ignition switch LEXUS SC400 1991 Service Repair Manual

NGOK
OKNG
INSPECTION PROCEDURE
1Check voltage between terminal STJ of engine & ECT ECU connector and body gro\
und.
C
OK
Hint
PConnect to the Check Harness A.
(See page TR±30)
Disconnect start injector time switch connector.
Disconnect engine & ECT ECU connector.
Measure voltage between terminal STJ of engine &
ECT ECU connector and body ground when ignition
switch is turned to STA.
10 ± 14 V
Go to step 3.
2Check resistance of cold start injector.
C
OK
Hint
PRemove cold start injector (See page FI±27).
Measure resistance between terminals of cold start in-
jector.
Resistance: 2 ± 4
at 20
C (68
F)
Replace cold start injector.
Check and repair harness and connector between
engine & ECT ECU and cold start injector, cold
start injector and battery.
TR±138±
ENGINE TROUBLESHOOTING Circuit Inspection
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NGOK
OKNG
2Check voltage between terminal FPU of engine & ECT ECU connector and body gro\
und.
C
OK
Hint
P(2) Connect the Check Harness A.(See page TR±30)
(2) Turn ignition switch on.
Measure voltage between terminal FPU of engine &
ECT ECU connector and body ground.
Voltage: 10 ± 14 V
Proceed to next circuit inspection shown on matrix chart
(See page TR±35).
3
Check for open and short in harness and connector between engine & ECT ECU an\
d VSV, VSV
and EFI main relay (See page IN±27).
Repair or replace harness or connector
Check and replace engine & ECT ECU.
TR±144±
ENGINE TROUBLESHOOTING Circuit Inspection
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NGOK
OKNG
OKNG
INSPECTION PROCEDURE
1Check voltage between terminals TE1, TE2 and E1 of check connector, TDCL.
C
OK
PTurn ignition switch on.
Measure voltage between terminals TE1, TE2 and E1
of check connector, TDCL.
Voltage: 10 ± 14 V
Check and replace engine & ECT ECT.
2Check continuity between terminal E1 of check connector, TDCL and body ground.
Repair or replace harness or connector.
3
Check for open and short in harness and connector between engine & ECT ECU and che\
ck con-
nector, TDCL (See page IN±27).
Repair or replace harness or connector.
Check and replace engine & ECT ECU.
±
ENGINE TROUBLESHOOTING Circuit InspectionTR±147
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DEFOGGER SYSTEM
Description
The component parts of this system and their functions are described in the\
following table.
 Parts Name\
 \
Function
 Defogger\
 \
When over current flows in the defogger circuit, the Defogger fuse break\
s the circuit to pro-
tect it against damage.
 


Defogger Relay\
 
\

\

This relay is supplied with current from terminal IG1 of ignition switch\
(Ignition switch
ON) and switches large current from the defogger.
 


A/C Control Panel
Assembly

Defogger Switch\
 
\

\

The defogger switch is built into the A/C Control Panel Assembly. This switch is
supplied with current from the relay and fuse HTR. Grounds current from \
the defogger
relay, turning the defogger relay ON.
 




Defogger

Rear Window
 Outer Mirror\
 
\


\

\

These defoggers generate heat when current is supplied from the defogger\
relay.
Parts Location
±
BODY ELECTRICAL SYSTEM Lighting SystemBE±51
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(c) Turn the defogger switch ON and check that the test bulb andindicator light turn ON, then turn OFF after about 15 minutes.
If operation is not as specified, replace the air conditioner control
panel assembly.
(Defogger Relay)
INSPECTION OF DEFOGGER RELAY
INSPECT RELAY CONTINUITY AND OPERATION
If continuity is not as specified, replace the relay.
(Defogger Wires)
INSPECTION AND REPAIR OF
DEFOGGER WIRES
1. INSPECT DEFOGGER WIRESNOTICE:
w When cleaning the glass, use a soft, dry cloth, and wipe
the glass in the direction of the wire. Take care not to
damage the wires.
w Do not use detergents or glass cleaners with abrasive
ingredients.
w When measuring voltage, wind a piece of tin foil around
the top of the negative probe and press the foil against
the wire with your finger as shown.
(a) Turn the ignition switch ON.
(b) Turn the defogger switch ON.
(c) Inspect the voltage at the center of each heat wire as
shown.
 Voltage Criteria
Approx. 5 VOkay (No break in wire) Approx. 10 V or 0 V Broken wire
HINT: If there is approximately 10 volts, the wire is broken be-
tween the center of the wire and the positive (+) end. If there
is no voltage, the wire is broken between the center of the
wire and ground.
±
BODY ELECTRICAL SYSTEM Defogger SystemBE±53
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SYSTEM CIRCUIT
OPERATION
When the ignition switch is turned ON, current from the battery flows from t\
erminal L of the alternator through
the IC regulator to terminal E, causing the discharge warning light to ligh\
t up. Then when the engine is started, the voltage output increases as the alt\
ernator rpm increases. When the
voltage output becomes greater than the battery voltage, current for recharging\
flows from terminal B. Simulta-
neously, volt age at terminal L increases and the potential difference between battery and terminal L disappears,
causing the discharge warning light to go off. When the voltage output exceeds the regulator adjustment volt-
age, the transistor inside the IC regulator regulates the voltage so tha\
t the voltage from the alternator remains
constant.
±
CHARGING SYSTEM System Circuit, OperationCH±3
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(b) Check the belt tensioner operation.w Check that the belt tensioner moves downward
when the drive belt is pressed down at the points
indicated in the illustration with approx. 98 N ( 10
kgf, 22.0 lbf) of force.
w Check the alignment of the belt tensioner pulley to
make sure the drive belt has not slipped off the
pulley.
If necessary, replace the belt tensioner.
w Check that the arrow mark on the belt tensioner falls
within area A of the scale.
If it is outside area A, replace the drive belt.
HINT:
w When a new belt is installed, it should lie within area B.
If not, the drive belt is not correct.
w After installing a belt, check that it fits properly in the
ribbed grooves.
w Check by hand to confirm that the belt has not slipped
out of the groove on the bottom of the pulley.
4. REMOVE ENGINE UNDER COVER
5. VISUALLY CHECK ALTERNATOR WIRING AND LISTEN FOR ABNORMAL NOISES
(a) Check that the wiring is in good condition.
(b) C h e c k t h a t t h e r e i s n o a bnormal noise from the
alternator while the engine is running.
6. INSPECT CHARGE WARNING LIGHT CIRCUIT (a) Warm up the engine and then turn it off.
(b) Turn off all accessories.
(c) Turn the ignition switch ON. Check that the charge
warning light is lit.
(d) Start the engine. Check that the light goes off.
If the light does not go off as specified, troubleshoot the
charge light circuit.
CH±6
±
CHARGING SYSTEM On±Vehicle Inspection
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ALTERNATOR
COMPONENTS FOR REMOVAL AND
INSTALLATION
REMOVAL OF ALTERNATOR
1. DISCONNECT CABLE FROM NEGATIVE TERMINAL OFBATTERY
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.
2. REMOVE ENGINE UNDER COVER
3. REMOVE DRIVE BELT
Loosen the belt tension by turning the drive belt tensioner
counterclockwise, and remove the drive belt.
HINT: The pulley bolt for the belt tensioner has a left±hand
thread.
±
CHARGING SYSTEM AlternatorCH±9
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REMOVAL OF RADIATOR
(See Components on page CO±15)
1. REMOVE BATTERY CAUTION: Work must be started after approx. 20 seconds or
longer from the time the ignition switch is turned to the
ºLOCKº position and the negative (±) terminal cable is dis-
connected from the battery.
2. REMOVE ENGINE UNDER COVERS
3. DRAIN ENGINE COOLANT (See page CO±6)
4. REMOVE RADIATOR RESERVOIR TANK (a) Disconnect the coolant level sensor connector.
(b) Disconnect the following hoses:(1) Reservoir hose from water inlet housing
(2) Reservoir hose from radiator
(c) Remove the two bolts and reservoir tank bracket.
(d) Disconnect the reservoir tank from the reservoir tank bracket, and remove the reservoir tank.
5. DISCONNECT HOSES Disconnect the following hoses:(1) Upper radiator hose from radiator
(2) Lower radiator hose from radiator
(3) Two oil cooler hoses (for A/T) from radiator. Plug hose end.
CO±16
±
COOLIING SYSTEM Radiator
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REMOVAL OF HYDRAULIC PUMP
(See Components on page CO±26)
1. REMOVE 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.
2. REMOVE ENGINE UNDER COVER
3. DRAIN ENGINE COOLANT (See page CO±6)
4. REMOVE DRIVE BELT Loosen the drive belt tension by turning the drive belt tension-
er counterclockwise, and remove the drive belt.
HINT: The pulley bolt for the belt tensioner has a left±hand
thread.
5. DISCONNECT A/C COMPRESSOR (a) Disconnect the A/C compressor connector.
(b) Remove the nut, and disconnect the ground cable.
(c) Remove the bolt and A/C compressor stay.
(d) R e m o v e t h e t w o b o l t s , a n d d i s c onnect the A/C
compressor from the engine.
6. REMOVE LH IGNITION COIL (a) Disconnect the following connectors and cord:(1) Ignition coil connector
(2) Noise filter connector
(3) High±tension cord
±
COOLIING SYSTEM Electronically Controlled Hydraulic
Cooling Fan (Hydraulic Pump)CO±27
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