1991 LEXUS SC400 audio

ANTENNA CORD
ANTENNA CORD REMOVAL AND
INSTALLATION
1. REMOVE ANTENNA CORD
(a) Remove the following parts:wInstrument panel assembly
w Right front pillar garnish
w Roof headlining
w Roof side inner garnish
w Right center pillar garnish
w Right rear pillar garnish
w Package tray trim
w Room partition trim
w Luggage compartment RH cover
w Luggage compartment trim front cover
HINT: (See BO±section.)
(b) Remove antenna cord from motor antenna and glass printed antenna.
(c) Disconnect the connectors shown in the figure.
(d) Remove the clips and antenna cord assembly.
2. INSTALL ANTENNA CORD For installation follow the removal procedure in reverse.
±
BODY ELECTRICAL SYSTEM AUDIO SYSTEMBE±217
WhereEverybodyKnowsYourName

TROUBLESHOOTING
NOTICE: When replacing the internal mechanism (ECU part) of the audio system,\
be careful that no part
of your body or clothing comes in contact with the terminals of the lead\
s from the IC, etc. of the replace-
ment part (spare part).
HINT:
This inspection procedure is simple troubleshooting which should be carried \
out on the vehicle during
system operation and is based on the assumption that the cause of trouble lies\
with the system
components (excluding the wires and connectors, etc.).
Always inspect the trouble taking the following items into consideration\
.
Open or short circuit of the wire harness

Connector or terminal connection fault

The cassette tape or compact disc itself may be causing the trouble, so whe\
n troubleshooting the tape
player or CD player, always use a different cassette tape or compact disc first of all to check operation
of the tape player or CD player.

For some of problems in the following problem chart, the AUDIO SYSTEM CHECKER can be used
to inspect malfunctions of the Radio or Tape Player, and the CD PLAYER CHECKER can be used to
inspect the CD player.
The portions indicated by on the flow charts on the following pages can be\
inspected using a CHECK-
ER.
For instructions on how to connect the checker to the vehicle and how to\
use the checker, please refer
to the instruction Manual for AUDIO SYSTEM CHECKER or CD PLAYER CHECKER.
BE±218
±
BODY ELECTRICAL SYSTEM AUDIO SYSTEM
WhereEverybodyKnowsYourName

 
\
 \

Problem No.
 \
 \
Radio not operating when power switch turned to ºONº 1
 


\
 
\

\

Display indicates when power switch turned to ºONº, but no sound (\
including ºnoiseº)
is produced (except woofer). 


2
 \
 \
Noise present, but AM±FM not operating 3
 
Radio
\
 \
Any speaker does not work (except woofer). 4
 Radio\
 \
Volume faint (except woofer). 5 \
 \
Woofer does not work. 6 


\
 
\

\
Woofer volume faint. 

7
 \
 \
Reception poor. 8
 \
 \
Preset memory disappears. 9
 \
 \
Volume remains at maximum level. 10
 \
 \
Cassette tape cannot be inserted. 11
 \
 \
Cassette tape will not eject. 12
 \
 \
Display indicates, but no sound is produced (except woofer). 13 \
 \
Any speaker does not work (except woofer). 14 

Tape player
\
 
\

\
Volume faint (except woofer). 

15
 \
 \
Woofer does not work. 16
 \
 \
Woofer volume faint. 17
 \
 \
Sound quality poor. 18
 \
 \
Volume remains at maximum level. 19
 \
 \
Magazine cannot be inserted into auto changer. 20
 \
 \
Magazine is inserted, but display does not indicate ºCDº. 21 \
 \
Display indicates, but no sound is produced (except woofer). 22 


\
 
\

\
Any speaker does not work (except woofer). 

23
 CDplayer\
 \
Volume faint (except woofer). 24
 CD player\
 \
RH channel or LH channel speaker volume faint. 25
 \
 \
Woofer does not work. 26
 \
 \
Woofer volume faint. 27
 \
 \
Sound quality poor. 28
 \
 \
Volume remains at maximum level. 29 
Noise
\
 \
Noise produced by vibration or shock while driving. 30 


Noise\
 
\

\
Noise produced when engine starts. 

31
 Antenna\
 \
Antenna±related. 32
±
BODY ELECTRICAL SYSTEM AUDIO SYSTEMBE±219
WhereEverybodyKnowsYourName

1RadioRADIO NOT OPERATING WHEN POWER
SWITCH TURNED TO ºONº.
A. Without CD player type
Does radio operate normally when AM or FM
button is pushed?
Check if RADIO NO.1 and RADIO NO.2 fuses
are OK.Is there battery voltage between the following
terminals with connector connected?

Radio receiver assembly A3±ground

Radio receiver assembly A4±ground
Is there continuity between the following termi-
nals with connector disconnected?

Radio receiver assembly A11±ground Radio receiver assembly faulty.Wire harness faulty
Wire Harness faulty.
Replace fuse.
Inspect power switch. Wire harness faulty.
Is there continuity between the following terminals
with connector disconnected?


Radio receiver assembly B2±power switch 12

Radio receiver assembly B4±power switch 11
Wire Harness faulty.
Is there battery voltage between the following
terminals with connector connected?


Radio receiver assembly A11±Power
amplifier A11
Is there continuity between the following termi-
nals with connector disconnected?

Power amplifier B7±ground
Power amplifier faulty.
BE±220±
BODY ELECTRICAL SYSTEM AUDIO SYSTEM
WhereEverybodyKnowsYourName

B. with CD player type
Does radio operate normally when AM or FM
button is pushed?
Is there battery positive voltage between the
following terminals with connector connected?

Radio receiver assembly A3±ground

Radio receiver assembly A4±ground
Check if RADIO No.1 and RADIO No.2 fuses are OK.
Is therecontinuity between the following termi-
nals with connector disconnected?

Radio receiver assembly A11±ground Replace fuse.
Wire harness faulty
Radio receiver assembly faulty.
Wire harness faulty.
Wire harness faulty. Inspect power switch.
Wire harness faulty
Is there continuity voltage between the following
terminals with connector connected?


Radio receiver assembly B2±Power switch 12

Radio receiver assembly B3±Power switch 11
Is there continuity between the following terminals
with connector disconnected?

Radio receiver assembly A11±power amplifier A11
Is there continuity between the following terminals
with connector disconnected?

Radio receiver assembly B7±ground
Power amplifier faulty.
±
BODY ELECTRICAL SYSTEM AUDIO SYSTEMBE±221
WhereEverybodyKnowsYourName

2Radio
DISPLAY INDICATES WHEN POWER SWITCH
TURNED TO ºONº, BUT NO SOUND (INCLUDING
ºNOISEº) IS PRODUCED (EXCEPT WOOFER)
A. without CD player type
Is there continuity between the following terminals
with connector disconnected?

Radio receiver assembly B1±Power switch 14

Radio receiver assembly B3±Power switch 11
Radio receiver assembly faulty.
Is tape player operating normally?
When the volume switch is turned from minimum
to maximum, does resistance between terminals
B1 ± B3 of radio receiver assembly change from
0 to 50 k .
Power switch faulty. Wire harness faulty.
Is resistance value approx. 50  between termi-
nals is B3±B6 of radio receiver assembly?
Radio receiver assembly faulty. Is there continuity between the following terminals
with connector disconnected?


Radio receiver assembly B6±Power switch 13
Power switch faulty. Wire harness faulty.
BE±222±
BODY ELECTRICAL SYSTEM AUDIO SYSTEM
WhereEverybodyKnowsYourName

B. with CD player type
Is there continuity between the following terminals
with connector disconnected?

Radio receiver assembly B1±Power switch 14

Radio receiver assembly B3±Power switch 11
Is tape player operating normally?
Power switch faulty.Wire harness faulty.
Is resistance value about 50 k
 between termi-
nals is B3±B6 of radio receiver assembly?
Wire harness faulty.
Is there continuity between the following terminals
with connector disconnected?

Radio receiver assembly A1±Power amplifier A6
Is there continuity between the following terminals
with connector disconnected?


Radio receiver assembly B6±Power switch 13
Power switch faulty.
Wire harness faulty.
Is there battery positive voltage between the follow-
ing terminals with connector connected?

Power amplifier A14±ground

Power amplifier B10±ground
Is there battery positive voltage between the follow-
ing terminals with connector connected?

Power amplifier A6±ground Radio receiver assembly faulty.
When the volume switch is turned from mini-
mum to maximum, does resistance between
terminals B1±B3 of radio receiver assembly
change from 0 to 50 k ?
Wire harness faulty.
Power amplifier faulty. Is there continuity between the following terminals
with connector disconnected?


Power amplifier B7±ground Radio receiver assem-
bly faulty.
Wire harness faulty.
±
BODY ELECTRICAL SYSTEM AUDIO SYSTEMBE±223
WhereEverybodyKnowsYourName

3RadioNOISE PRESENT, BUT AM±FM NOT OPERATING
Go to No. 32Radio receiver assembly faulty.
BE±224±
BODY ELECTRICAL SYSTEM AUDIO SYSTEM
WhereEverybodyKnowsYourName