Page 635 of 4087
20CD playerMAGAZINE CANNOT BE INSERTED INTO AUTO
CHANGER
Is radio operating normally?
Is there battery voltage between the following termi-
nals with connector connected?
Radio receiver assembly C5 ± ground
Is there continuity between the following terminals
with connector disconnected?
CD auto changer A4 ± Radio receiver assembly C5
Is there continuity between the following terminals
with connector disconnected?
CD auto changer A9 ± ground
CD auto changer faulty. Wire harness faulty.
Radio receiver assembly faulty.
Go to No. 1.
Is there continuity between the following terminals
with connector disconnected?
CD autochanger A9 ± Radio receiver assembly C4
Wire harness faulty. Radio receiver as-
sembly faulty.
±
BODY ELECTRICAL SYSTEM AUDIO SYSTEMBE±249
WhereEverybodyKnowsYourName
Page 636 of 4087
21CD playerMAGAZINE IS INSERTED, BUT DISPLAY DOES
NOT INDICATE ºCDº
Is radio operating normally?
Is there battery voltage between the following
terminals with connector connected?
Radio receiver assembly C12 ± ground
Wire harness faulty.Radio receiver assembly faulty.
Go to No. 1.
Is there battery voltage between the following
terminals with connector connected?
Radio receiver assembly C12 ± CD auto
changer A3
Is there battery voltage between the following
terminals with connector connected?
Radio receiver assembly C3 ± CD auto changer
B1
Radio receiver assembly C8 ± CD auto changer
B3
Radio receiver assembly C9 ± CD auto changer
B2
Radio receiver assembly C10 ± CD auto changer
B10
Is there battery voltage between the following
terminals with connector disconnected?
Radio receiver assembly C3 ± ground
Radio receiver assembly C8 ± ground
Radio receiver assembly C9 ± ground
Radio receiver assembly C10 ± ground
Temporarily install another CD auto changer.
Functions OK? CD auto changer faulty. Wire harness faulty.
Wire harness faulty.
Radio receiver assembly faulty
BE±250±
BODY ELECTRICAL SYSTEM AUDIO SYSTEM
WhereEverybodyKnowsYourName
Page 637 of 4087
22CD playerDISPLAY INDICATES, BUT NO SOUND IS
PRODUCED (EXCEPT WOOFER)
Is radio operating normally?Wire harness faulty.
Is there battery voltage between the following ter-
minals with connector connected?
Power amplifier A14 ± ground
Power amplifier A10 ± ground
Wire harness faulty.
Is there battery voltage between the following ter-
minals with connector connected?
Power amplifier A6 ± ground
Is there battery voltage between the following ter-
minals with connector connected?
Power amplifier A7 ± ground Is there battery voltage between the following ter-
minals with connector disconnected?
Radio receiver assembly B6 ± Power switch 13.
Is there battery voltage between the following ter-
minals with connector disconnected?
Radio receiver assembly B1±Power switch 14
Radio receiver assembly B3±Power switch 11
Wire harness faulty.
Power switch faulty.
Wire harness faulty.
Radio receiver assem-
bly faulty. Wire harness faulty.
Power switch faulty.
Is resistance value about 50 k between terminals
B3±B6 of radio receiver assembly?
Temporarily install another CD auto changer.
Functions OK? CD auto changer faulty.Is there continuity between the following terminals
with connector disconnected?
Radio receiver assembly A1±Power amplifier A6.
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.
Radio receiver assembly faulty.
±
BODY ELECTRICAL SYSTEM AUDIO SYSTEMBE±251
WhereEverybodyKnowsYourName
Page 638 of 4087
23CD playerANY SPEAKER DOES NOT WORK
(EXCEPT WOOFER).
Is there continuity between the following terminals
with connector disconnected?
Fr: Power amplifier B1±FR speaker 1
Power amplifier B5±FR speaker 2
FL: Power amplifier B2±FL speaker 1
Power amplifier B6±FL speaker 2
RR: Power amplifier B3±RR speaker 1
Power amplifier B4±RR speaker 2
RL: Power amplifier B8±RL speaker 1
Power amplifier B9±RL speaker 2
Is there continuity between the following terminals
with connector disconnected?
FR: Power amplifier B1±ground
Power amplifier B5±ground
FL: Power amplifier B2±ground
Power amplifier B6±ground
RR: Power amplifier B3±ground
Power amplifier B4±ground
RL: Power amplifier B8±ground
Power amplifier B9±ground Wire harness faulty
(The wire harness for the FR speaker passes
through the transceiver, so the transceiver side
should be checked) Wire harness faulty
(The wire harness for the FR speaker passes
through the transceiver, so the transceiver side
should be checked)
Speaker faulty. Radio receiver assembly faulty.
Is radio operating normally?
Temporarily install another speaker.
Functions OK? Wire harness faulty.
Wire harness faulty.
Is there continuity between the following terminals
with connector disconnected?
FR: Radio receiver assembly A7±Power amplifier
A1
FL: Radio receiver assembly A6±Power amplifier
A2
RR: Radio receiver assembly A15±Power amplifi-
er A7
RL: Radio receiver assembly A14±Power amplifi-
er A8
Is there continuity between the following terminals
with connector disconnected?
FR: Radio receiver assembly A7±ground
FL: Radio receiver assembly A6±ground
RR: Radio receiver assembly A15±ground
RL: Radio receiver assembly A14±ground
BE±252±
BODY ELECTRICAL SYSTEM AUDIO SYSTEM
WhereEverybodyKnowsYourName
Page 639 of 4087
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
Page 640 of 4087
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
Page 641 of 4087
![LEXUS SC400 1991 Service Repair Manual
26CD playerWOOFER DOES NOT WORK
HINT: The part names and terminals indicated in brackets ( ) are for models\
with a Nakamichi system.
Is radio operating normally?
Is there battery voltage between th](/manual-img/36/57051/w960_57051-640.png "LEXUS SC400 1991 Service Repair Manual
26CD playerWOOFER DOES NOT WORK
HINT: The part names and terminals indicated in brackets ( ) are for models\
with a Nakamichi system.
Is radio operating normally?
Is there battery voltage between th")
26CD playerWOOFER DOES NOT WORK
HINT: The part names and terminals indicated in brackets ( ) are for models\
with a Nakamichi system.
Is radio operating normally?
Is there battery voltage between the following ter-
minals with connector connected?
Woofer amplifier 3 (Power amplifier C3) ± ground
Woofer amplifier 4 (Power amplifier C4) ± ground
Woofer faultyRadio receiver assembly faulty.
Wire harness faulty.
Wire harness faulty.
Wire harness faulty.
Wire harness faulty.
Wire harness faulty.
Is there battery voltage between the following ter-
minals with connector connected?
Woofer amplifier 6 (Power amplifier C6) ± ground
Is there continuity between the following terminals
with connector disconnected?
Woofer amplifier 7 (Power amplifier C7) ± ground
Is there continuity between the following terminals
with connector disconnected?
Woofer amplifier 9 (Power amplifier C9) ±
Woofer speaker 2
Woofer amplifier 10 (Power amplifier C10) ±
Woofer speaker 1
Is there continuity between the following terminals
with connector disconnected?
Woofer amplifier 9 (Power amplifier C9) ± ground
Woofer amplifier10 (Power amplifier C10) ± ground
Temporarily install another woofer.
Functions OK?
Radio receiver assembly faulty.
±
BODY ELECTRICAL SYSTEM AUDIO SYSTEMBE±255
WhereEverybodyKnowsYourName
Page 642 of 4087
27CD playerWOOFER VOLUME FAINT
HINT: The part names and terminals indicated in brackets ( ) are for models\
with a Nakamichi system.
Is radio operating normally?
Is there continuity between the following terminals
with connector disconnected?
Radio receiver assembly D1 ± Woofer amplifier 1
(Power amplifier 1 (Power amplifier C1)
Radio receiver assembly D5 ± Woofer amplifier 1
(Power amplifier 5 (Power amplifier C5) Radio receiver assembly faulty.
Wire harness faulty.
Wire harness faulty. Woofer amplifier faulty.
Radio receiver assembly faulty. Temporarily install another woofer amplifier.
Functions OK? Is there continuity between the following terminals
with connector disconnected?
Radio receiver assembly D1 ± ground
Radio receiver assembly D5 ± ground
BE±256±
BODY ELECTRICAL SYSTEM AUDIO SYSTEM
WhereEverybodyKnowsYourName
![LEXUS SC400 1991 Service Repair Manual
27CD playerWOOFER VOLUME FAINT
HINT: The part names and terminals indicated in brackets ( ) are for models\
with a Nakamichi system.
Is radio operating normally?
Is there continuity between the foll](/manual-img/36/57051/w960_57051-641.png "LEXUS SC400 1991 Service Repair Manual
27CD playerWOOFER VOLUME FAINT
HINT: The part names and terminals indicated in brackets ( ) are for models\
with a Nakamichi system.
Is radio operating normally?
Is there continuity between the foll")