stop start LEXUS SC300 1991 Service User Guide

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

Inspection of Power Source Circuit
INSPECTION OF JUNCTION BLOCK NO. 1
1. INSPECT FUSE CIRCUITRemove the fuse from the junction block and inspect the con-
nector on junction block side as shown.
FuseCheck forTester connectionConditionSpecified value
IGNVoltage1±GroundIgnition switch turned to ONBattery voltage
ST
g
4±GroundIgnition switch turned to START
yg
WIPER5±GroundIgnition switch turned to ON
HTR8±Ground
g
ENGINE9±Ground
RADIO NO. 211±GroundIgnition switch turned to ACC or ON
CIG14±Ground
g
STOP15±GroundConstant
TURN18±GroundIgnition switch turned to ON
MIR HTR20±GroundIgnition switch turned to ON and defogger
switch turned to ON
PANEL21±GroundLight control switch turned to TAIL or HEAD
and *Engine Running
ECU±B27±GroundConstant
GAUGE29±GroundIgnition switch turned to ON
ECU±IG32±Ground
g
TAIL33±GroundLight control switch turned to TAIL or HEAD
and *Engine Running
DOOR35±GroundConstant
IG SW38±Ground
POWER39±Ground
If the circuit is not as specified, refer to BE±15 wiring diagram
and inspect the circuits connected to other parts.
BE±20
±
BODY ELECTRICAL SYSTEM Power Source
WhereEverybodyKnowsYourName

Parts Replacement ± Stoplights
(Rear Combination Light)
(See page BE±56 )
(High Mount Stop Light)
REPLACEMENT OF HIGH MOUNT STOP
LIGHT
1. REMOVE HIGH MOUNT STOP LIGHT
(a) Disconnect negative (±) terminal from the battery.
CAUTION: Work must be started after approx. 20 se-
conds or longer from the time the ignition switch is
turned to the ºLOCKº position and negative (±) terminal
cable is disconnected from the battery.
(w/o Rear Spoiler)
(b) Separate the woofer speaker cover from package tray
trim.
(c) Disconnect connector.
(d) Remove woofer speaker cover.
(e) Remove five screws and separate the high mount stop light from woofer speaker cover.
(w/ Rear Spoiler)
(f) Separate the rear spoiler from the luggage door. (See page BO±106 )
(g) Remove three screws and separate the high mount stop
light from rear spoiler.
2. INSTALL HIGH MOUNT STOP LIGHT For installation, follow the removal procedure in reverse.
Parts Inspection± Stop Light System
(Stop Light Switch)
STOP LIGHT SWITCH
REMOVAL AND INSTALLATION OF STOP
LIGHT SWITCH
1. REMOVE STOP LIGHT SWITCH
(a) Remove instrument panel subassembly cover underNo.1 and brake pedal return spring.
(b) Disconnect connector.
(c) Remove a nut and switch.
2. ADJUSTMENT OF STOP LIGHT SWITCH (See page BR±4)
3. INSTALL STOP LIGHT SWITCH For installation, follow the removal procedure in reverse.
±
BODY ELECTRICAL SYSTEM Lighting SystemBE±61
WhereEverybodyKnowsYourName

ConnectionCheck forTester connectionConditionSpecified value
A19 A15Trip switch A/BPushContinuity
Trip switchContinuity
A19±A15Trip switch A/BFreeNo continuityTrip switchContinuity
A20 A15Trip switch RESETPushContinuityA20±A15Trip switch RESETFreeNo continuity
DOME
FuseVoltageA11±GroundConstantBattery positive voltage
Speed
SVoltageA13 A15
Ignition
switch
*3 Revolve propeller shaft0V
11 V
SensorVoltageA13±A15switch
ON*3 Stop propeller shaft0V or 11V
C1±GroundPBattery positive voltage
C2±GroundIgnitionRBattery positive voltage
Neutral start
it hVoltageC3±Ground
Ignition
switch
ON andNBattery positive voltageswitchVoltageC4±GroundON and
shift leverDBattery positive voltage
C5±Ground
shift lever
position2Battery positive voltage
C16±Ground
osition
LBattery positive voltage
O/D OFFContinuityC18 GroundO/D OFF switchONContinuity
SwitchContinuityC18±GroundO/D OFF switchOFFNo continuity
AlternatorContinuityC15±GroundEngine stopContinuity
ºLº terminalVoltageC14±GroundEngine runningBattery positive voltage
FuelContinuityA7 GroundFuel remainderFullNo continuity
SenderContinuityA7±GroundFuel remainderEmptyContinuity
GaugeFull, Approx. 79.3 mm
(3.12 in.)Approx. 6

ResistanceA8±C8Float
position1/2, Approx. 193.1 mm
(76.0 in.)Approx. 32.5

Empty, Approx. 308.1 mm
(12.13 in.)Approx. 97

*Window
washer level
ContinuityB9±GroundON (float down)Continuitywasher level
warning
switchContinuityB9 Ground
(Canada)OFF (float up)No continuity
Brake fluidBrake fluid levelON (float down)Continuity
Level warning
Brake fluid level
warning SWOFF (float up)No continuity
SW and
Parking brake
SW
ContinuityC13±GroundParking brake
ON (Depress the Ped-
al))Continuity
SWParking brake
SWOFF (Release the Ped-
al)No continuity
Low oil
PressureContinuityC19 GroundEngine condition
RunningNo continuity
Pressure
Warning SWContinuityC19±GroundEngine conditionStopContinuity
Door courtesyContinuityC12 GroundDriver's andOpen (ON)Continuityy
SwitchContinuityC12±GroundDriver s and
passenger's doorClosed (OFF)No continuity
IGN fuseVoltageC14 GroundIgnition switchONBattery positive voltageVoltageC14±GroundIgnition switchLOCK or ACCNo voltage
CIG fuseVoltageA6 GroundIgnition switchACC or ONBattery positive voltageVoltageA6±GroundIgnition switchLOCK or STARTNo voltage
BE±107±
BODY ELECTRICAL SYSTEM Combination Meter
WhereEverybodyKnowsYourName

4. CHECK THAT PEDAL RESERVE DISTANCE IS CORRECT,
AS SHOWN
Release the parking brake.
With the engine running, depress the pedal and measure the
pedal reserve distance, as shown.
Pedal reserve distance at 490 N (50 kgf, 110.2 lbf):
More than 89 mm (3.50 in.)
If the reserve distance is incorrect, troubleshoot the brake
system.
BRAKE BOOSTER OPERATIONAL TEST
BR03P±0B
1. OPERATING CHECK
(a) Depress the bake pedal several times with the engine off and
check that there is no change in the pedal reserve distance.
(b) Depress the brake pedal and start the engine. If the pedal goes down slightly, operation is normal.
2. AIR TIGHTNESS CHECK
(a) Start the engine and stop it after 1 or 2 minutes. Depress the brake pedal several times slowly. If the pedal goes down the
farthest the 1st time, but gradually rises after the 2nd or 3rd
time, the booster is air tight.
(b) Depress the brake pedal while the engine is running, and stop the engine with the pedal depressed. If there is no
change in the pedal reserve travel after holding the pedal for
30 seconds, the booster is air tight.
BRAKE SYSTEM BLEEDING
BR0ED±04
HINT: If any work is done on the brake system or if air in the
brake lines is suspected, bleed the system of air.
NOTICE: Do not let brake fluid remain on painted sur-
faces. Wash it off immediately.
1. REMOVE RESERVOIR CAP Turn the reservoir cap to the ªopenº side and remove it.
2. FILL RESERVOIR WITH BRAKE FLUID
Fluid: SAE J1703 or FMVSS NO.116DOT3
BR±8±
BRAKE SYSTEM CHECK AND ADJUSTMENT
WhereEverybodyKnowsYourName

TRAC CONTROL SYSTEM BLEEDING
BR0EE±03
1. BLEED TRACTION CONTROL SYSTEMCAUTION:
w The fluid is under high pressure, and could spray out with
great force, so exercise caution.
w When repairing the brake master cylinder or TRAC
system, bleed the air out of the TRAC system.
(a) Connect a vinyl tube to the bleeder plug of accumulator, then
loosen the bleeder plug.
(b) Start the engine to allow the TRAC pump motor to operate
until all the air has been bled out of the fluid.
(c) Tighten the bleeder plug and stop the engine.
Torque: 8.3 N Vm (85 kgf Vcm, 74 in. Vlbf)
(d) C onnect a vinyl tube to the bleeder plug of the TRAC
actuator, then loosen the bleeder plug.
(e) Start the engine to allow the TRAC pump motor to operate
until all the air has been bled out of the fluid.
(f) Tighten the bleeder plug and stop the engine. Torque: 8.3 N Vm (85 kgf Vcm, 74 in. Vlbf)
(g) Check if any diagnostic trouble code is output which indicates
trouble. If there is, clear the diagnostic trouble code.
2. CHECK FLUID LEVEL IN RESERVOIR Check the fluid level and add fluid if necessary.
Fluid:
SAE J1703 or FMVSS NO. 116DOT3
HINT: Add fluid with the engine idling.
BR±10
±
BRAKE SYSTEM CHECK AND ADJUSTMENT
WhereEverybodyKnowsYourName

SPEED SENSOR SIGNAL CHECK
1. Turn the ignition switch to OFF.
2. Using SST, connect terminals Ts and E1 of DLC1.SST 09843±18020
3. Start the engine.
4. Check that the ABS warning light blinks. HINT: If the ABS warning light does not blink, inspect the ABS
warning light circuit (see page BR±144).
5. Drive vehicle straight forward. HINT: Drive vehicle faster than 45 km/h (28 mph) for several
seconds.
6. Stop the vehicle.
7. Using SST, connect terminals Tc and E1 of DLC1.
SST 09843±18020
8. Read the number of blinks of the ABS warning light. HINT: See the list of diagnosis trouble codes shown on the
next page.
If every sensor is normal, a normal code is output (A cycle of
0.25 sec. on and 0.25 sec. OFF is repeated).
If 2 or more malfunction are indicated at the same time, the
lowest numbered code will be displayed 1st.
9. After performing the check, disconnect terminals Ts and E1,Tc and E1 of DLC1, and ignition switch turned off.
BR±80
±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)
WhereEverybodyKnowsYourName

COMPRESSION CHECK
EG21U±02
HINT: If there is lack of power, excessive oil consumption or
poor fuel economy, measure the compression pressure.
1. WARM UP AND STOP ENGINE Allow the engine to warm up to normal operating tempera-
ture.
2. DISCONNECT NEGATIVE TERMINAL CABLE FROM BATTERY
CAUTION: Work must be started after 90 seconds from
the time the ignition switch is turned to the ªLOCKº posi-
tion and the negative (±) terminal cable is disconnected
from the battery.
3. REMOVE INTAKE AIR CONNECTOR
(a) Disconnect the following hoses: (1) Air hose from IAC valve
(2) Air hose (from air control valve on PS pump) from intake
air connector
(b) Remove the bolt holding the intake air connector to the cylinder head cover.
(c) Remove the 2 hose clamps.
(d) Disconnect the intake air connector from the throttle body
and air cleaner hose, and remove the intake air connector.
4. REMOVE UPPER HIGH±TENSION CORD COVER
(a) Remove the 2 bolts.
(b) Disconnect the front side claw groove of the upper cord cover
from the claw of lower cord cover, and remove the upper cord
cover.
±
1UZ±FE ENGINE ENGINE MECHANICALEG±37
WhereEverybodyKnowsYourName

COMPRESSION CHECK
HINT: If there is lack of power, excessive oil consumption or
poor fuel economy, measure the compression pressure.
1. WARM UP AND STOP ENGINE Allow the engine to warm up to normal operating tempera-
ture.
2. REMOVE NO.3 TIMING BELT COVERS (See steps 1, 5 to 10 and 14 on pages EM±11 to 13)
3. DISCONNECT COLD START INJECTOR CONNECTOR
4. DISCONNECT RH CAM POSITION SENSOR CONNECTOR
(a) Disconnect the connector from the ignition coil bracket.
(b) Disconnect the sensor connector.
5. DISCONNECT LH CAM POSITION SENSOR CONNECTOR
6. REMOVE SPARK PLUGS (a) Disconnect the eight high±tension cords from the sparkplugs.
Disconnect the high±tension cords at rubber boot. Do
not pull on the cords.
NOTICE: Pulling on or bending the cords may damage
the conductor inside.
EM±30
±
ENGINE MECHANICAL Compression Check
WhereEverybodyKnowsYourName

INSPECTION OF SUB±OXYGEN
SENSORS
1. INSPECT SUB±OXYGEN SENSORS(a) Cancel diagnostic code. (See TR section)
(b) A llo w th e en g in e to wa rm up to no rma l op e ra tin gtemperature.
(c) Drive for 5 minutes or more between 80km/h (50 mph) and 100 km/h (62 mph) in ºDº range.
(d) Following the conditions in step (c), press fully on the accelerator pedal for 2 seconds or more.
HINT: Do not exceed 100 km/h (62 mph), or diagnostic code
will be cancelled.
(e) Stop the vehicle, and turn the ignition switch to OFF.
(f) Carry out steps (b), (c) and (d) again to test acceleration.
If code No.27 reappears again, check the sub±oxygen sen-
sor circuit. If the circuit is normal, replace the sub±oxygen
sensor.
2. DISCONNECT CABLE FROM NEGATIVE TERMINAL OF BATTERY
CAUTION: Work must be started after approx. 20 se-
conds or longer from the time the ignition switch is
turned to the ºLOCKº position and the negative (±) termi-
nal cable is disconnected from the battery.
3. REMOVE TRANSMISSION SHIFT LEVER KNOB (a) Push down the lever cover.
(b) Remove the two screws and shift lever knob.
(c) Remove the lever cover.
FI±118
EFI SYSTEM
± Electronic Control System (Sub±Oxygen Sensors)
WhereEverybodyKnowsYourName