y
GR
L±Y
L±W B±RL±G
Y±R
R±B L±B
P± L W
BR B
G Y
W
BR L
R
L±YW
P±L
B± Y
W
W± L
W
G±WG± OY±R Y± L
B
W
BR
L
R
Y±B
V±W G±B
V
L±Y L±Y W
P±L
L±Y
L±Y
GR
L±Y
L±Y
P± G
L±W
Y±R GR
GR
L±Y
L±W B± R
L±G
Y± R
G±Y
R±W R± L
G± R V
G± B
V±W Y± B R
L
BR W
B
Y± L
Y±R
G± O
G±W
R L
BR
WY
G
BR±B BR
B
W
P±L
R± B
P±L
W
B
BR G
Y
W
BR
L
R
L±B R± B
GR
To Luggage Compar tment
light SW< 6±3>
From Telephon Tr ans ceiv er
and Speaker Relay< 18±1>
To A/C Control SW and Radio SW
< 22±4>
From A/C Control SW and Radio SW
< 22±4>
40A
IGSW I15
IGNITION SW
R± W
TXM+ TXM± TXS+ TXS± CDR+ CDR± SGND CDL+ CDL± GND +B ACC SW
TXM+ TXM± TXS+ TXS± CDR+ CDR± SGND CDL+ CDL± GND +B
BATTERY
60A MAIN 100A AM1
120A ALTF9
FUSE BLOCK F¥
RF¥ LR¥RR¥ L MUTE B E EP GND S GND RU+ RU± A MP MUTE
ACC TLMT PWR VOL+ VOLC SGN1 B ACC ANT ANTA ANTB
P±L
7 . 5A RA DI O No. 220A RADIO No. 1
CD PL AYER
CD A UTOMAT I C CHA NGE R
RA DI O A ND P LA YE R
Power
SourceRadio and Player
(
w/ CD Player )
(
SHI ELDED )
(
SHIELDED )
( SHIELDED )(
SHI ELDED)
( SHI EL DED )
( SHI EL DED )
(
PIONEER )
( PIONEER )
7 8
(
SHI EL DED )
C9 R2 , R3 , R4
F DCE
12
3456
12 34
5678910
GH
CD AUTOMATIC CHANGER
C2 0 C2 1
C20 , C21 GH
123 45
6789101112 F
CD PLAYER
C9 123 45
6 7 8 9 10 11 12
12
3456D
E
RADIO AND PLAYER
R2
R4 R3 C(
PI ONEER )
3
4
1234 567
8 9 10 11 12 13 14 15
BR BR
BR
BR
WhereEverybodyKnowsYourName

212
RADIO AND PLAYER (w/ CD PLAYER)
BV3
5BV3 4BV315 BV3 11 BV314 BV3 13 BV3 1BV38BV3 12 BV310 BV3 3BV32BV316 Bc1 25
I31 I31
I31
B16 B16
B25
D
3D 8D9D10 D 1D6D 11 D2D7D 4D5D12
A
1A 3A2A 6B1B 5B 8B2B6B 9B4B 3B7
C
2C 6C1C3
1
G±RR±L
R±W
G±Y
R±W G±W
G±O
Y±RY±L
B
W
BR
L
R
Y±B
V±W G±B
R±W
G±W
G±O
Y±RY±L
B
W
BR L
R
Y±B
V±W G±B
12 13 14 11
TXM+ TXM± TXS+ TXS± CDR+ CDR±
TXM+ TXM± TXS+ TXS± CDR+ CDR±
SGND CDL+ CDL±
SGND CDL+ CDL±GND +B ACC SW
GND +B ACC
PWR
VOL+
VOLC
SGND
PWR VOL+ VOLC SGND
A/C CONTROL SW
AND RADIO SW A1 5 LUGGAGE
COMPARTMENT
LIGHT SW
L6
CD AUTOMATIC CHANGER
C20 ,
C21
A
B
R2 , R3 ,
R 4
A B C RADIO AND PLAYER C9
DCD PLAYER
BR BR
BR±W
BR±W
WhereEverybodyKnowsYourName