audio LEXUS SC400 1991 Service Manual PDF

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
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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±
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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
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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±
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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
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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±
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31NoiseNOISE PRODUCED WHEN ENGINE STARTS
Whistling noise which becomes high±pitched when
accelerator strongly depressed, disappears shortly
after engine stops.Whining noise occurs when A/C is operating.
Scratching noise occurs during sudden accel-
eration, driving on rough roads or when ignition
switch is turned on.
Clicking sound heard when horn button is
pressed, then released. Whirring/grating sound
when pushed continuously.
Murmuring sound, stops when engine stops. Tick±tock noise, occurs in coordination with
blinking of flasher.
Noise occurs during window washer operation.Scratching noise occurs while engine is running,
continues a while even after engine stops.Scraping noise in time with wiper beat.
Other type of noise. Alternator noise.
A/C noise.
Fuel gauge noise.
Horn noise.
Ignition noise. Turn signal flasher noise.
Washer noise. Water temp. gauge noise.
Wiper noise.
±
BODY ELECTRICAL SYSTEM AUDIO SYSTEMBE±259
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32AntennaANTENNA±RELATED
Does antenna extend when radio switched ON?Wire harness faulty.
Is there battery voltage between the following
terminals with connector disconnected?


Motor antenna control relay 6 ± ground

Motor antenna control relay 14 ± ground

Motor antenna control relay 3 ± ground
Wire harness faulty.Replace fuses.
Radio receiver assembly faulty.
Check if ECU±IG, RADIO No. 1 and RADIO No.
2 fuse are OK.
ªAMº button turned ON.
Is there battery voltage between the following
terminals with connector connected?

Radio receiver assembly A9 (*A1) ± ground

Radio receiver assembly A8 ± ground

Radio receiver assembly D4 ± ground

Radio receiver assembly D10 ± ground Radio receiver side
faulty.
Motor antenna faulty.
Temporarily install another motor antenna is
radio operating normally?
Glass printed antenna faulty.
Check if glass printed antenna is OK.
Is there continuity between the following terminals
with connector disconnected?

Motor antenna control relay 4 ± ground
Continued on next page.
BE±260±
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Wire harness faulty.
Is there continuity between the following terminals
with connector disconnected?

Radio receiver assembly A9 (*A1) ± Motor anten-
na control relay 4

Radio receiver assembly A8 ± Motor antenna
control relay 5

Radio receiver assembly D4 ± Motor antenna
control relay 2

Radio receiver assembly D10 ± Motor antenna
control relay 12
Temporarily install another motor antenna con-
trol relay. Functions OK? Motor antenna control relay faulty.
Motor antenna control relay faulty.
±
BODY ELECTRICAL SYSTEM AUDIO SYSTEMBE±261
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PRECAUTIONS
Take care to observe the following precautions when performing inspection\
s or removal and replacement
of body electrical related parts.
1. SRS AIR±BAG SYSTEM

Work must be started approx. 20 seconds after the ignition is set to the Loc\
k position and the negative
(±) terminal cable is disconnected from the battery. (See page AB±2)

When disconnecting any of the connectors in the SRS AIR±BAG system, be su\
re to Lock the ignition
switch and disconnect the battery negative (±) terminal first. Since the connectors are twin \
lock type
connectors, disconnect the connectors only after releasing the first stage lock.

When connecting SRS AIR±BAG system connectors, be sure to lock them secur\
ely. (If the connectors
are not locked securely, the system may not operate when needed.)

Always store the steering wheel pad with the pad surface facing upward. (Stor\
ing the pad with its
metallic surface up may lead to a serious accident if the air bag inflates for s\
ome reason.)

When installing the spiral cable, be sure the vehicle is in the straight ahe\
ad condition and confirm that
the spiral cable is in the neutral position when it is installed. (See pag\
e BE±40)

INFORMATION LABELS (NOTICE) are attached to the periphery of the air bag componen\
ts. Follow
the NOTICE.
2. MICRO COMPUTER PRESET DRIVING POSITION SYSTEM
Power Seat Control System
Power Mirror Control System
Power Tilt and Telescopic Steering System

If the battery negative (±) terminal is disconnected, the preset driv\
ing positions stored in memory are
erased, so be sure to note the positions and reset them after the battery termi\
nal is reconnected.
3. AUDIO SYSTEM

If the battery negative (±) terminal is disconnected, the preset AM, F\
M 1 and FM 2 stations stored in
memory are erased, so be sure to note the stations and reset them after the battery terminal is
reconnected.

If the battery negative (±) terminal is disconnected, the ºANTI±\
THEFT SYSTEMº will operate when
the terminal is reconnected, but the radio, tape player and CD player will \
not operate. Be sure to input
the correct ID number so that the radio, tape player and CD player can be o\
perated again.
±
BODY ELECTRICAL SYSTEM PrecautionsBE±7
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