LEXUS SC400 1991 Service Repair Manual

IF THE AIRBAG IS DEPLOYED
(a) Perform a diagnostic system check. (See page RS±59)
(b) Perform a visual check which includes the following items
with the steering wheel pad (with airbag) removed from he
vehicle.
wCheck for deformation of the horn button contact plate
of the steering wheel.
w Check for damage to the spiral cable connector and wire
harness.
HINT:
w If the horn button contact plate of the steering wheel is
deformed, never repair it. Always replace the steering
wheel assembly with a new one.
w There should be no interference between the steering
wheel pad and the steering wheel, and the clearance
should be uniform all the way around when the new
steering pad is installed on the steering wheel.
REPLACEMENT REQUIREMENTS
RS011±02
In the following cases, replace the steering wheel pad, steer-
ing wheel or spiral cable.
CAUTION: For replacement of the steering wheel pad,
see page RS±18, ªSTEERING WHEEL PAD AND SPIRAL
CABLE REMOVAL AND INSTALLATIONº and be sure to
follow the correct procedure.
w If the airbag has been deployed.
w If the steering wheel pad or spiral cable has been found
to be faulty in troubleshooting.
w If the steering wheel pad, steering wheel or spiral cable
has been found to be faulty during the check in item
1±(b) or 2±(b).
w If the steering wheel pad has been dropped.
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SUPPLEMENTAL RESTRAINT SYSTEM STEERING WHEEL PAD AND SPIRAL CABLERS±17
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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
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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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6. INSTALL STEERING WHEEL
(a) Align matchmarks on the steering wheel and main shaft, andinstall the steering wheel to the main shaft.
(b) Install and torque the set nut.
Torque: 35 N Vm (360 kgf Vcm, 26 ft Vlbf)
(c) Connect the connector.
7. INSTALL STEERING WHEEL PAD
(a) Connect the SRS connector.
(b) Install the wheel pad after confirming that the circumference
groove of the torx screws is caught on the screw case.
(c) Using a torx wrench, tighten the 4 screws.
Torque: 7.4 N Vm (75 kgf Vcm, 65 in. Vlbf)
NOTICE:
w Make sure the wheel pad is installed to the specified
torque.
w If the wheel pad has been dropped, or there are cracks,
dents or other defects in the case or connector, replace
the wheel pad with a new one.
w When installing the wheel pad, take care that the wirings
do not interfere with other parts and are not pinched
between other parts.
8. CHECK STEERING WHEEL CENTER POINT
9. CONNECT NEGATIVE (±) TERMINAL CABLE TO
BATTERY
RS±20
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STEERING WHEEL PAD (WITH AIRBAG)
DISPOSAL
RS04E±01
When scrapping vehicles equipped with a supplemental re-
straint system or disposing of a steering wheel pad (with air-
bag), always first deploy the airbag in accordance with the
procedure described below.
If any abnormality occurs with the airbag deployment, con-
tact the SERVICE DEPT. of TOYOTA MOTOR SALES,
U.S.A., INC..
Never dispose of a steering wheel pad which has an un-
deployed airbag.
When disposing of a steering wheel pad with an airbag
deployed in a collision, follow the same procedure given un-
der ªWhen scrapping vehicle, step 5. DISPOSAL OF STEER-
ING WHEEL PAD (WITH AIRBAG)º (See page RS±23).
PRECAUTIONS FOR AIRBAG DEPLOYMENT
w The airbag produces a sizeable exploding sound when
it deploys, so perform the operation out±of±doors and
where it will not create a nuisance to nearby residents.
w When deploying the airbag, always use the specified
SST; SRS AIRBAG DEPLOYMENT TOOL (SST
09082±00700). Perform the operation in a place away
from electrical noise.
w When deploying an airbag, perform the operation from
at least 10 m (33 ft) away from the steering wheel pad.
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 Always wash your hands with water after completing the
operation.
w Do not apply water, etc. to a steering wheel pad with
deployed airbag.
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SUPPLEMENTAL RESTRAINT SYSTEM STEERING WHEEL PAD AND SPIRAL CABLERS±21
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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±
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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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2. REMOVE STEERING WHEEL PAD CONNECTORRemove the connector on the steering wheel pad rear sur-
face from the inflater cover.
3. FIX STEERING WHEEL PAD TO DISC WHEEL WITH TIRE
(a) Install the 4 bolts with washer in the 4 bolt holes in the steering wheel pad.
Bolt:
L 35.0 mm (1.398 in.) M 6.0 mm (0.236 in.) Pitch 1.0 mm
(0.039 in.)
NOTICE:
wTighten the bolts by hand until the bolts become difficult
to turn.
w Do not tighten the bolts too much.
(b) Using a service±purpose wire harness for vehicle tie down
the steering wheel pad to the disc wheel.
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
CAUTION: If a wire harness which is too thin or some oth-
er thing is used to tie down the steering wheel pad it may
be snapped by the chock 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 in2.).
(1) Using 3 wire harnesses, wrap the wire harnesses at least 2 times each around the bolts installed on the left and
right sides of the steering wheel pad.
CAUTION:
w Tightly wind the wire harness around the bolts so that
there is no slack.
w If there is slackness in the wire harness, the steering
wheel pad may come loose due to the shock when the
airbag is deployed, this is highly dangerous.
RS±24±
SUPPLEMENTAL RESTRAINT SYSTEM STEERING WHEEL PAD AND SPIRAL CABLE
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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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6. COVER STEERING WHEEL PAD WITH CARDBOARDBOX OR TIRES
Covering Method Using Cardboard Box:
Cover the steering wheel pad with the cardboard box and
weigh the cardboard box down in four places with a at least
196 N (20 kgf, 44 lbf).
Size of cardboard box:
Must exceed the following dimensions±
x = 460 mm (18.11 in.) When dimension y of the cardboard box exceeds the
diameter of the disc wheel with tire the steering wheel
pad is tied to±
x = 460 mm (18.11 in.) + width of tire
y = 650 mm (25.59 in.)
NOTICE: If a cardboard box smaller than the size speci-
fied is used, the cardboard box will be broken by the
shock of the airbag deployment.
Covering Method Using Tires:
Place at least 3 tires without disc wheel on top of the disc
wheel with tire to which the steering wheel pad is tied.
Tire size: Must exceed the following dimensions± Width 185 mm (7.28 in.)
Inner diam 360 mm (14.17 in.)
CAUTION: Do not use tires with disc wheels.
NOTICE: The tires by marked by the airbag deployment,
so use redundant tires.
7. 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 disc wheel the steering wheel pad is tied to.
(c) Press the SST activation switch and deploy the airbag. HINT: The airbag deploys simultaneously as the LED of the
SST activation switch lights up.
RS±26±
SUPPLEMENTAL RESTRAINT SYSTEM STEERING WHEEL PAD AND SPIRAL CABLE
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