lock LEXUS SC400 1991 Service Repair Manual

FRONT AIRBAG SENSOR
RS00N±07
1. Never reuse the front airbag sensor involved in a collision when the airbag h\
as deployed. (Replace boththe left and right airbag sensors.)
2. Install the front airbag sensor with the arrow on the sensor facing towa\
rd the front of the vehicle.
3. The front airbag sensor set bolts have been anti±rust treated. When the \
sensor is removed, always replace
the set bolts with new ones.
4. The front airbag sensors is equipped with an electrical connection check me\
chanism. Be sure to lock this mechanism securely when connecting the connector. If the connector is not securely locked, a malfunction
code will be detected by the diagnosis system (See page RS±12).
CENTER AIRBAG SENSOR ASSEMBLY
RSOOR±0A
1. Never reuse the center airbag sensor assembly involved in a collision when the airbag has
deployed.
2. Work must be started after 90 seconds from the time the ignition switch is t\
urned to LOCK position and the negative (±) terminal cable is disconnected from the batter\
y even just loosing the set bolts
of center airbag sensor assembly.
WIRE HARNESS AND CONNECTOR
RSO41±01
The SRS wire harness is integrated with the cowl wire harness assembly. The wires for the SRS wire har-
ness are encased in a yellow corrugated tube. All the connectors for the sys\
tem are also a standard yellow
color. If the SRS wire harness becomes disconnected or the connector becomes broken du\
e to an accident
etc., repair or replace it as shown on page RS±48.
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SUPPLEMENTAL RESTRAINT SYSTEM GENERAL DESCRIPTIONRS±5
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6. CENTER AIRBAG SENSOR ASSEMBLYThe center airbag sensor assembly is mounted on the floor
inside the center cluster. The center airbag sensor assembly
consists of a center airbag sensor, safing sensor, diagnosis
circuit and ignition control, drive circuit, etc.
It receives signals from the airbag sensors, judges whether
the SRS must be activated or not.
7. SRS CONNECTORS
 No. Item Application
 (1) Terminal Twin±Lock Mechanism Connectors
,  ,  ,  ,  ,  , 
 (2) Airbag Activation Prevention Mechanism Connectors
,  ,  , 
 (3) Electrical Connection Check Mechanism Connectors
,  ,  (4) Connector Twin±Lock Mechanism Connectors  ,  , 
All connectors in the supplemental restraint system are col-
ored yellow to distinguish them from other connectors. Con-
nectors having special functions and specifically designed
for SRS are used in the locations shown below to ensure high
reliability. These connectors use durable gold±plated termi-
nals.
RS±10
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SUPPLEMENTAL RESTRAINT SYSTEM OPERATION
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(1) Terminal Twin±Lock MechanismEach connector has a two±piece construction consisting of
a housing and a spacer. This design secures the locking of
the terminal by two locking devices (the spacer and the lance)
to prevent terminals from coming out.
(2) Airbag Activation Prevention Mechanism Each connector contains a short spring plate. When the con-
nector is disconnected, the short spring plate automatically
connects the power source and grounding terminals of the
squib.
HINT: The illustration shows connectors ,  and  . Con-
nector

has short spring plates on the female terminal side.
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SUPPLEMENTAL RESTRAINT SYSTEM OPERATIONRS±11
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(3) Electrical Connection Check MechanismThis mechanism is designed to electrically check if connec-
tors are connected correctly and completely. The electrical
connection check mechanism is designed so that the con-
nection detection pin connects with the diagnosis terminals
when the connector housing lock is in the locked condition.
HINT: The illustration shows connectors  and  Connector,
also has the same operating principle.
RS±12
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SUPPLEMENTAL RESTRAINT SYSTEM OPERATION
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(4) Connector Twin±Lock MechanismWith this mechanism connectors (male and female connec-
tors) are locked by 2 locking devices to increase connection
reliability. If the primary lock is incomplete, ribs interfere and
prevent the secondary lock.
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SUPPLEMENTAL RESTRAINT SYSTEM OPERATIONRS±13
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COMPONENTS
RS04D±01
STEERING WHEEL PAD AND SPIRAL
CABLE REMOVAL AND INSTALLATION
RS04D±01
NOTICE:
wIf the wiring connector of the supplemental restraint
system is disconnected with the ignition switch at ON or
ACC, diagnostic trouble codes will be recorded.
w Never use SRS parts from another vehicle. When
replacing parts, replace with new parts.
1. DISCONNECT NEGATIVE (±) TERMINAL CABLE FROM
BATTERY
CAUTION: Work must be started after 90 seconds from
the time the ignition switch is turned to the LOCK posi-
tion and the negative (±) terminal cable is disconnected
from the battery (See page RS±2).
RS±18
±
SUPPLEMENTAL RESTRAINT SYSTEM STEERING WHEEL PAD AND SPIRAL CABLE
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2. REMOVE STEERING WHEEL PAD
(a) Place the front wheels facing straight ahead.
(b) Using a torx wrench, loosen the 4 screws. Torx wrench: T30(Part No. 09042±00010 or locally manufactured tool)
(d) Loosen the torx screws until the groove along the screw circumference catches on the screw case.
(e) P u l l t h e w heel pad out from the steering wheel and
disconnect the SRS connector.
NOTICE: When removing the wheel pad, take care not to
pull the airbag wire harness.
CAUTION:
w When storing the wheel pad, keep the upper surface of
the pad facing upward (See pages RS±3).
w Never disassemble the wheel pad.
3. REMOVE STEERING WHEEL
(a) Disconnect the connector.
(b) Remove the set nut.
(c) Place matchmarks on the steering wheel and main shaft.
(d) Using SST, remove the steering wheel.
SST 09213±31021
4. REMOVE AND INSTALL SPIRAL CABLE FROM/TO COMBINATION SWITCH
(See page BE±51)
NOTICE: Do not disassemble the spiral cable or apply oil
to it.
5. CENTER SPIRAL CABLE
(a) Check that the front wheels are facing straight ahead.
(b) Turn the spiral cable c ounterclockwise by hand until it
becomes harder to turn the cable.
(c) Then rotate the spiral cable clockwise about 3 turns to align the red mark.
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SUPPLEMENTAL RESTRAINT SYSTEM STEERING WHEEL PAD AND SPIRAL CABLERS±19
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When scrapping vehicle
HINT: Have a battery ready as the power source to deploy the
airbag.
1. DISCONNECT NEGATIVE (±) TERMINAL CABLE FROM BATTERY
CAUTION: Work must be started after 90 seconds from
the time the ignition switch is turned to the LOCK posi-
tion and the negative (±) terminal cable is disconnected
from the battery (See page RS±2).
2. CONFIRM FUNCTIONING OF SST (See page RS±27)
SST 09082±00700
3. INSTALL SST CAUTION: Check that there is no looseness in the steer-
ing wheel and steering wheel pad.
(a) Remove the No.1 under cover.
(b) Disconnect the airbag connector of the spiral cable.
(c) Connect the SST connector to the airbag connector of the spiral cable.
SST 09082±00700
(d) Move the SST to at least 10 m (33 ft) from the front of the vehicle.
(e) Close all the doors and windows of the vehicle. NOTICE: Take care not to damage the SST wire harness.
(f) Connect the SST red clip to the battery positive (+) terminal and the black clip to the battery negative (±) terminal.
RS±22±
SUPPLEMENTAL RESTRAINT SYSTEM STEERING WHEEL PAD AND SPIRAL CABLE
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4. DEPLOY AIRBAG
(a) Confirm that no±one is inside the vehicle or within 10 m (33ft) of the vehicle.
(b) Press the SST activation switch and deploy the airbag. HINT: The airbag deploys simultaneously as the LED of the
SST activation switch lights up.
5. DISPOSAL OF STEERING WHEEL PAD (WITH AIRBAG)
CAUTION:
w The steering wheel pad is very hot when the airbag is
deployed, so leave it alone for at least 30 minutes after
deployment.
w Use gloves and safety glasses when handling a steering
wheel pad with deployed airbag.
w Do not apply water, etc. to a steering wheel pad with
deployed airbag.
w Always wash your hands with water after completing the
operation.
(a) When scrapping a vehicle, deploy the airbag and scrap the
vehicle with the steering wheel pad still installed.
(b) When moving a vehicle for scrapping which has a steering
wheel pad with deployed airbag, use gloves and safety
glasses.
When disposing of the steering wheel
pad only
When disposing of the steering wheel pad (with airbag)
only, never use the customer's vehicle to deploy the air-
bag.
Remove the steering wheel pad from the vehicle and be sure
to follow the procedure given below when deploying the air-
bag.
HINT: Have a battery ready as the power source deploy the
airbag.
1. REMOVE STEERING WHEEL PAD (See page RS±18)
CAUTION:
w When removing the steering wheel pad (with airbag),
work must be started after 90 seconds from the time the
ignition switch is turned to the LOCK position and the
negative (±) terminal cable is disconnected from the
battery.
w When storing the steering wheel pad, keep the upper
surface of the pad facing upward.
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SUPPLEMENTAL RESTRAINT SYSTEM STEERING WHEEL PAD AND SPIRAL CABLERS±23
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(2) Face the upper surface of the steering wheel pad upward.
(3) Separately tie the left and right sides of the steering wheelpad to the disc wheel through the hub nut holes.
(c) Position the steering wheel pad connector so that it hangs downward through a hub hole in the disc wheel.
CAUTION:
w Make sure that the wire harness is tight. It is very
dangerous if looseness in the wire harness results in the
steering wheel pad coming free through the shock of the
airbag deploying.
w Always tie down the steering wheel pad with the pad side
facing upward. It is very dangerous if the steering wheel
pad is tied down with the metal surface facing upward as
the wire harness will be cut by the shock of the airbag
deploying and the steering wheel pad will be thrown into
the air.
HINT: The disc wheel will be marked by airbag deployment,
so use a redundant disc wheel.
4. CONFIRM FUNCTIONING OF SST (See page RS±27)
SST 09082±00070
5. INSTALL SST CAUTION: Place the disc wheel on level ground.
(a) C onnect the SST connector to the steering wheel pad
connector.
SST 09082±00700
NOTICE: To avoid damaging the SST connector and wire
harness, do not lock the secondary lock of the twin lock.
Also provide some slack for the SST wire harness inside
the disc wheel.
(b) Move the SST to at least 10 m (33 ft) away from the steering wheel pad tied down on the disc wheel.
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SUPPLEMENTAL RESTRAINT SYSTEM STEERING WHEEL PAD AND SPIRAL CABLERS±25
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