LEXUS SC400 1991 Service Repair Manual

When disposing of front passenger
airbag assembly only
When disposing of the front passenger airbag assembly
only, never use the customer's vehicle to deploy the air-
bag.
Remove the front passenger airbag assembly from the ve-
hicle and be sure to follow the procedure given below when
deploying the airbag.
HINT: Have a battery ready as the power source to deploy the
airbag.
1. REMOVE FRONT PASSENGER AIRBAG ASSEMBLY CAUTION:
w When removing the front passenger airbag assembly,
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 Store the front passenger airbag assembly with the
airbag door facing up.
2. FIX FRONT PASSENGER AIRBAG ASSEMBLY TO TIRE
Using a service±purpose wire harness for vehicle, tie down
the front passenger airbag assembly to the tire.
Wire harness: Stripped wire harness section
1.25 mm
2 or more (0.0019 in2 or more).
HINT: To calculate the square of the stripped wire harness
section±
Square = 3.14 x (Diameter)2 divided by 4
±
SUPPLEMENTAL RESTRAINT SYSTEM FRONT PASSENGER AIRBAG ASSEMBLYRS±37
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CAUTION: If a wire harness which is too thin or some oth-
er thing is used to tie down the front passenger airbag as-
sembly, it may be snapped by the shock when the airbag
is deployed, this is highly dangerous.
Always use a wire harness for vehicle use which is at
least 1.25 mm
2 (0.0019 in)2.
(1) Wrap the wire harness around the tire, passing the wire
harness at least 3 times through the installation hole on
the left and right sides of the front passenger airbag as-
sembly.
(2) Position the front passenger airbag assembly inside the tire with the airbag door facing inside.
Tie the wire harness to the tire.
Tire size: Must exceed the following dimensions
Width 185 mm (7.28 in.)
Inner diam 360 mm (14.17 in.)
CAUTION:
wMake sure the wire harness is tight. It is very dangerous
if a loose wire harness results in the front passenger
airbag assembly coming free due to the shock of the
airbag deploying.
w Always tie down the front passenger airbag assembly
with the airbag door facing inside.
NOTICE: The tire will be marked by the airbag deploy-
ment, so use a redundant tire.
3. CONFIRM FUNCTIONING OF SST (See page RS±27)
SST 09082±00700
RS±38
±
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4. PLACE TIRES
(a) Place at least 2 tires under the tire to which the front
passenger airbag assembly is tied.
(b) Place at least 2 tires over the tire to which the front passenger
airbag assembly is tied. The top tire should have the wheel
installed.
(c) Tie the tires together by 2 wire harnesses. CAUTION: Make sure that the wire harnesses are tight. It
is very dangerous if looseness in the tires coming free
through the shock of the airbag deploying.
HINT: Place the SST connect and wire harness inside tires.
Provide at least 1 m (3 ft) of slack for the wire harness.
5. INSTALL SST Connect the SST connector to the front passenger airbag as-
sembly connector.
SST 09082±00700
NOTICE: To avoid damaging the SST connector and wire
harness, do not lock the secondary lock of the twin lock.
6. AIRBAG DEPLOYMENT
(a) Connect the SST red clip to the battery positive (+) terminal and the black clip to the battery negative (±) terminal.
(b) Confirm that no±one is within 10 m (33 ft) of the tire the front passenger airbag assembly is tied to.
(c) Press the SST activation switch and deploy the airbag.
±
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7. DISPOSAL OF FRONT PASSENGER AIRBAGASSEMBLY
CAUTION:
w The front passenger airbag assembly 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 front
passenger airbag assembly with deployed airbag.
w Do not apply water, etc., to a front passenger airbag
assembly with deployed airbag.
w Always wash your hand with water after completing the
operation.
(a) Remove the front passenger airbag assembly from the tire.
(b) Place the front passenger airbag assembly in a vinyl bag, tie
the end tightly and dispose of it the same way as other
general parts.
RS±40
±
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FRONT AIRBAG SENSOR
INSPECTION ITEMS
RS015±0C
1. VEHICLES NOT INVOLVED IN A COLLISIONPerform a diagnostic system check.
(See page RS±59)
2. VEHICLES INVOLVED IN A COLLISION
(a) Perform a diagnostic system check. (See page RS±59)
(b) If the front fender of the car or its periphery is damaged, perform visual check for damage to the front airbag sensor,
which includes the following items even if the airbag was not
deployed:
wBracket deformation.
w Peeling of paint from the bracket.
w Cracks, dents or chips in the case.
w Cracks and dents in, or chipping and scratches of the
connector.
w Peeling off of the label or damage to the series number.
Also refer to the body dimension drawings in the BODY sec-
tion and check the dimensions and mounting surface angle
of the body area where the front airbag sensors are mounted.
(The SRS may malfunction, or may not work, if the mounting
angle or dimensions of the sensor mount are not correct.)
REPLACEMENT REQUIREMENTS
RS016±06
In the following cases, replace the front airbag sensor.
NOTICE: for replacement of the front airbag sensor, see
page RS±42 , ªFRONT AIRBAG SENSOR REMOVAL AND
INSTALLATIONº and be sure to follow the correct proce-
dure.
w If the SRS has been deployed in a collision.
(Replace both the left and right airbag sensors.)
w If the front airbag sensor has been found to be faulty in
troubleshooting.
w If the front airbag sensor has been found to be faulty
during the check in item 2±(b).
w If the front airbag sensor has been dropped.
±
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COMPONENTS
RS045±01
FRONT AIRBAG SENSOR
REMOVAL AND INSTALLATION
RS046±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.
w Never reuse the sensor involved in a collision when the
SRS has deployed.
w Never repair a sensor in order to reuse it.
RS±42±
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1. DISCONNECT NEGATIVE (±) TERMINAL CABLE FROMBATTERY
CAUTION: Work must be started after 90 seconds from
the time the ignition switch is turned to the ªLOCKº posi-
tion and the negative (±) terminal cable is disconnected
from the battery.
(See page RS±2)
2. REMOVE ENGINE UNDER COVER
(See page BO±12)
3. REMOVE FRONT AIRBAG SENSOR
(a) Disconnect the connector.
(b) Remove the bolt, the nut and the sensor.
4. INSTALL FRONT AIRBAG SENSOR
(a) Install the sensor with the arrow on the sensor facing toward the front of the vehicle.
Torque: 25 N Vm (260 kgf Vcm, 19 ft Vlbf)
NOTICE:
w Make sure the sensor is installed to the specified torque.
w If the sensor has been dropped, or there are cracks, dents
or other defects in the case, brackets or c onnector,
replace the sensor is removed, always replace the set bolt
and the nut with new one.
w The sensor set bolt and the nut have been anti±rust
treated. When the sensor is removed, always replace the
set bolt and the nut with new ones.
w After installation, shake the sensor to check that there is
no looseness.
w The front sensor is equipped with an electrical
connection check mechanism. 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.
w Check that the dimensions of the body where the front
airbag sensor is installed match those in the body
dimension drawings in the BODY section.
(The SRS may malfunction, or may not work, if the
dimensions of the sensor mount is not correct.)
5. INSTALL ENGINE UNDER COVER
6. CONNECT NEGATIVE (±) TERMINAL CABLE TO BATTERY
±
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CENTER AIRBAG SENSOR
ASSEMBLY
INSPECTION ITEMS
RS047±01
1. VEHICLES NOT INVOLVED IN A COLLISIONPerform a diagnostic system check.
(See page RS±59)
2. VEHICLES INVOLVED IN A COLLISION
IF THE SRS IS NOT DEPLOYED
Perform a diagnostic system check.
(See page RS±59)
IF THE SRS IS DEPLOYED
Replace the center airbag sensor assembly.
REPLACEMENT REQUIREMENTS
RS019±06
In the following cases, replace the center airbag sensor as-
sembly.
NOTICE: For replacement of the center airbag sensor as-
sembly, see page RS±46 ªCENTER AIRBAG SENSOR
ASSEMBLY REMOVAL AND INSTALLATIONº and be sure
to follow the correct procedure.
w If the SRS has been deployed in a collision.
w If the center airbag sensor assembly has been found to
be faulty in troubleshooting.
w If the center airbag sensor assembly has been dropped.
RS±44
±
SUPPLEMENTAL RESTRAINT SYSTEM CENTER AIRBAG SENSOR ASSEMBLY
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COMPONENTS
RS048±01
±
SUPPLEMENTAL RESTRAINT SYSTEM CENTER AIRBAG SENSOR ASSEMBLYRS±45
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CENTER AIRBAG SENSOR ASSEMBLY
REMOVAL AND INSTALLATION
RS049±01
NOTICE:
wDo not open the cover or the case of the ECU and various
computers unless absolutely necessary. (If the IC
terminals are touched, the IC may be destroyed by static
electricity.)
w Never use SRS parts from another vehicle. When
replacing parts, replace with new parts.
w Never reuse the center airbag sensor assembly involved
in a collision when the airbag has deployed.
w Never repair a sensor in order to reuse it.
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. REMOVE AND INSTALL CENTER AIRBAG SENSOR ASSEMBLY
(a) Using a torx wrench, loosen and tighten the 3 screws.
Torx wrench: T40 (Part No. 09042±00020 or locally manufac-
tured tool)
(b) Disconnect and connect the connector. NOTICE: Removal and installation of the connector is
done with the sensor assembly installed.
(c) Using a torx wrench, tighten the 3 screws. Torx wrench: T40 (Part No. 09042±00020 or locally manufac-
tured tool)
Torque: 15 N Vm (150 kgf Vcm, 11 ft Vlbf)
NOTICE:
w Make sure the sensor assembly is installed to the
specified torque.
w If the sensor assembly has been dropped, or there are
cracks, dents or other defects in the case, bracket or
connector, replace the sensor assembly with a new one.
w When installing the sensor assembly, take care that the
airbag wiring does not interfere with other parts and is
not pinched between other parts.
w After installation, shake the sensor assembly to check
that there is no looseness.
RS±46±
SUPPLEMENTAL RESTRAINT SYSTEM CENTER AIRBAG SENSOR ASSEMBLY
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