radio antenna LEXUS SC300 1991 Service Repair Manual

AUDIO SYSTEM
System Description
RADIO WAVE BAND
The radio wave bands used in radio broadcasting are as follows:
Frequency 30 kHz300 kHz 3 MHz30 MHz300 MHz
DesignationLFMFHFVHF
Radio waveAM
eFM
e
Modulation methodAmplitude modulationFrequency modulation
LF: Low Frequency MF: Medium Frequency HF: High Frequency VH\
F: Very High Frequency
SERVICE AREA
There are great differences in the size of the service area for
AM, FM monaural, and FM stereo broadcasting. Thus it may
happen that FM broadcasts cannot be received even though
AM comes in very clearly.
Not only does FM stereo have the smallest service area, but
it also picks up static and other types of interference (ºnoiseº)
easily.
RECEPTION PROBLEMS
Besides the problem of static, there are also the problems
called ºfadingº, ºmultipathº and ºfade outº. These pro\
blems
are caused not by electrical noise but by the nature of the ra-
dio waves themselves.
Fading
Besides electrical interference, AM broadcasts are also sus-
ceptible to other types of interference, especially at night.
This is because AM radio waves bounce off the ionosphere
at night. These radio waves then interfere with the signals
from the same transmitter that reach the vehicle's antenna di-
rectly. This type of interference is called ºfadingº.
Multipath
One type of interference caused by the bouncing of radio
waves off of obstructions is called ºmultipathº. Multipath oc-
curs when a signal from the broadcast transmitter antenna
bounces off of buildings and mountains and interferes with
the signal that is received directly.
Fade Out
Because FM radio waves are of higher frequencies than AM
radio waves, they bounce off of buildings, mountains, and
other obstructions. For this reason, FM si gnals often seem to
gradually disappear or fade away as the vehicle goes behind
a building or other obstruction. This is called ºfade outº.
BE±196
±
BODY ELECTRICAL SYSTEM Audio System
WhereEverybodyKnowsYourName

MOTOR ANTENNA
MOTOR ANTENNA REMOVAL AND
INSTALLATION
1. REMOVE MOTOR ANTENNA
(a) Remove the antenna nut.
(b) Remove the LH side cover.
(c) Disconnect the motor antenna connector and the antennacord.
(d) Remove the nut and the motor antenna assembly.
2. INSTALL MOTOR ANTENNA
(a) Install the antenna nut.
(b) Connect the motor antenna connector and the antenna cord.
(c) Install the nut.
ANTENNA ROD REMOVAL AND
INSTALLATION
1. REMOVE ANTENNA ROD HINT: Perform this operation with the battery negative (±)
cable connected to the battery terminal.
(a) Turn the ignition switch to ºLOCKº position.
(b) Remove the antenna nut.
(c±1) with CD player
Press the ºAMº and ºCDº buttons on the radio receiver, and
simultaneously turn the ignition switch to ºACCº position.
(c±2) without CD player Press the ºAMº and ºT APEº buttons on the radio receiver, and
simultaneously turn the ignition switch to ºACCº position.
HINT:
w The rod will extend fully and be released from the motor
antenna.
w After removing the antenna rod, leave the ignition switch
at ºACCº.
NOTICE: To prevent body damage when the antenna rod is re-
leased, hold the rod while it comes out.
BE±214±
BODY ELECTRICAL SYSTEM AUDIO SYSTEM
WhereEverybodyKnowsYourName

2. INSTALL ANTENNA ROD
(a) Insert the cable of the rod until it reaches the bottom.HINT:
wWhen inserting the cable, the teeth on the cable must
face toward the rear of the vehicle.
w Insert the cable approx. 400 mm (15.75 in.).
(b) Wind the cable to retract the rod by turning the ignition switch
to ºLOCKº position.
HINT:
w If the ignition switch is already in ºLOCKº position,
perform step 1.
w In case the cable is not wound, twist it as shown in the
illustration.
w Even if the rod has not retracted fully, install the ant enna
nut and inspect the antenna rod operation. It will finally
retract fully.
(c) Inspect the antenna rod operation by pushing the radio wave
band select buttons.
MOTOR ANTENNA INSPECTION
1. INSPECT MOTOR ANTENNA (Circuit)
Disconnect the motor antenna connector from the body wire
harness and inspect the connector on body wire harness side
as shown.
 Check for Tester connection\
\
Condition Specified value
 Continuity 7±Ground\
\
Constant Continuity
 Voltage 3±Ground\
\
Constant Battery positive voltage
 
g
 8±Ground Ignition switch ACC or ON Battery positive voltage
  8±Ground 
g
position LOCK No voltage
  6±Ground Ignition switch ON Battery positive voltage
  6±Ground 
g
position ACC or LOCK No voltage
  2±Ground Ignition switch Radio or Tape or CD switch ON Battery positive voltage
  2±Ground 
g
ACC or ON Radio or Tape or CD switch OFF No voltage
  5±Ground Ignition switch Radio switch ON Battery positive voltage
  5±Ground 
g
ACC or ON Radio switch OFF No voltage
  
4±Ground
 Ignition switch
ACC or ON and
 AM or FM (87.9 ± 96.0 MHz) Battery positive voltage
  4±Ground ACC or ON and
radio switch ON Others No voltage
 


 

1±Ground
 

Ignition switch
ACC or ON and 

AM
 

Battery positive voltage
   radio switch ON Others No voltage
If circuit is not as specified, inspect radio or wire harness. If
circuit is as specified, replace motor antenna.
±
BODY ELECTRICAL SYSTEM AUDIO SYSTEMBE±215
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
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BODY ELECTRICAL SYSTEM AUDIO SYSTEMBE±219
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8RadioRECEPTION POOR
Antenna cord faulty.Poor signals, poor location.
Problem with radio wave signals or location?
Go to No. 32. Check if antenna cord is OK?
Radio receiver assembly faulty.
9RadioPRESET MEMORY DISAPPEARS
Wire harness or connector faulty.
Radio receiver assembly faulty. Is terminal A4 of radio receiver assembly
properly connected?
BE±232±
BODY ELECTRICAL SYSTEM AUDIO SYSTEM
WhereEverybodyKnowsYourName

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±
BODY ELECTRICAL SYSTEM AUDIO SYSTEM
WhereEverybodyKnowsYourName

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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Open the driver's door
(Other doors remain closed).
Using the door lock control switch, perform
ªlock, unlockº
*1 operation 10 times with in
30 seconds.
Soon (less than 2 secs.) after performing
the above, continue to press the transmitter
switch for 10 seconds. How many times does ªlock, unlockº *1 op-
eration of all doors occur during the time the
transmitter is operated (approx. 10 secs.)? Malfunction on vehicle side
(Proceed to Matrix Chart of Problem
Symptom on page
BE±454).
Wrong transmitter parts (exclusive code
does not match).
[Replace transmitter and ROM in ECU.
(See page BE±449)]
Transmitter fault
(Inspect transmitter on page BE±447).
Close all doors.
Tune the FM radio to 94.9 MHz.
Inspect transmitter (See page BE±447).
Do all doors lock and unlock?
Is there noise on the radio while the trans-
mitter switch is being pushed? *2 Malfunction on antenna curcuit
(Inspect antenna circuit on page
BE±448).
Malfunction on vehicle side
(Proceed to Matrix Chart of Problem
Symptom on page BE±454).
3 times
2 timesDoes not
operate
YESYES
NO
NO Once

Disconnect the antenna cable from the ECU, directly insert
the transmitter (grooved section of key) and press the trans-
mitter switch. In this case do not let the transmitter come in
contact with the ECU case (because the transmitter will be
grounded).
PRECHECK TYPE II
Perform this check in cases where the wireless door lock control system fails t\
o operate anywhere.
*1: Performing lock and unlock once counts as one time.
*2: In some localities, inspection cannot be carried out because the local FM \
radio broadcast is also at 94.9 MHz. When this occurs, perform inspection using a portable radio in a place \
indoors free from the influence
of FM broadcasts.
BE±446
±
BODY ELECTRICAL SYSTEM Wireless Door Lock Control System
WhereEverybodyKnowsYourName

Description
The power source supplies power to each of the vehicle's electrical devices. It is composed of the battery, fuses
and relays, which are located centrally at relay block No. 2 and relay block No. 6 i\
n the engine compartment
and junction block No. 1 relay block No. 4 and relay block No. 5 in the \
cabin near the driver's feet.
Related systems for each Fuse
No.Part NameRelated Systems or Parts
1IGN
Charging System
AIR±BAG System1IGN
Engine
2ST
Starter
3WIPER
Wiper and Washer System
4HTR
Defogger System
A/C System
5ENGINE
Charging System
6RADIO NO. 2
Audio System
Power Mirror System

Cigarette Lighter
A/C System
7CIG
Combination Meter System
AIR±BAG System7CIG
Shift Lock System
Theft Deterrent System

TEL System
8STOP
Stop Light System
Cruise Control System
9TURN
Turn Signal and Hazard
Warning Light System
Cornnering Light System
10MIR HTR
Mirror Heater System
11PANEL
Illumination Light System
12ECU±B
Combination Meter System
AIR±BAG System

Combination Meter System
ECT System
13GAUGE
Back±Up Light
Transmission Indicator

Light Failare Sensor
ABS and TRAC

Power Seat System
Door Lock Control System

TEL System
Shift Lock System
14ECU±IG
Radiator Fan
Auto Antenna

Electric Tension Reducer System
Power Steering

Auto±Tilt away Steering
Cruise Control System
15TAIL
Taillight System
Side Marker15TAIL
Clearance Light
16DOOR
Power Seat System
Luggage Door Opener16DOOR
Door Lock Control System
Fuel Lid Opener System
17IG SWUpstream of ECU±IG, ENGINE, WIP, HTR, TURN, GAUGE, and ST Fuse
18PWR
Power Window System
Sliding Roof System
19ABS NO. 1
ABS and TRAC
20AM1Upstream of MIR HTR, TAIL, PANEL, STOP, ECUA±B, DOOR and PWR Fuse
21ALTUpstream of DEF, HTR, AM1, and ABS No. 1 Fuse
BE±18±
BODY ELECTRICAL SYSTEM Power Source
WhereEverybodyKnowsYourName

4. REMOVE CUP HOLDERUsing a screwdriver, pry out the rear side of the cup holder.
Remove the cup holder.
5. REMOVE UPPER REAR CONSOLE PANEL Using a screwdriver, pry out the console panel.
6. REMOVE UPPER CONSOLE PANEL (a) Remove the six mounting screws.
(b) Using a screwdriver, pry out the console panel.
7. REMOVE RADIO (a) Remove the five mounting bolts.
(b) Disconnect the wiring connectors and antenna cable,
and remove the radio.
8. DISCONNECT SUB±OXYGEN SENSOR CONNECTORS FI±119
EFI SYSTEM
± Electronic Control System (Sub±Oxygen Sensors)
WhereEverybodyKnowsYourName