radio antenna LEXUS SC300 1991 Service User Guide

9. INSPECT HEATER RESISTANCE OF SUB±OXYGEN
SENSORS
Using an ohmmeter, measure the resistance between the ter-
minals +B and HT.
Resistance: 5.1±6.3
at 20 °C (68 °F)
If the resistance is not as specified, replace the sensor as
follows:
w Disconnect the grommet from the floor panel, and
pull out the wire of the sub±oxygen sensor from the
floor panel.
w Remove the sub±oxygen sensor.
w Install a new sub±oxygen sensor.
Torque: 44 N Vm (450 kgf Vcm, 33 ft Vlbf)
w Run the wire of the sub±oxygen sensor through the
hole in the floor panel.
10. RECONNECT SUB±OXYGEN SENSOR CONNECTORS
11. REINSTALL RADIO (a) Connect the wiring connectors and antenna cable.
(b) Install the radio with the five bolts.
12. REINSTALL UPPER REAR CONSOLE PANEL (a) Fit the console panel to the console box with five clips.
(b) Install the console panel with the six screws.
FI±120
EFI SYSTEM
± Electronic Control System (Sub±Oxygen Sensors)
WhereEverybodyKnowsYourName

IF VEHICLE IS EQUIPPED WITH MOBILE
RADIO SYSTEM (HAM, CB, ETC.)
The ECU has been designed so that it will not be affected by out-
side interference. However, if your vehicle is equipped with a CB
radio transceiver, etc. (even one with about 10 W output), it may,
at times, have an effect upon ECU operation, especially if the an-
tenna and feeder are installed nearby.
Therefore, observe the following precautions:
1. Install the antenna as far away as possible from the ECU. The ECU is located on the floor panel on the passenger side
so the antenna should be installed at the rear of the vehicle.
2. Keep the antenna feeder as far away as possible from the ECU wires±at least 20 cm (7.87 in.) ±and, especially, do not
wind them together.
3. Check that the feeder and antenna are properly adjusted.
4. Do not equip your vehicle with a powerful mobile radio
system.
5. Do not open the cover or the case of the ECU unless absolutely necessary. (If the IC terminals are touched, the IC
may be destroyed by static electricity.)
AIR INDUCTION SYSTEM
1. Separation of the engine oil dipstick, oil filler cap, PCV hose,
etc. may cause the engine to run out of tune.
2. Disconnection, looseness or cracks in the parts of the air
induction system between the throttle body and cylinder
head will cause air suction and cause the engine to run out
of tune.
ELECTRONIC CONTROL SYSTEM
1. Before removing EFI wiring connectors, terminals, etc., firstdisconnect the power by either turning the ignition switch
OFF or disconnecting the battery terminals.
HINT: Always check the diagnosis code before disconnecting
the battery terminals.
2. When installing the battery, be especially careful not to
incorrectly connect the positive (+) and negative (±) cables.
3. Do not permit parts to receive a severe impact during removal or installation. Handle all EFI parts carefully, especially the
ECU.
4. Do not be careless during troubleshooting as there are numerous transistor circuits and even slight terminal contact
can cause further troubles.
5. Do not open the ECU cover.
6. When inspecting during rainy weather, take care to prevent entry of water. Also, when washing the engine compartment,
prevent water from getting on the EFI parts and wiring
connectors.
7. Parts should be replaced as an assembly.
FI±12
±
EFI SYSTEM Inspection Precautions
WhereEverybodyKnowsYourName

IF VEHICLE IS EQUIPPED WITH MOBILE
RADIO SYSTEM (HAM, CB, ETC.)
The ECU has been designed so that it will not be affected by out-
side interference. However, if your vehicle is equipped with a CB
radio transceiver, etc. (even one with about 10 W output), it may,
at times, have an effect upon ECU operation, especially if the an-
tenna and feeder are installed nearby.
Therefore, observe the following precautions:
1. Install the antenna as far away as possible from the ECU. The
ECU is located on the floor panel on the passenger side so
the antenna should be installed at the rear of the vehicle.
2. Keep the antenna feeder as far away as possible from the ECU wires±at least 20 cm (7.87 in.)±and, especially, do not
wind them together.
3. Check that the feeder and antenna are properly adjusted.
4. Do not equip your vehicle with a powerful mobile radio
system.
5. Do not open the cover or the case of the ECU unless absolutely necessary. (If the IC terminals are touched, the IC
may be destroyed by static electricity.)
AIR INDUCTION SYSTEM
1. Separation of the engine oil dipstick, oil filler cap, PCV hose,
etc. may cause the engine to run out of tune.
2. Disconnection, looseness or cracks in the parts of the air induction system between the throttle body and cylinder
head will cause air suction and cause the engine to run out
of tune.
ELECTRONIC CONTROL SYSTEM
1. Before removing EFI wiring connectors, terminals, etc., firstdisconnect the power by either turning the ignition switch
OFF or disconnecting the battery terminals.
HINT: Always check the diagnosis code before disconnecting
the battery terminals.
2. When installing the battery, be especially careful not to
incorrectly connect the positive (+) and negative (±) cables.
3. Do not permit parts to receive a severe impact during removal or installation. Handle all EFI parts carefully, especially the
ECU.
4. Do not be careless during troubleshooting as there are numerous transistor circuits and even slight terminal contact
can cause further troubles.
5. Do not open the ECU cover.
6. When inspecting during rainy weather, take care to prevent entry of water. Also, when washing the engine compartment,
prevent water from getting on the EFI parts and wiring
connectors.
7. Parts should be replaced as an assembly. FI±13
EFI SYSTEM
± Inspection Precautions
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

9. INSPECT HEATER RESISTANCE OF SUB±OXYGEN
SENSORS
Using an ohmmeter, measure the resistance between the ter-
minals +B and HT.
Resistance: 5.1±6.3
at 20 °C (68 °F)
If the resistance is not as specified, replace the sensor as
follows:
w Disconnect the grommet from the floor panel, and
pull out the wire of the sub±oxygen sensor from the
floor panel.
w Remove the sub±oxygen sensor.
w Install a new sub±oxygen sensor.
Torque: 44 N Vm (450 kgf Vcm, 33 ft Vlbf)
w Run the wire of the sub±oxygen sensor through the
hole in the floor panel.
10. RECONNECT SUB±OXYGEN SENSOR CONNECTORS
11. REINSTALL RADIO (a) Connect the wiring connectors and antenna cable.
(b) Install the radio with the five bolts.
12. REINSTALL UPPER REAR CONSOLE PANEL (a) Fit the console panel to the console box with five clips.
(b) Install the console panel with the six screws.
FI±120
EFI SYSTEM
± Electronic Control System (Sub±Oxygen Sensors)
WhereEverybodyKnowsYourName

204
AUTO ANTENNA
Bc1
9Bc1 24 Bc1 23 Bc1 8 C
C
D
D
M
3614 11912134
2
1
4
5
8
6
3
78 10
5
2 7
+B IG ACC ANT+B AMP+B ANTB ANTA GND
UP DOWN S VCC SIG SGND
L±YY
R±G
BR
R±W L±B
L±GW±B
IC
SENSOR +
± P±G
P±L
Y±R
L±W
W±B
W±B
8
9
10 4
P±L
P±G
L±Y
B±R
GR
P±GP±L
Y±R
L±W
P±G
P±L
Y±R
L±W
RADIO AND TAPE RLAYER
AUTO ANTENNA MOTOR AND RELAY A3 2
B
G
R
L
B±Y
FROM POWER SOURCE SYSTEM
(
SEE PAGE 56 )
12 1 2
3
AUTO ANTENNA CONTROL RELAY
AUTO ANTENNA MOTOR
BM
2
7
1C
61E 10 C
3
A 3
A 8
A 1
B
10
B4
BV1
7
BV1
18
BV1
4
BV1
19
Bc1
10
Bc2
1 IE 1
2
IG2
3
IQ2
11
BV2
7 BV1 2IQ1
3
I31
L±Y
L±Y
L±Y
L±Y
L±Y
GR
GR
GR
GR
GR
GR R2 ,R4 ,R5
D
BAC
(
W/ CD PLAYER )
( W/O CD PLAYER )
8
A
B
A32
20A
RADIO
NO. 1 15A
ECU±IG
7. 5A
RADIO
NO. 2 GR
( W/O CD PLAYER )
( W/ CD PLAYER )
GR
( W/ CD PLAYER )
(W/O CD PLAYER )
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4
XXXX10 4
XXXX10
BDB
R2 R2
A32
12 3
45678 A
A32
13
8X A
R4
3
89
C
R5
X23 456
7891011121314
205
A32 AUTO ANTENNA MOTOR AND RELAY
3±GROUND : ALWAYS APPROX. 12 VOLTS
6±GROUND : APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION
8±GROUND : APPROX. 12 VOLTS WITH IGNITION SW AT ACC OR ON POSITION
7±GROUND : ALWAYS CONTINUITY
R 4(A), R 5(C) RADIO AND PLAYER
(A) 3, (C) 3±GROUND : APPROX. 12 VOLTS WITH IGNITION SW AT ACC OR ON POSITION
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
A32A30R2A29 (W/ CD PLAYER)R 4B29 (W/ CD PLAYER)A32B30R 2D29 (W/O CD PLAYER)R 5C29 (W/O CD PLAYER)
: RELAY BLOCKS
CODESEE PAGERELAY BLOCKS (RELAY BLOCK LOCATION)
219ENGINE COMPARTMENT LEFT
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODESEE PAGEJUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)
1C20FLOOR WIRE
1E20INSTRUMENT PANEL WIRE
: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS
CODESEE PAGEJOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)
IE136ENGINE ROOM MAIN WIRE AND COWL WIRE (R/B NO. 4)
IG236INSTRUMENT PANEL WIRE AND COWL WIRE (R/B NO. 5)
IQ138INSTRUMENT PANEL WIRE AND CONSOLE BOX WIRE (UNDER THE INSTRUMENT PANEL CENTER)IQ238INSTRUMENT PANEL WIRE AND CONSOLE BOX WIRE (UNDER THE INSTRUMENT PANEL CENTER)
BV140FLOOR NO 3 WIRE AND CONSOLE BOX WIRE (UNDER THE INSTRUMENT PANEL CENTER)BV240FLOOR NO. 3 WIRE AND CONSOLE BOX WIRE (UNDER THE INSTRUMENT PANEL CENTER)
Bc140FLOOR NO 3 WIRE AND FLOOR WIRE (UNDER THE LEFT SIDE OF REAR SEAT CUSHION)Bc240FLOOR NO. 3 WIRE AND FLOOR WIRE (UNDER THE LEFT SIDE OF REAR SEAT CUSHION)
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATION
BM40BACK PANEL CENTER
: SPLICE POINTS
CODESEE PAGEWIRE HARNESS WITH SPLICE POINTSCODESEE PAGEWIRE HARNESS WITH SPLICE POINTS
I3138CONSOLE BOX WIRE
SERVICE HINTS
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1234
19 LEXUS SC300
4ACC
IG1
ST1
AM1 3
2
3BV1
2 BV2 1 BV2 6 IQ2 7 I Q2 4 BV2 3 BV2 10 BV2 9 BV2 6 BV1 5 BV1 4 BV1
10 I F2 1 IF22IG2 1IG2 11Bc2 12Bc2
10 BV1
11 IQ2 3 IQ1
7 BV2 2 BV1 19 BV1 7 BV1 18 BV1
3IG2
1Bc2
10 Bc 1
9Bc1
8Bc1
23 Bc1
8 BV2
12 IQ2 24 Bc 1
II BM 1J
5
1J
8
2
1C
6
1E
10
2
1B
4 1J
7
AMP E
MU TE A MP RU ± RU +
7A
10 C
4C
8A
3A
4A
3D
1D
6D
2D
3C
1A
6 5A 2A 6A 1B 3B 2B 6B 1C 5C 9C 2C
74
MU TE
AMP
RU±
RU+
RL±
RL +
RR±
RR+
FL±
FL+
FR±
FR+ TLMT PWR VOL+ VOLC SGND B ACC ANT ANTA ANTB WP+ WP± ACC +B E ANTB ANTA ANT ACC B IG
6
3
8
5
2
1
7
3
4
9
10
26 5 1 47
B
W
P±L
R± B BR
R± B P±L
W B Y B
W R
V
V
V
R
W B
Y
B
W
P±L
BR
BR P± L
W± B Y± R
L±W
P±G GR
L±Y
B±R
R±W
B±W
GR
L±Y
BR
L±Y
GR L±Y
GR
P± G
L±W Y±R L±Y
G±RL±YGR
P± G
L±W Y±R
Y±R
L±WP±G GR
L±Y L±Y W
P±L
VV
G±RR±L
R± W G± Y W
W± L W
LG L
P
P
P
P
V LG
L W
BR
BR
B±Y
P±L
B±Y
E
1 11 2
2 22 1
60A MAIN
100A AM1
120A ALT
40A
IGSW I15
IGNITION SW
BATTERY 20A
RADIO No. 1
7. 5A
RA DI O No. 2
RADIO AND PLAYER
F9
FUSE BLOCK A3 2
AUTO ANTENNA MOT OR AND REL AY
W1 0
WOOF ER SPEAKER
AMPLIFIER
W9
WOOFER
SPEAKER
R12
REAR
SPEAKER LH
R13
REAR
SPEAKER RH
F1 0
FRONT DOOR
SPEAKER LH
15A
ECU±I G
To Telephone Tr ans ceiv er
and Speaker Relay
< 18±7>
To A/ C Cont rol Sw
and Radio Sw
< 22±4>
To A/ C Cont rol Sw
and Radio Sw
< 22±4>
To Telephone Transc eiver
and Speak er Relay
< 18±7>
Power
Source
Radio and Player
(
w/ o CD Player )
Auto Antenna
2IE1L±Y
( SHI ELDED )
P± L (
SHI EL DED )
R2 ,R3 ,R5 , R6
CDA B 12
5
34
678910 12
3456
12 34
5678910 12
3456
CD A B
R2 R3 R5 R6 RADIO AND PLAYER
L±Y
GR
3
4
Under the
as htr ay RHBack panel
center
8
7
BR
Y B
WhereEverybodyKnowsYourName

567 8
20 LEXUS SC300(
Cont ' d )
2
MUTE
5 RU±1
RU+
9
WF±
10WF+
6
AMP 8
GN D 3
B 4
ACC 7
E 6 BV2 5 BV2 2 IG2 1 IG2
11 BC2 12 BC2
10 IF2 1 IF2
6 IQ2 7 IQ2
1B FR+ 2B
FL +
5B
FR± 6B
FL ± 3B
RR+ 4B
RR± 8B
RL+ 9B
RL ±
6A AMP
11 ASGND
10 AGND
9ABEEP
3AMU TE
8AR¥
L
7AR¥
R
2AR¥
L
1AF¥
R
7AE
2
12 121
2
1
8 BV2
12 IQ2 II 23 Bc1 9 Bc1
8Bc1 1Bc2 10Bc1 1J
5
1C
6
4
AMP
7E
1
ANTB 2
ANTA 5
ANT3
B 8
ACC 6
IG
24 Bc 1
BM
B±Y
GR
L±Y
L±W B± R
L±G
Y± R
R± BL±B
P±L WB
BR
GY
W
BR L
R L±Y
R± B P± L P± L
BR
BR
P
V
P
V
P
V
P
V
LG
L
P
V
B Y
Y±R
L±W
P± G L±Y GR
B±RGR
L±Y
B±R L±G
Y±R
Y B
W R
P±L
P±L
W± B
BR
BR BR BR
R
L
BR W
Y
G
BR
P±L GR
L±Y
L±W L±B P±L
L±YGR GR
B± Y
To Telephon
Transceiver
and Relay< 18±1>
15A
ECU± I G
W
B
B±W
R± W
W9
WOOFER
SPEAKER
W10 WOOFER SPEAKER
AMPLIFIER STEREO POWER AMPLIFIERR12
REAR
SPEAKER LH
R13
REAR
SPEAKER RH
F10
FRONT DOOR
SPEAKER LH
A32
AUTO ANTENNA MOTOR AND RELAY
Radio and Player(
w/ CD Player )
Auto Antenna
(SHI ELDED )
( SHI ELDED ) (
SHIELDED )
(
PIONEER )
( PIONEER )
P± L
(NAKAMICHI )
( PI ONEER )
(
PIONEER )
BR±B
S13 , S14 AB
6
4
3
2
1
7 8 9 10 11 12 14 5
13
12
5 34
678910 A
B
STEREO POWER
AMPLIFIER
S1 3
S1 4
P±L L±B
Under the
as htr ay RH Back panel c ent er
(
PIONEER )
10 B 14 AL±YGR+B ACC
L±Y
GR
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244
Rear Window Defogger
and Mirror Heater
Remote Control Mirror
Seat Heater
Shift Lock
SRS AIRBAG
Starting
Taillight and
Stop Light
Theft Deterrent and
Door Lock Control
Turn Signal and Hazard
Warning Light
Wiper and Washer
Wireless Door Lock
Remote Control
Horn
Ignition
Illumination
Interior Light
Liquid Crystal Inner
Rear View Mirror
Moon Roof
Power Seat
(Driver's)
Power Source
Power Window
PPS (Progressive
Power Steering
Radio and Player
ABS and
Traction Control
Automatic
Air Conditioner
Auto Antenna
Back±Up Light
Cellular Mobile
Telephone
Charging
Cigarette Lighter
Combination Meter
Cruise Control
Headlight and Light Auto
Turn Off (for USA)
Headlight
(for Canada) ECT and
A/T Indicator
4±2 16±2 7±2
3±2 21±2 3±8
14±4
18±2 19±4 (w/o CD Player)
20±8 (w/ CD Player)9±2 8±2
4±7 (for USA)
5±7 (for Canada)11±2
12±311±5 (w/ Driving
Position Memory)11±7 12±1 1±5 13±2
6±2 15±2 14±2
13±2
17±7 7±3 17±2 15±3
1±315±2
Power Tilt and
Power Telescopic12±2
Power Seat (Passengerºs
and Electric Tension Header
5±2 2±2
Cornering Light ABS (Anti±Lock
Brake System)
22±2
Engine Control Unlock and Seat
Belt Warning
1±2
23±2 (w/o Driving
Position Memory)
1 23±119±2 (w/o CD Player
20±2 (w/ CD Player
14±310±2 (w/ Memory)
5±7 (w/o Memory)
4±3 (for USA)
5±3 (for Canada) 4±5 (for USA)
5±5 (for Canada)
OVERALL ELECTRICAL WIRING DIAGRAM
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