lock LEXUS SC400 1991 Service Repair Manual

WIRING DIAGRAM
Key Unlock Warning Switch Circuit
CIRCUIT DESCRIPTION
When the key is inserted in the ignition key cylinder the key unlock warning\
switch comes ON, and when the
key is not inserted switch is OFF.
When the key unlock warning switch is ON, the ECU operates the key confi\
nement prevention function.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
NGOK
Proceed to next circuit inspec-
tion shown on matrix chart (See
page
BE±454 ).
Check voltage between terminal KSW of
ECU connector and body ground.
Check and repair harness and connector
between ECU and key unlock warning
switch.
1
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NGOK
INSPECTION PROCEDURE
1Check voltage between terminal KSW of ECU connector and body ground.
C
OK
P1. Remove the rear seat and RH quarter trim panel.
2. Remove the ECU.
3. Key plate is not inserted in the key cylinder.
Measure voltage between terminal KSW of ECU con-
nector and body ground, when key plate is not inserted
in the key cylinder.
Voltage: 10 ± 14 V
Proceed to next circuit inspection shown on matrix chart
(See page BE±454).
Check and repair harness and connector between ECU and key unlock warnin\
g switch.
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BODY ELECTRICAL SYSTEM Wireless Door Lock Control SystemBE±469
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WIRING DIAGRAM
Door Open Detection Switch Circuit
CIRCUIT DESCRIPTION
The door open detection switch comes ON when the door is opened and goes OFF when the door is closed.
Furthermore the door open detection switch circuit has terminal +B connected inside \
the theft deterrent and door
lock ECU, battery positive voltage is applied to terminal DSWD of the wirele\
ss door lock ECU when all doors
are closed, i.e., when the door open detection switch of all doors are O\
FF.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
NG OK
Check open door warning light
circuit (See page
BE±118).
Check operation of open door warning
light
Check voltage between terminal DSWD
of ECU connector and body ground. Proceed to next circuit inspec-
tion show on matrix chart (See
page
BE±454 ).
Check and repair harness and connector
between ECU and door open detection
switch.;
1
2
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OKNG
NGOK
INSPECTION PROCEDURE
1Check operation of open door warning light.
Check that open door warning light comes on when each door is opened, and goes\
off when all doors
are closed.C
Check open door warning light circuit (See page
BE±118 ).
2Check voltage between terminal DSWD of ECU connector and body ground.
C
OK
P1. Remove the rear seat and RH quarter trim panel.
2. Remove the ECU.
3. Wireless door lock main switch on.
Measure voltage between terminal DSWD of ECU con-
nector and body ground, when all doors are closed.
Voltage: 10 ± 14 V
Proceed to next circuit inspection shown on matrix chart
(See page BE±454).
Check and repair harness and connector between ECU and door open detecti\
on switch.
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BODY ELECTRICAL SYSTEM Wireless Door Lock Control SystemBE±471
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±MEMO± BE±472
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GENERAL INFORMATION
Wiring Color Code
Wire colors are indicated by an alphabetical code.
B = Black L = Blue R = Red
BR = Brown LG = Light Green V = Violet
G = Green O = Orange W = White
GR = Gray P = Pink Y = Yellow
The first letter indicates the basic wire color and the second
letter indicates the color of the stripe.
Connector
1. PIN NUMBERS OF FEMALE CONNECTORNumbered in order from upper left to lower right.
2. PIN NUMBERS OF MALE CONNECTOR
Numbered in order from upper right to lower left.
HINT: When connectors with different of the same number of
terminals are used with the same parts, each connector
name (letter of the alphabet) and pin number is specified.
3. DISTINCTION OF MALE AND FEMALE CONNECTORS Male and female connectors are distinguished by shape of
their internal pins.
(a) All connectors are shown from the open end, and thelock is on top.
(b) To pull apart the connectors, pull on the connector itself, not the wires.
HINT: Check to see what kind of connector you are discon-
necting before pulling apart.
BE±2
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How to Replace Terminal
(with Terminal Retainer Type)HINT: To remove the terminal for this type of connector,
please construct and use the special tool or like object shown
on the left.
1. DISCONNECT CONNECTOR Disconnect the connector according to the instructions on
BE±2 .
2. DISCONNECT TERMINAL FROM CONNECTOR (a) Using the special tool, raise the retainer up to thetemporary lock position.
HINT: The needle insertion position varies according to the
connector 's shape (number of terminals, etc.), so check the
position before inserting it.
(b) Using the special tool, release the locking lug and pull the terminal out from rear.
3. INSTALL TERMINAL TO CONNECTOR (a) Insert the terminal.
HINT:
1. Make sure the terminal is positioned correctly.
2. Insert the terminal until the locking lug locks firmly.
3. Insert the terminal with retainer in the temporary lockposition.
(b) Push the retainer in to the full lock position.
4. CONNECT CONNECTOR
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BODY ELECTRICAL SYSTEM General InformationBE±3
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Replacement of Fuse
HINT: If replacing the fuse, be sure to replace it with a fuse
with an equal amperage rating.
NOTICE:
1. Turn off all electrical components and the ignition switchbefore replacing a fuse. Do not exceed the fuse amperage
rating.
2. Always use a fuse puller for removing and inserting a fuse. Remove and insert straight in and out without
twisting. Twisting could force open the terminals too
much, resulting in a bad connection.
If a fuse continues to blow, a short circuit is indicated. The
system must be checked by a qualified technician.
HINT: The puller is located at Relay Block No. 2.
How to Inspect for System Inspection
This inspection precedure is a simple troubleshooting which
should be carried out on the vehicle during system operation
and is based on the assumption of system component
trouble (except for the wires and connectors, etc.).
Always inspect the trouble taking the following items into con-
sideration.
wGround point fault
w Open or short circuit of the wire harness
w Connector or terminal connection fault
w Fuse or fusible link fault
NOTICE:
1. This is an on±vehicle inspection during system
operation. Therefore, inspect the trouble with due regard
for safety.
2. If connecting the battery directly, be careful not to short circuit, and select the applicable voltage.
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PRECAUTIONS
Take care to observe the following precautions when performing inspection\
s or removal and replacement
of body electrical related parts.
1. SRS AIR±BAG SYSTEM

Work must be started approx. 20 seconds after the ignition is set to the Loc\
k position and the negative
(±) terminal cable is disconnected from the battery. (See page AB±2)

When disconnecting any of the connectors in the SRS AIR±BAG system, be su\
re to Lock the ignition
switch and disconnect the battery negative (±) terminal first. Since the connectors are twin \
lock type
connectors, disconnect the connectors only after releasing the first stage lock.

When connecting SRS AIR±BAG system connectors, be sure to lock them secur\
ely. (If the connectors
are not locked securely, the system may not operate when needed.)

Always store the steering wheel pad with the pad surface facing upward. (Stor\
ing the pad with its
metallic surface up may lead to a serious accident if the air bag inflates for s\
ome reason.)

When installing the spiral cable, be sure the vehicle is in the straight ahe\
ad condition and confirm that
the spiral cable is in the neutral position when it is installed. (See pag\
e BE±40)

INFORMATION LABELS (NOTICE) are attached to the periphery of the air bag componen\
ts. Follow
the NOTICE.
2. MICRO COMPUTER PRESET DRIVING POSITION SYSTEM
Power Seat Control System
Power Mirror Control System
Power Tilt and Telescopic Steering System

If the battery negative (±) terminal is disconnected, the preset driv\
ing positions stored in memory are
erased, so be sure to note the positions and reset them after the battery termi\
nal is reconnected.
3. AUDIO SYSTEM

If the battery negative (±) terminal is disconnected, the preset AM, F\
M 1 and FM 2 stations stored in
memory are erased, so be sure to note the stations and reset them after the battery terminal is
reconnected.

If the battery negative (±) terminal is disconnected, the ºANTI±\
THEFT SYSTEMº will operate when
the terminal is reconnected, but the radio, tape player and CD player will \
not operate. Be sure to input
the correct ID number so that the radio, tape player and CD player can be o\
perated again.
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BODY ELECTRICAL SYSTEM PrecautionsBE±7
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Replacement of Relays
REPLACEMENT OF RELAY IN RELAY
BLOCK NO. 1, NO. 4 and NO. 5
1. REMOVE FOLLOWING PARTS:(See page BO±112)
(a) No. 1 under cover.
(b) Door scuff plate.
(c) Floor carpet.
2. REMOVAL AND INSTALLATION OF RELAY
(a) Remove the junction block No. 1 set bolts.
(b) Disconnect connectors.
(c) Separate the relay block No. 4 and No. 5 from the junction block No. 1.
(d) For installation follow the removal procedure in reverse.
Replacement of Relay Block No. 2
(A)
REPLACEMENT OF RELAY BLOCK NO. 2
(A) IN RELAY BLOCK NO. 2
1. REMOVE RELAY BLOCK NO. 2 (A)
(a) Remove 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.
(b) Remove the relay block No. 2 cover.
(c) Pry loose two locking lugs and remove the nut.
2. INSTALL RELAY BLOCK NO. 2 (A) For installation follow removal procedure in reverse.
BE±16
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