LEXUS SC400 1991 Service Repair Manual
Manufacturer: LEXUS, Model Year: 1991, Model line: SC400, Model: LEXUS SC400 1991Pages: 4087, PDF Size: 75.75 MB
Page 901 of 4087

Water Temperature
Connector Diagrams (Cont'd)
BE±102±
BODY ELECTRICAL SYSTEM Combination Meter
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Page 902 of 4087

Parts Inspection
(Combination Meter Assembly)
REMOVAL AND INSTALLATION OF
COMBINATION METER ASSEMBLY
1. REMOVE COMBINATION METER ASSEMBLY(a) Lower the steering wheel fully and set it in the far position.
(b) Turn the ignition switch to LOCK and disconnect battery terminals.
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.
(c) Remove instrument cluster finish panel.
(d) Remove four screws and disconnect three connectors.
(e) Remove combination meter assembly.
2. INSTALL COMBINATION METER ASSEMBLY For installation, follow the removal procedure in reverse.
±
BODY ELECTRICAL SYSTEM Combination MeterBE±103
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Page 903 of 4087

DISASSEMBLY OF COMBINATION
METER ASSEMBLY
(Components)
BE±104±
BODY ELECTRICAL SYSTEM Combination Meter
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Page 904 of 4087

1. REMOVE COVER(a) Remove the seven screws.
(b) Remove the cover from the meter case.
2. REMOVE METER GLASS (a) Remove the twelve screws.
(b) Remove the character plate from the meter plate.
3. REMOVE METER PLATE (a) Remove the four screws.
(b) Remove the meter plate from the meter case.
4. REMOVE METER CIRCUIT PLATE (a) Remove the sixteen screws.
(b) Disconnect the two connectors from the meter circuit plate.
(c) Remove bulbs from the meter circuit plate.
(d) Remove the meter circuit plate.
5. REMOVE ODOMETER/TRIP METER Remove the two screws and the odometer/trip meter.
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BODY ELECTRICAL SYSTEM Combination MeterBE±105
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Page 905 of 4087

6. REMOVE CLOCKRemove the two screws and the clock.
7. REMOVE FUEL AND TEMPERATURE GAUGE Release the four lugs, and separate the two gauges from the
meter lens.
ASSEMBLY OF COMBINATION METER
ASSEMBLY
For installation, follow the removal procedure in reverse.
INSPECTION OF COMBINATION METER
ASSEMBLY
1. INSPECT COMBINATION METER WIRING CIRCUITDisconnect connector A, connector B and connector C from
the combination meter and inspect the connectors on the
wire harness side as follows.
BE±106
±
BODY ELECTRICAL SYSTEM Combination Meter
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Page 906 of 4087

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
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Page 907 of 4087

ConnectionCheck forTester connectionConditionSpecified value
Turn signalHazard warning switch ONBattery positiveTurn signal
SW andB 16 Ground
Hazard warning switch ONBattery ositive
voltage e 0V
HazardB±16±Ground
IG SW ON and turn signal SW ºLeftºBattery positive
Warning
Si hVoltage
IG SW ON and turn signal SW ºLeftºBattery ositive
voltage e 0V
SwitchVoltage
Hazard warning switch ONBattery positive
B 17 Ground
Hazard warning switch ONBattery ositive
voltage e 0VB±17±Ground
IG SW ON and turn signal SW ºRightºBattery positiveIG SW ON and turn signal SW ºRightºBattery ositive
voltage e 0V
HeadlightLi ht t l SWDimmer SW ºHIº orBattery positiveHeadlight
VoltageB7±GroundLight control SW
ºHEADº
Dimmer SW HI or
ºFlashº
Battery ositive
voltageVoltageB7±GroundºHEADºDimmer SW ºLOºNo voltage
ContinuityB6±GroundLight control SW
º
HEADº
Dimmer SW ºHIº or
ºFlashºContinuityContinuityB6 GroundºHEADºDimmer SW ºLOºNo continuity
IgniterVoltageA9±GroundEngine RunningVoltage
fluctuates
ECT patternVoltageB4 GroundIG SW ON and ECT patternPWRBattery positive voltageECT attern
Select switchVoltageB4±GroundIG SW ON and ECT attern
select SW positionNORMNo voltage
Engine oilOil temperature below approx. 55 5C (131 5F)Continuityg
Level warn-
ing Switch
ContinuityB8±Ground
Oil temperature
above approx. 55 5CON (float up)ContinuitygContinuityB8 Groundabove a rox. 55 C
(131 5F) and SW
positionOFF (float off)No continuity
GAUGE fuseVoltageA1 GroundIgnition switchONBattery positive voltageVoltageA1±GroundIgnition switch
positionLOCK, ACC, STARTNo voltage
Neutral StartVoltageA12±GroundIgnition switch
position
START (ºPº or ºNº
range)Battery positive voltage
switch
VoltageA12 GroundpositionLOCK, ACC, ONNo voltage
ECU±BVoltageC11 GroundIgnition switchONBattery positive voltage
FuseVoltageC11±GroundIgnition switch
positionLOCK, ACC, STARTNo voltage
Rheostat
Li ht t l
ON (Rheostat knob
t d itiBtt ltLight control
VolumeLight control SWturned any position
except fully clock-
Battery voltage or
5V or moreVolume
VoltageA2±Ground
g
HEAD or TAIL and
rheostat volume
except fully clock-
wise)5V or more
VoltageA2 Groundrheostat volume
knob positionOFF (Rheostat knob)
turned fully clockNo voltageknob ositionturned fully clock-
wise)No voltage
GroundA8±GroundConstantContinuity
ContinuityA10±GroundConstantContinuityContinuityA22±GroundConstantContinuity
A23±GroundConstantContinuity
*1 Jack up the vehicle.*2 Shift lever position is ºPº range.
If circuit is not as specified, refer to BE±100 wiring diagrams
and inspect the circuits connected to other parts.
BE±108
±
BODY ELECTRICAL SYSTEM Combination Meter
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Page 908 of 4087

(Odometer and Twin Trip Switch)
REMOVAL AND INSTALLATION OF
ODOMETER AND TWIN TRIP SWITCH
(See page BE±103)
INSPECTION OF ODOMETER AND TWIN
TRIP SWITCH
INSPECT ODOMETER AND TWIN TRIP SWITCH
(Continuity)
Inspect continuity between terminals.
If continuity is not as specified, replace the odometer and twin
trip switch.
(Speedometer)
INSPECTION OF SPEEDOMETER
INSPECT SPEEDOMETER (ON±VEHICLE)Using a speedometer tester, inspect the speedometer for al-
lowable indication error and check the operation of the odom-
eter.
HINT: Tire wear and tire over or under inflation will increase
the indication error.
If error is excessive, replace the speedometer.
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BODY ELECTRICAL SYSTEM Combination MeterBE±109
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Page 909 of 4087

(Speed Sensor)
REMOVAL AND INSTALLATION OF
SPEED SENSOR
1. REMOVE SPEED SENSOR(a) Jack up the vehicle.
(b) Disconnect connector and control rod.
(c) Remove a bolt and sensor.
2. INSTALL SPEED SENSOR For installation, follow the removal procedure in reverse.
INSPECTION OF SPEED SENSOR
INSPECT SPEED SENSOR(Operation)
(a) Connect the positive (+) lead from battery to terminal 1and negative (±) lead to terminal 2.
(b) Connect the positive (+) lead from tester to terminal 3 and negative (±) lead to terminal 2.
(c) Revolve shaft.
(d) Check that there is voltage change from approx. 0V to 11V or more between terminal 2 and 3.
HINT: The voltage change should be 4 times per each revolu-
tion of the speed sensor shaft.
If operation is not as specified, replace the sensor.
(Sensor circuit)
Disconnect connector from sensor and inspect the connector
on wire harness side as shown.
Check forTester connectionConditionSpecified value
Voltage1 GroundIgnition switchONBattery positive voltageg1±GroundIgnition switch
positionLOCK or ACCNo voltage
If circuit is not as specified, inspect power source or wire
harness.
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BODY ELECTRICAL SYSTEM Combination MeterBE±110
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Page 910 of 4087

TRAC PUMP AND ACCUMULATOR
TRAC PUMP AND ACCUMULATOR
REMOVAL AND INSTALLATION
BR0F9±03
Remove and install the part, as shown.
MAIN POINTS OF REMOVAL AND
INSTALLATION
1. DRAIN OUT HIGH PRESSURE FLUID
(a) Connect a vinyl tube to the TRAC actuator bleeder plug, then
loosen the bleeder plug.
(b) When the fluid has flowed out, tighten the bleeder plug.
CAUTION: Since the fluid is under high pressure, it could
spray out with great force, so be careful.
2. DISCONNECT AND CONNECT BRAKE LINE Using SST, disconnect and connect the brake line from/to the
accumulator.
SST 09751±36011
Torque: 15 N Vm (155 kgf Vcm, 11 ft Vlbf)
3. BLEED BRAKE SYSTEM AND TRAC SYSTEM
(See page BR±8)
BR±162
±
BRAKE SYSTEM TRACTION CONTROL SYSTEM (TRAC)
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