warning LEXUS SC400 1991 Service Owner's Guide

( Coolant Level Warning Switch)
REMOVAL AND INSTALLATION OF COOLANT
LEVEL WARNING SWITCH
1. REMOVE COOLANT LEVEL WARNING SWITCH(a) Disconnect the connector.
(b) Remove the boot.
(c) Using the notches in the head of switch, turn the switchcounterclockwise and remove it.
NOTICE: Do not remove when engine is hot.
2. INSTALL COOLANT LEVEL WARNING SWITCH For installation, follow the removal procedure in reverse.
INSPECTION OF COOLANT LEVEL WARNING
SWITCH
1. INSPECT COOLANT LEVEL WARNING SWITCH(Continuity)
(a) Remove the radiator cap and open the radiator drainclock.
NOTICE: Do not remove when engine is hot.
(b) Drain the coolant about 1 liter. (1.1 US qts, 0.9 lmp. qts)
(c) Check that there is continuity between terminals (float down).
(d) Close radiator drain cock and fill the cooling system with
coolant.
(e) Check that there is no continuity between terminals (float up).
If continuity is not as specified, replace the switch.
2. INSPECT COOLANT LEVEL WARNING LIGHT (a) Disconnect the connector from the coolant level warning
switch and ground terminal 1 on the wire harness side
connector.
(b) Start the engine, check that the warning light lights up.
If the warning light does not light up, inspect the bulb or wire
harness.
±
BODY ELECTRICAL SYSTEM Combination MeterBE±117
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LIQUID CRYSTAL INNER MIRROR
SYSTEM
Description
The liquid crystal inner mirror replaces the previous mirror, which mechanically switched between the ªDayº and
ªNightº settings, with liquid crystal inside the mirror which changes the bright\
ness of the mirror surface. The com-
ponent parts of this system and their functions are shown in the table below.
Parts NameFunction
Liquid Crystal Inner
MirrorReceives current from the fuse DOME and changes the surface brightness o\
f the mirror
when switch is operated.
Key Unlock Warning
SwitchOpens the circuit so that the mirror can be operated only when the ignit\
ion key is set.
Parts Location
BE±164±
BODY ELECTRICAL SYSTEM Liquid Crystal Inner Mirror System
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(b) Press the mirror switch and check if the mirrors surfacerepeatedly becomes ºbrightº and ºdarkº.
If operation is not as specified, replace the liquid crystal inner
mirror.
(Circuit)
Disconnect the inner mirror connector and inspect the con-
nector on the wire harness side as shown.
Check forTester connectionConditionSpecified value
Voltage2±GroundConstantBattery voltage
Continuity1 GroundIgnition key setContinuityContinuity1±GroundIgnition key removedNo continuity
If circuit is not as specified, refer to BE±165 wiring diagram
and inspect the circuits connected to other parts.
(Key Unlock Warning Switch)
(See page BE±26)
Troubleshooting
You will find the cause of trouble more easily by properly using the table \
shown below. In this table, the numbers
indicate the order of priority of the cruses of trouble. Check each part in the \
order shown. If necessary, replace
the part.
See pageBE±4,21BE±165BE±26 ±±
TroubleParts
name
DOME FuseLiquid Crystal Inner MirrorKey Unlock Warning SwitchWire Harness
Liquid Crystal Inner Mirror does not operate.1234
BE±166±
BODY ELECTRICAL SYSTEM Liquid Crystal Inner Mirror System
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TERMINALS OF ECU
 No. Symbol Terminal Name No. Symbol Terminal Name T8±3 ACT ± Door Lock Motor T8±13 DSWD Door Open Detection Switch 

T8±4
 

ACT +
 

Door Lock Motor
 

T8±14
 

L1
 

Door Key Lock and Unlock Switch
(Lock)
 

T8±5
 

TO
 

Luggage Compartment Door Opener
Motor 

T8±15
 

UL1
 

Door Key Lock and Unlock Switch
(Unlock)
 T8±6 KSW Key Unlock Warning Switch T8±16 E Ground 

T8±7 

LSWP 

Door Unlock Detection Switch 

T8±17 

L2 

Door Lock Control Switch (Lock)
 T8±8 + B2 Actuator Power Source T8±18 UL2 Door Lock Control Switch (Unlock)
 


T8±10 


UL3 


Door Key Lock and Unlock Switch
(Unlock) 


T8±19 


TSW 


Luggage Compartment Door Opener
Switch
 T8±11 LSWD Door Unlock Detection Switch T8±20 + B1 ECU Power Source
 T8±12 DSWP Door Open Detection Switch   
BE±368±
BODY ELECTRICAL SYSTEM Door Lock Control System
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STANDARD VALUE OF ECU TERMINAL
 

Terminals 

Symbols 


Wiring
Color 

Condition 

Standard Value
 T9±3
e T9±4 ACT e ACT+ L±W e L±R Ignition switch OFF 50
or less
 T9±5 e T9±16 T0 e E B e W±B Ignition switch OFF 100
or less
 
T9 6 eT9 16
 
KSW eE
 
Ye WB
 Key unlock warning switch ON.
(Key is inserted into key cylinder). 1
or less
 


T9±6
e T9±16 


KSW
e E 


Y
e W±B 

Key unlock warning switch OFF.
(Key is not inserted into key cylinder). 

1 M

or higher
 

T9±7
e T9±16
 

LSWP
e E
 

P±B
e W±B
 


Door unlock detection switch ON.
(Passenger's) 

1

or less
    Door unlock detection switch OFF. 1 M
higher
 T9±8 e T9±16 +B2 e E L±W e W±B Always 10±14 V
 
T9 10 eT9 16
 
UL3 eE
 
Ge WB
 Door key lock and unlock switch ºunlockº
position. 1
or less
 


T9±10
e T9±16 


UL3
e E 


G
e W±B 

Door key lock and unlock switch OFF or
ºlockº position. 

1 M

or higher
 
T9 11 eT9 16
 
LSWD eE
 
WL eWB
 Door unlock detection switch ON. (driver's) 1
or less
 T9±11 e T9±16 LSWD e E W±L e W±B Door unlock detection switch OFF. (driver's) 1 M
or higher
 

T9 12
eT9 16
 

DSWP
eE
 

RW
eWB
 


Door open detection switch (passenger's)
ON (door opened). 

1

or less
 


T9±12
e T9±16 


DSWP
e E 


R±W
e W±B 


Door open detection switch (passenger's)
OFF (door closed). 


1 M

or higher
 
T9 13 eT9 16
 
DSWD eE
 
RB eWB
 Door open detection switch (driver's)
ON (door opened). 1
or less
 


T9±13
e T9±16 


DSWD
e E 


R±B
e W±B 

Door open detection switch (driver's)
OFF (Door closed). 

1 M

or higher
 

T9 14
eT9 16
 

L1
eE
 

GY
eWB
 


Door key lock and unlock switch ºlockº
position. 

1

or less
 


T9±14
e T9±16 


L1
e E 


G±Y
e W±B 


Door key lock and unlock switch OFF or
ºunlockº position. 


1 M

or higher
 
T9 15 eT9 16
 
UL1 eE
 
GW eWB
 Door key lock and unlock switch ºunlockº
position. 1
or less
 


T9±15
e T9±16 


UL1
e E 


G±W
e W±B 

Door key lock and unlock switch OFF or
ºlockº position. 

1 M

or higher
 


T9±16
e Body
Ground 


E
e Body
Ground 


W±B
e Body
Ground 

Always 

1

or less
    Door lock control switch ªlockº position. 1
or less
 

T9±17 e T9±16 

L2 e E 

R±B e W±B 

Door lock control switch OFF or ªunlockº
position. 

1 M
or higher
    Door lock control switch ªunlockº position 1
or less 

T9±18
e T9±16 

UL2
e E 

G±L
e W±B 

Door lock control switch OFF or ªlockº
position. 

1 M

or higher
±
BODY ELECTRICAL SYSTEM Door Lock Control SystemBE±369
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MATRIX CHART OF PROBLEM SYMPTOMS
Perform troubleshooting of the circuits for the applicable problem symptom in t\
he order given in the chart below.
Proceed to the page located for each circuit.
HINT:
If the instruction ªProceed to next circuit inspection shown on matrix \
chartº is given in the flow chart for each
circuit, proceed to the circuit with the next highest number in the table to con\
tinue the check.

If the trouble still reappears even though there are no abnormalities in a\
ny of the other circuits, then check
or replace the Theft Deterrent and Door Lock ECU as the last step.
See page
BE±376BE±378BE±380BE±382BE±384BE±386BE±388BE±390BE±392IN±32
SymptomSuspect Area
ECU Power Source CircuitActuator Power Source CircuitDoor Lock Motor CircuitLuggage Compartment Door Opener Motor
CircuitDoor Lock Control Switch CircuitDoor key Lock and Unlock Switch CircuitKey Unlock Warning Switch CircuitLuggage Compartment Door Opener Main
Switch and Opener Switch CircuitDoor Open Detection Switch CircuitTheft Deterrent and Door Lock ECU
Whole functions of the door lock control system does notWhole functions of the door lock control system does not
t12435operate.12435
All doors or some doors are not locked and unlocked with theAll doors or some doors are not locked and unlocked with the
Door Lock Control Switch and Key o
perated SwitchDoor Lock Control Switch and Key operated Switch.
(Luggage compartment door opener function normally oper3124(Luggage compartment door opener function normally oper-
t)
3124
ate.)
Doors cannot be locked or unlocked with the door lock con-Doors cannot be locked or unlocked with the door lock con
trol switch. (Doors lock and unlock normally with the key op-1234(yy
erated switch.)
1234
Doors are not locked or unlocked with the key operatedDoors are not locked or unlocked with the key o erated
switch. (Doors lock and unlock normally with the door lock12(y
control switch.)
12
Key confinementprevention function does not operateKey confinement prevention function does not operate.123y
Doors lock and unlock normally with the key o
perated switch123Doors lock and unlock normally with the key operated switch.
Luggage compartment door opener function does not oper-Luggage compartment door opener function does not oper-
t213ate.213
±
BODY ELECTRICAL SYSTEM Door Lock Control SystemBE±371
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OKOK NG NG
Check key unlock warning switch.
Check harness and connectors between ECU and
key unlock warning switch, key unlock warning
switch and body ground (See page
IN±27).
Replace key unlock warning
switch.1
2
Proceed to next circuit inspection shown on
matrix chart (See page BE±371). Repair or replace harness or
connector.
WIRING DIAGRAM
Key Unlock Warning Switch Circuit
CIRCUIT DESCRIPTION
The key unlock warning switch goes on when the ignition key is inserted in the key cylinder and goes
off when the ignition key is removed.
The ECU operates the key confinement prevention function while the key unlo\
ck warning switch is on.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
BE±388±
BODY ELECTRICAL SYSTEM Door Lock Control System
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OKNG
OKNG
INSPECTION PROCEDURE
1Check key unlock warning switch.
C
OK
PDisconnect key unlock warning switch connector.
Check continuity between terminal 9 and 10 of key un-
lock warning switch connector, when the key is inserted
to the key cylinder or removed.
Replace key unlock warning switch.
2Check harness and connectors between ECU and key unlock warning switch, key un\
lock warn-
ing switch and body ground (See page IN±27).
Repair or replace harness or connector.
Proceed to next circuit inspection shown on ma-
trix chart (See page BE±371).
±
BODY ELECTRICAL SYSTEM Door Lock Control SystemBE±389
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Terminals of ECU
WIRING DIAGRAM
No.SymbolTerminal NameNo.SymbolTerminal Name
W8±1+BPower SourceW8±6KSWKey Unlock Warning Switch
W8±2LSWD1Door Unlock Detection Switch LHW8±7EGround
W8±3LSWPDoor Unlock Detection Switch RHW8±8
W8±4UL1Door Key Lock and Unlock SwitchW8±9LSWD2Door Lock Motor LH
W8±5L1Door Key Lock and Unlock SwitchW8±10DSWDDoor Open Detection Switch
BE±452±
BODY ELECTRICAL SYSTEM Wireless Door Lock Control System
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MATRIX CHART OF PROBLEM SYMPTOMS
Perform troubleshooting of the circuits for the applicable problem symptom in t\
he order given in the chart below.
Proceed to the page located for each circuit.
HINT:
w Troubleshooting of the wireless door lock control system is based on the premise that the d\
oor lock
control system is operating normally. Accordingly, before troubleshooting the wireless door lock
control system, first make certain that the door lock control system is \
operating normally.
w If the instruction ºProceed to next circuit inspection shown on matrix \
chartº is given in the flow chart for each
circuit, proceed to the circuit with the next highest number in the table to con\
tinue the check.
w If the trouble still reappears even though there are no abnormalities in a\
ny of the other circuits, then check
and replace the Wireless Door Lock ECU as the last step.
See page
BE±460BE±462BE±464BE±466BE±468BE±470IN±32
SymptomSuspect
Area
ECU Power Source CircuitDoor Unlock Detection Switch CircuitDoor Key Lock and Unlock Swtich Circuit
(Unlock Side)Door Key Lock and Unlock Swtich Circuit
(Lock Side)Key Unlock Warning Switch CircuitDoor Open Detection Swtich CircuitWireless Door Lock ECU
All functions of wireless door lock control system do not
operate.134526
Only door unlock operation is not possible
(Lock operation is possible).213
Only door lock operation is not possible
(Unlock operation is possible).12
Only transmitter misoperation prevention function is not
possible12
Wireless door lock function operates even when each door is
opened.12
Wireless door lock functions incorrectly.
(Although one door is unlocked, when the transmitter switch
is pressed, all doors unlock.)
12
BE±454±
BODY ELECTRICAL SYSTEM Wireless Door Lock Control System
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