1991 LEXUS SC400 lock

1
(1) Turn ignition switch LOCK.
(2) Disconnect negative (±) terminal cable frombattery.
(3) Disconnect center airbag sensor assembly connector.
(4) Connect negative (±) terminal cable to battery.
Does airbag warning light turn off?
Check airbag warning light circuit or terminal
AB circuit of TDCL or check connector.NG
YES
Check operation of airbag warning light.
Replace center airbag sensor assembly.
INSPECTION PROCEDURE
±
SRS AIRBAG TroubleshootingAB±85
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NGOK
Check center airbag sensor assembly.3
(1) Disconnect negative (±) terminal cable from
battery, and wait at least 20 seconds.
(2) Turn ignition switch lock.
(3) Disconnect center airbag sensor assembly
connector.
(4) Using a service wire, connector terminal Tc of center airbag sensor assembly connector to
body ground.
(5) Install the center airbag sensor assembly.
(6) Connect negative (±) terminal cable to battery.
(7) Turn ignition switch ACC or ON.
Check operation of airbag warning light.
Airbag light comes on.
Check harness between center airbag sensor
assembly and TDCL or check connector.
Replace center airbag sensor assembly.
C
P
OK
CautionNever turn ignition switch ACC or ON and
never connect negative (±) terminal to battery
before the center airbag sensor assembly is
installed.
±
SRS AIRBAG TroubleshootingAB±89
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NGOK
Check resistance between terminal Tc of center airbag sensor
assembly and body ground.1
Check resistance between terminal Tc of center
airbag sensor assembly and body ground.
Replace center airbag sensor assembly.
Resistance: 1M

or higher
(1) Turn ignition switch LOCK.
(2) Disconnect center airbag sensor assembly
connector.
Repair or replace harness or connector.
HINT: If the diagnostic code is continuously displayed, perform the followin\
g troubleshooting. AB±90
±
SRS AIRBAG Troubleshooting
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DISPOSAL OF STEERING WHEEL
PAD (WITH AIRBAG)
When scrapping vehicles equipped with an airbag system or dis-
posing of a steering wheel pad (with airbag), always first deploy
the airbag in accordance with the procedure described below.
If any abnormality occurs with the airbag deployment, contact the
SERVICE DEPT. of TOYOTA MOTOR SALES, U.S.A., INC..
Never dispose of a steering wheel pad which has an
undeployed airbag.
When disposing of a steering wheel pad with an airbag deployed
in a collision, follow the same procedure given under ªAIRBAG
DEPLOYMENT PROCEDURE (WHEN SCRAPPING THE VE-
HICLE), part 5, DISPOSAL OF STEERING WHEEL PAD (WITH
AIRBAG)º (See page AB±93).
PRECAUTIONS FOR AIRBAG DEPLOYMENT
1. 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.
2. 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.
3. When deploying an airbag, perform the operation from at least 10 m (33 ft) away from the steering wheel pad.
4. The steering wheel pad is very hot when the airbag is deployed, so leave it alone for at least 30 minutes after
deployment.
5. Use gloves and safety glasses when handling a steering
wheel pad with deployed airbag.
6. Always wash your hands with water after completing the operation.
7. Do not apply water, etc. to a steering wheel pad with deployed airbag.
AIRBAG DEPLOYMENT PROCEDURE
(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 approx. 30 sec-
onds or lo nger from the time the ignition switch is turned
to the LOCK position and the negative (±) terminal cable
is disconnected from the battery (See page AB±2).
±
SRS AIRBAG Disposal of Steering Wheel Pad (with Airbag)AB±91
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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 scr apping which has a
steering wheel pad with deployed airbag, use gloves
and safety glasses.
AIRBAG DEPLOYMENT PROCEDURE
(PROCEDURE FOR DISPOSAL OF
STEERING WHEEL PAD ONLY)
When disposing of the steering wheel pad (with airbag)
only, never use the customer's vehicle to deploy the
airbag.
Remove the steering wheel pad from the vehicle 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 STEERING WHEEL PAD (SEE PAGE AB±16)
CAUTION:
wWhen removing the steering wheel pad (with
airbag), work must be started after approx. 30
seconds or longer 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.
2. REMOVE STEERING WHEEL PAD CONNECTOR
Remove the connector on the steering wheel pad rear
surface from the inflater cover.
±
SRS AIRBAG Disposal of Steering Wheel Pad (with Aribag)AB±93
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wAlways tie down the steering wheel pad with the pad
side facing upward. It is very dangerous if the steer-
ing 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:
w The disc wheel will be marked by airbag deployment, so
use a redundant disc wheel.
4. CONFIRM FUNCTIONING OF SST (SEE PAGE AB±94)
SST 09082±0700
5. INSTALL SST CAUTION: Place the disc wheel on level ground.
(a) Connect 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.
6. COVER STEERING WHEEL PAD WITH CARDBOARD BOX 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
20 kg (44 lb, 196 N).
Size of cardboard box: Must exceed the following dimen-
sions ±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.
±
SRS AIRBAG Disposal of Steering Wheel Pad (with Aribag)AB±95
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GENERAL DESCRIPTION
The LEXUS SC400 is equipped with an SRS (Supplemental Restraint System) a\
irbag.
Failure to carry out service operations in the correct sequence could cause the\
airbag system to unex-
pectedly deploy during servicing, possibly leading to a serious accident.
Further, if a mistake is made in servicing the airbag system, it is possible the\
airbag may fail to operate
when required.
Before performing servicing (including removal or installation of parts, insp\
ection or replacement), be
sure to read the following items carefully, then follow the correct procedure described in the repair
manual.
1. Malfunction symptoms of the airbag system are difficult to confirm, so the diagnostic codes become themost important source of information when troubleshooting.
When troubleshooting the airbag system, always inspect the diagnostic co\
des before disconnecting the
battery (See page AB±25).
2. Work must be started after approx. 20 seconds or longer from the time the ig\
nition switch is turned to the LOCK position and the negative (±) terminal cable is disconnec\
ted from the battery. (The
airbag system is equipped with a back±up power source so that if work is sta\
rted within 20 seconds
of disconnecting the negative (±) terminal cable of the battery, the airbag may be deployed.)
When the negative (±) terminal cable is disconnected from the battery, memory of the clock and audio sys-
tems will be cancelled. So before starting work, make a record of the conten\
ts memorized by the audio
memory system. Then when work is finished, reset the audio systems as before a\
nd adjust the clock. When
the vehicle has power tilt and power telescopic steering, power seat, power \
outside rear view mirror and
power shoulder belt anchorage, which are all equipped with memory function, it\
is not possible to make
a record of the memory contents. So when the work is finished, it will be\
necessary to explain this fact to
the customer, and ask the customer to adjust the features and reset the memory. To avoid erasing the
memory of each memory system, never use a back±up power supply from outside\
the vehicle.
3. Even in cases of a minor collision where the airbag does not deploy, the front airbag sensors and
the steering wheel pad should be inspected (See page AB±9).
4. Never use airbag parts from another vehicle. When replacing parts, replace them with new parts.
5. Before repairs, remove the airbag sensors if shocks are likely to be applied to the sensors during repairs.
6. Never disassemble and repair the front airbag sensors, center airbag sensor a\
ssembly or steering
wheel pad in order to reuse it.
7. If the front airbag sensors, center airbag assembly or steering wheel pa\
d have been dropped, or if there are cracks, dents or other defects in the case, bracket or conn\
ector, replace them with new
ones.
8. Do not expose the front airbag sensors, center airbag sensor assembly or\
steering wheel pad directly to hot air or flames.
9. Use a volt/ohmmeter with high impedance (10 kW/V minimum) for troubleshoo\
ting of the electrical circuit.
10. Information labels are attached to the periphery of the airbag components. Follow t\
he instructions
on the notices.
11. After work on the airbag system is completed, perform the airbag warning\
light check (See page AB±30 ).
AB±2
SRS AIRBAG
± General Description
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FRONT AIRBAG SENSOR
1. Never reuse the front airbag sensors involved in a collisionwhen the airbag has deployed. (Replace both the left and
right airbag sensors.)
2. Install the front airbag sensor with the arrow on the sensor facing toward 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 sensor is equipped with an electrical connection check mechanism. Be sur\
e 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 AB±7).
SPIRAL CABLE (in COMBINATION SWITCH)
The steering wheel must be fitted correctly to the steering column with the\
spiral cable at the neutral posi-
tion, otherwise cable disconnection and other troubles may result. Refer to pa\
ge AB±17 of this manual con-
cerning correct steering wheel installation.
STEERING WHEEL PAD (with AIRBAG)
1. When removing the steering wheel pad or handling a new steering wheel pad, it should be placed with the pad top
surface facing up.
In this case, the twin±lock type connector lock lever should be
in the locked state and care should be taken to place it so the
connector will not be damaged. And do not store a steering
wheel pad on top of another one. (Storing the pad with its me-
tallic surface up may lead to a serious accident if the airbag
inflates for some reason.)
2. Never measure the resistance of the airbag squib. (This may cause the airbag to deploy, which is very dangerous.)
AB±3SRS AIRBAG ± General Description
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