LEXUS SC400 1991 Service Repair Manual

76
ENGINE CONTROL
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
A 926F1530K 329
C 326F1630N 127C13B28I 127O 327
C14A28I 227O 427C2328I 627O 831
D1326I 727P2027E 226I 827S 327
E 326I 927S1229E 9A28I1027T 227
E10B28I1127T 629E11A28I1529V 127
E12B28K 127V 227F 926K 227V 327
: RELAY BLOCKS
CODESEE PAGERELAY BLOCKS (RELAY BLOCK LOCATION)
219ENGINE COMPARTMENT LEFT
423LEFT KICK PANEL (J/B NO.1 LEFT)
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODESEE PAGEJUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)
1B20ENGINE ROOM MAIN WIRE
1E20INSTRUMENT PANEL WIRE1H1I20COWL WIRE1J20COWL WIRE
1K3A23INSTRUMENT PANEL WIRE3D23INSTRUMENT PANEL WIRE
: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS
CODESEE PAGEJOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)
EB134ENGINE WIRE AND ENGINE ROOM MAIN WIRE (FRONT SIDE OF R/B NO 2)EB234ENGINE WIRE AND ENGINE ROOM MAIN WIRE (FRONT SIDE OF R/B NO.2)
IE136ENGINE ROOM MAIN WIRE AND COWL WIRE (R/B NO. 4)
IG236INSTRUMENT PANEL WIRE AND COWL WIRE (R/B NO. 5)IG338INSTRUMENT PANEL WIRE AND COWL WIRE (RIGHT KICK PANEL)
IH136COWL NO. 2 WIRE AND COWL WIRE (BEHIND COMBINATION METER)II136ENGINE WIRE AND A/C WIRE (BEHIND GLOVE BOX)
IJ136ENGINE WIRE AND COWL WIRE (RIGHT KICK PANEL)IJ236ENGINE WIRE AND COWL WIRE (RIGHT KICK PANEL)
IK136ENGINE WIRE AND INSTRUMENT PANEL WIRE (RIGHT KICK PANEL)IK236ENGINE WIRE AND INSTRUMENT PANEL WIRE (RIGHT KICK PANEL)
BT140FLOOR WIRE AND COWL WIRE (LEFT KICK PANEL)BY140INSTRUMENT PANEL WIRE AND FLOOR NO.3 WIRE (RIGHT KICK PANEL)
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATION
EB34FRONT SIDE OF LEFT FENDER
EC34FRONT SIDE OF INTAKE MANIFOLDED34REAR SIDE OF CYLINDER HEAD RH
IF36LEFT KICK PANELIH36UNDER THE ASHTRAY LH
BK40UNDER THE CENTER PILLAR LH
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: SPLICE POINTS
CODESEE PAGEWIRE HARNESS WITH SPLICE POINTSCODESEE PAGEWIRE HARNESS WITH SPLICE POINTS
E15I2238INSTRUMENT PANEL WIREE16I2338INSTRUMENT PANEL WIRE
E1734ENGINE WIREI32E1834ENGINE WIREI3338ENGINE WIREE20I3438ENGINE WIRE
I10I4038INSTRMENT PANEL WIREI1338COWL WIREB1240FLOOR MAIN WIREI1438COWL WIREB1740FLOOR NO.3 WIREI1738INSTRUMENT PANEL WIRE
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78
ENGINE CONTROL
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194
ELECTRIC TENSION REDUCER
1C
6 1I
8
Bb1
7
BX1
18
Bb1
4
BK BL
2 1
2
1
11
12 15 16
22
9
2 1 B±R
B±R
B
B±R
B
B
B±L
B±L
B±Y
BR
W±B
W±B
W±B
W±B
15A
ECU±IG
TE NSI ON
RE DUCER
SOLENOID LH TENSION
RE DUCER
SOLENOID RH
FROM POWER SOURCE SYSTEM
(
SEE PAGE 56 )
DIODE
( FOR TENSION
REDUCER )
POWER SEAT ECU
(FOR PASSENGER' S SEAT )
BUCKLE
SW LH BUCKLE
SW RHPC SSR± GND
PD
T1 8 T19
D3 P12
B4 B5
Ba2
6 Ba1
11
12
Ba2
5 (
W/ MEMORY POWER SEAT )
( W/O MEMORY POWER SEAT )
Ba1 (W/O MEMORY POWER SEAT )
(
W/ MEMORY POWER SEAT )
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195
B 4 BUCKLE SW LH
1±2 : CLOSED WITH DRIVER'S LAP BELT IN USE
B 5 BUCKLE SW RH
1±2 : CLOSED WITH PASSENGER'S LAP BELT IN USE
T18, T19 TENSION REDUCER SOLENOID LH, RH
2±GROUND : APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
B 432D 328T1831
B 532P1232T1931
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODESEE PAGEJUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)
1C20FLOOR WIRE
1I20COWL WIRE
: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS
CODESEE PAGEJOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)
BX140FLOOR NO. 3 WIRE AND COWL WIRE (RIGHT KICK PANEL)
Ba142FLOOR WIRE AND FRONT SEAT LH WIRE (UNDER THE FRONT LH SEAT)Ba242FLOOR WIRE AND FRONT SEAT LH WIRE (UNDER THE FRONT LH SEAT)
Bb142FLOOR NO. 3 WIRE AND FRONT SEAT RH WIRE (UNDER THE FRONT RH SEAT)
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATION
BK40UNDER THE CENTER PILLAR LH
BL40UNDER THE CENTER PILLAR RH
12 12
X
912X1516X 12
B 4, B 5 D 3 P 12 T18, T19
ORANGE BLACK
SERVICE HINTS
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1
FOREWORD
This wiring diagram manual has been prepared to provide
information on the electrical system of the 1992 LEXUS SC300.
Applicable models: JZZ31 Series
For service specifications and repair procedures of the above
models other than those listed in this manual, refer to the
following manuals;
Manual Name
Pub. No.
1992 LEXUS SC300 Repair Manual
Volume 1
Volume 2
 1992 LEXUS New Car Features
RM260U1
RM260U2
NCF080U
All information in this manual is based on the latest product
information at the time of publication. However, specifications
and procedures are subject to change without notice.
TOYOTA MOTOR CORPORATION
Servicing vehicles with an SRS AIRBAG (referred to as the airbag in the
remainder of this manual) installed.
When handling airbag components (removal, installation or inspection, etc.)\
,
always follow the directions given in the repair manuals listed above to
prevent the occurrence of accidents and airbag malfunction.
NOTICE
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METER, ANALOGCurrent flow activates a magnetic
coil which causes a needle to
move, thereby providing a relative
display against a background
calibration.
LED (LIGHT EMITTING DIODE)
Upon current flow, these diodes
emit light without producing the
heat of a comparable light.
IGNITION COIL
Converts low±voltage DC current
into high±voltage ignition current
for firing the spark plugs.
1. SINGLE
FILAMENT
GROUND
The point at which wiring attaches
to the Body, thereby providing a
return path for an electrical circuit;
without a ground, current cannot
flow. Current flow causes a headlight
filament to heat up and emit light.
A headlight may have either a
single (1) filament or a double (2)
filament.
BATTERY
Stores chemical energy and
converts it into electrical energy.
Provides DC current for the auto's
various electrical circuits.
CAPACITOR (Condenser) A small holding unit for temporary
storage of electrical voltage.
CIRCUIT BREAKER Basically a reusable fuse, a circuit
breaker will heat and open if too
much current flows through it. Some
units automatically reset when cool,
others must be manually reset.
DIODE A semiconductor which allows
current flow in only one direction.
DIODE, ZENER A diode which allows current flow
in one direction but blocks reverse
flow only up to a specific voltage.
Above that potential, it passes the
excess voltage. This acts as a
simple voltage regulator.
FUSE A thin metal strip which burns
through when too much current
flows through it, thereby stopping
current flow and protecting a
circuit from damage.
FUSIBLE LINK A heavy±gauge wire placed in
high amperage circuits which
burns through on overloads,
thereby protecting the circuit.
The numbers indicate the cross±
section surface area of the wires. HORN
An electric device which sounds a
loud audible signal.
LIGHT Current flow through a filament
causes the filament to heat up
and emit light.
METER, DIGITAL Current flow activates one or
many LED's, LCD's, or fluorescent
displays, which provide a relative
or digital display.
MOTOR A power unit which converts
electrical energy into mechanical
energy, especially rotary motion.
CIGARETTE LIGHTER
An electric resistance heating
element.
DISTRIBUTOR, IIA Channels high±voltage current
from the ignition coil to the
individual spark plugs. 2. DOUBLE
FILAMENT
HEADLIGHTS
FUEL
(for High Current Fuse or
Fusible Link)
(for Medium Current Fuse)
M
16
GLOSSARY OF TERMS AND SYMBOLS
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17
1. NORMALLYOPENOpens and
closes circuits,
thereby
stopping (1) or
allowing (2)
current flow.
RESISTOR An electrical component with a
fixed resistance, placed in a circuit
to reduce voltage to a specific
value.
RESISTOR, TAPPED A resistor which supplies two or
more different non±adjustable
resistance values.
SENSOR (Thermistor) A resistor which varies its
resistance with temperature.
SHORT PIN Used to provide an unbroken
connection within a junction block.
SOLENOID An electromagnetic coil which
forms a magnetic field when
current flows, to move a plunger,
etc. SWITCH, DOUBLE THROW
A switch which continuously
passes current through one set
of contacts or the other.
SWITCH,
IGNITION A key operated switch with
several positions which allows
various circuits, particularly the
primary ignition circuit, to
become operational.
Wires are always
drawn as straight lines
on wiring diagrams.
Crossed wires (1)
without a black dot at
the junction are not
joined; crossed wires
(2) with a black dot or
octagonal (
) mark at
the junction are spliced
(joined) connections.
RELAY, DOUBLE THROW
A relay which passes current
through one set of contacts or the
other.
SENSOR, ANALOG SPEED Uses magnetic impulses to open
and close a switch to create a
signal for activation of other
components. TRANSISTOR
A solidstate device typically used
as an electronic relay; stops or
passes current depending on the
voltage applied at ªbase.º
SWITCH, WIPER PARK
Automatically returns wipers to
the stop position when the wiper
switch is turned off.
SWITCH, MANUAL SPEAKER
An electromechanical device
which creates sound waves from
current flow.
2. NORMALLY CLOSED
RESISTOR, VARIABLE OR
RHEOSTAT A controllable resistor with a
variable rate of resistance.
Also called a potentiometer or
rheostat.
2. NORMALLY
OPEN
RELAY
1. NORMALLY
CLOSED Basically, an electrically
operated switch which may
be normally closed (1) or
open (2).
Current flow through a
small coil creates a
magnetic field which either
opens or closes an
attached switch.
(2) SPLICEDWIRES
(1) NOT CONNECTED
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236
GROUND POINT
FRONT TURN SIGNAL
LIGHT LH
ENGINE HOOD
COURTESY SW
TRACTION PUMP AND
MOTOR
HEATER RELAY
ABS ACTUATOR RELAY
TELEPHONE
TRANSCEIVER
AND SPEAKER RELAY
ENGINE OIL LEVEL
WARNING SW
COMBINATION METER
(E1 )
EFI ECU
TRACTION ECU
CHECK CONNECTOR
(
E1 ) CORNERING LIGHT LH
FRONT SIDE MAKER
LIGHT LH
BRAKE FLUID LEVEL
SW
FRONT CLEARANCE
LIGHT LH
FRONT SIDE MAKER
LIGHT RH
FRONT CLEARANCE
LIGHT RH
ABS ACTUATOR
FRONT TURN SIGNAL
LIGHT RH
CRUISE CONTROL
ACTUATOR
OXYGEN SENSOR SUB
(
FOR USA SPEC. )
TDCL (
E1 )
WASHER LEVEL SW EFI MAIN RELAY
CORNERING LIGHT RH
A/C PRESSURE SW
(HI GH PRESSURE )
AIR FLOW METER POWER STERRI NG
PRESSURE SW
NOISE FI LTER
(
FOR IGNI TION SYSTEM ) E4
E10
E12 2
2
BS1 4 E4
E7
E1 E5
EB EA I23
I33
E1 6
I32
E20
E20
E20
IK2 24
ED EC IK1
1 BY1
5
W±B
W±B
W±B
W±B
W±B
W±B
W±B
W±B
W± B W±B
W±B
W±B
W±B
W±B
W±B
W±B
W±B
W±B
W±B
W±B
W±B BR
BR
W±B BR
BR
BR
W±B BR
BR±B BR BR
BR
BR
W± B
W± B
W± B
W± B
W± B
W± B
W± B
W±B
W±B
BR
BR
BR
BR BR
BR
BR
W±B
BR BR
BR
( EO1 )
( E11 )
( E1 )
( EO2 )
I27BR
(
S1 )
( E1 )
NOISE FILTER (
FOR
IGNITION SYSTEM )W±B
W/ TRACTION SYSTEM
NOI SE FILTER
(
FOR DEFOGGER SYSTEM )
W±B
W±B
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237
GLOVE BOX LIGHT SW
CIGARETTE LIGHTER
LUGGAGE COMPARTMENT
DOOR OPENER SW
COMBINATION METER
(EP )
O/D MAIN SW
RHEOSTAT
DO OR LOCK MOTOR,
DOOR UNLOCK
DETECTION SW AND
DOOR OPEN DETECTION
SW LH
MIRROR HEATER LH DOOR KEY LOCK AND
UNLOCK SW LH
POWER WINDOW
MASTER SW
RE MOTE CO NTROL
MIRROR SW
KEY INTER LOCK
SOLENOID
[IGNITION SW]
UNLOCK WA RNING SW
[IGNITION SW]
TURN SIGNAL SW
[COMB. SW]
WIPER AND WASHER SW
[COMB. SW]
LIGHT CONTROL SW
[COMB. SW]
DIMMER SW
[COMB. SW] INTEGRATION RELAY POWER MAIN RELAY HA ZARD S W A/C CONTROL
ASSEMBLY A/T INDICATOR LIGHT
(
FOR SHIFT LEVER )
SEAT HEATER SW TRACTION CUT SW AND
SEAT HEATER SW SHIFT LOCK ECU
3G 8
3F 8
3F 7
3D 10
3D 9
3A 2
1F 6
1K 6 3H
15
3H 14
3H 3
1D 10
1G 3
1G 4
IF
IG 1E
18 3A
1
W±B W±B W±B
W±B
W±B
W±B W±B W±B
W±B W±B
W±B W±B W±B W±B
W±B W±B
W±B W±B
W±B
W±B
W±B
CE NTER AI RB AG
SENSOR ASSEMBLY
I29
W±B
W±B
3G
3
I38 I8 1K 5
WIPER MOTOR
SEAT HEATER RELAY
KICK DOWN SW
THEFT DETERRENT
AND DOOR LOCK ECU
HE ADLIGHT HI RH
HE ADLIGHT HI LH
COMBINATION METER
(
HIGH BEAM )
CRUISE CONTROL SW
[COMB. SW] E3
I1
4
4
1K
12
IE1
11
IH11
CRUISE CONTROL ECU
( GND ) 1J
1
I7
1G1
8
I5 W±B
W±B
W±B
W±B
W±B
W±B
W±B
W±B R
W±B
W±B W±B W±B W±B W±BW±BW±B
W±B W±B W±B
W±B W±B
W±B
W±B
W±B
W±B
W±B W±B
W±B
W±B
IQ1 10
W±B
(E1 )
( E2 )
TILT AND POWER
TELESCOPIC ECU
( GND2 )
W±B ( A/T )
( M/T )
W±B
1H 13
I38
B4
B31
MOO N ROOF CO NTROL
RE LAY
MOON ROOF LIMIT SW
MOO N ROOF MOTOR
MOO N ROOF CO NTROL
SW
PERSONAL LIGHT
VANITY LIGHT LH
VANITY LIGHT RH
PERSONAL LIGHT
VANITY LIGHT RH
VANITY LIGHT LH B3
B1
B1
B2
B
W±B B
W±B
W±B
W±B
W±B
W±B
W±B
W±B W±BW±B
BZ1
4 BZ1
5
B
W±B
W±B
( CANADA )
W±B
( W/O MOON ROOF )(
W/ MOON ROOF )
(
W/O MEMORY MIRROR )
W±B
(
CANADA )
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