1996 TOYOTA LAND CRUISER Workshop Manual

RS0OZ−02
−
SUPPLEMENTAL RESTRAINT SYSTEM SRS AIRBAG
RS−1
1100
Author: Date:
1996 LAND CRUISER (RM451U)
SRS AIRBAG
PRECAUTION
NOTICE:
The LAND CRUISER is equipped with an SRS , which comprises a driver airbag \
and a front pas-
senger airbag. Failure to carry out service operations in the correct sequence could cause the
SRS to unexpectedly deploy during servicing, possibly leading to a serio\
us accident. Further,
if a mistake is made in servicing the SRS, it is possible the SRS may fail to\
operate when re-
quired. Before performing servicing (including removal or installation \
of parts, inspection or
replacement), be sure to read the following items carefully, then follow the correct procedure
described in the repair manual.
Malfunction symptoms of the SRS are difficult to confirm, so the DTCs become the mos\
t impor-
tant source of information when troubleshooting. When troubleshooting th\
e SRS, always in-
spect the DTCs before disconnecting the battery.
Even in cases of a minor collision where the SRS does not deploy, the steering wheel pad, front
passenger airbag assembly, and airbag sensor assembly should be inspected (See pages
RS−9 , RS−23 and RS−34 )
Never use SRS parts from another vehicle. When replacing parts, replace them with \
new parts.
Never disassemble and repair the steering wheel pad, front passenger airbag assembly , or air-
bag sensor assembly in order to reuse it.
If the steering wheel pad, front passenger airbag assembly or airbag sen\
sor assembly have
been dropped, or if there are cracks, dents or other defects in the case, br\
acket or connector,
replace them with new ones.
Use a volt/ohmmeter wi th high impedance (10 k Ω/V minimum) for troubleshooting the system’s
electrical circuits.
Information labels are attached to the periphery of the SRS components. Follow the instruc-
tions on the notices.
After work on the SRS is completed, check the SRS warning light (See pa\
ge DI−240).
If the vehicle is equipped with a mobile communication system, refer to the precaution in the
IN section.
CAUTION:
Work must be started after 90 seconds from the time the ignition switch is t\
urned to the ”LOCK”
position and the negative ( −) terminal cable is disconnected from the battery.
(The SRS is equipped with a back− up power source so that if work is started within 90 seconds
of disconnecting the negative ( −) terminal cable of the battery, the SRS may be deployed.)
When the negative (−) terminal cable is disconnected from the battery, the memory of the clock
and audio system will be canceled. So before starting work, make a record o\
f the contents mem-
orized in the audio memory system. When work is finished, reset the audio syst\
ems as they
were before and adjust the clock. To avoid erasing the memory of each memory system, never
use a back−up power supply from outside the vehicle.
Before repairs, remove the airbag sensor if shocks are likely to be applied to the senso\
r during
repairs.
Do not expose the steering wheel pad, front passenger airbag assembly, or airbag sensor as-
sembly directly to hot air or flames.
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RS0P0−01
AB0250Spiral Cable
R13451
RS−2
−
SUPPLEMENTAL RESTRAINT SYSTEM SRS AIRBAG
1996 LAND CRUISER (RM451U)
OPERATION
1. STEERING WHEEL PAD (with AIRBAG)
The inflater and bag of the SRS are stored in the steering wheel
pad and cannot be disassembled. The inflater contains a squib,
igniter charge, gas generant, etc., and inflates the bag when
instructed by the airbag sensor assembly.
2. SPIRAL CABLE (in COMBINATION SWITCH)
A spiral cable is used as an electrical joint from the vehicle body
side to the steering wheel.
3. FRONT PASSENGER AIRBAG ASSEMBLY
The inflater and bag of the SRS are stored in the front passen-
ger airbag assembly and cannot be disassembled.The inflater
contains a squib, igniter charge, gas generant, etc., and inflates
the bag when instructed by the airbag sensor assembly.
4. SRS WARNING LIGHT
The SRS warning light is located on the combination meter. It
goes on to alert the driver of trouble in the system when a mal-
function is detected in the airbag sensor assembly. In normal
operating condition when the ignition switch is turned to the
ACC or ON position, the light goes on for about 6 seconds and
then goes off.
5. AIRBAG SENSOR ASSEMBLY
The airbag sensor assembly is mounted on the floor inside the
console box. The airbag sensor assembly consists of an airbag
sensor, safing sensor, diagnosis circuit and ignition control,
drive circuit, etc.
It receives signals from the airbag sensors and judges whether
the SRS must be activated or not.
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R11937
Airbag Sensor
Assembly
Spiral
Cable
Front Passenger
Airbag Assembly
Steering Wheel
Pad
Instrument Panel
Junction Block Junction
Block No. 1
−
SUPPLEMENTAL RESTRAINT SYSTEM SRS AIRBAG
RS−3
1996 LAND CRUISER (RM451U)
6. SRS CONNECTORS
No.ItemApplication
(1)Terminal Twin−Lock MechanismConnectors 1, 2, 3, 4, 5, 6, 7
(2)Airbag Activation Prevention MechanismConnectors 2, 3, 4
(3)Electrical Connection Check MechanismConnectors 1
(4)Connector Twin −Lock MechanismConnectors 2, 3, 4
(a) All connectors in the SRS are colored yellow to distin-
guish them from other connectors. Connectors having
special functions and specifically designed for the SRS
are used in the locations shown above to ensure high reli-
ability. These connectors use durable gold −plated termi-
nals.
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Z05953
SpacerHousing
Female Male
R10587
 When Connector is Connected
 When Connector is Disconnected
Short Spring Plate Short Spring Plate
Contacting M ale Terninal
Short Spring Plate ON
Housing
Connectors Short Spring PlateSquib
Closed CircuitSquib
Housing
Terminal
RS−4
−
SUPPLEMENTAL RESTRAINT SYSTEM SRS AIRBAG
1996 LAND CRUISER (RM451U)
(1) Terminal Twin −Lock Mechanism
Each connector has a two −piece construction con-
sisting of a housing and a spacer. This design se-
cures the locking of the terminal by two locking de-
vices (the retainer and the lance) to prevent
terminals from coming out.
(2) Airbag Activation Prevention Mechanism
Each conn ector contains a short spr ing plate. When
the connector is disconnected, the short spring
plate automatically connects the power source and
grounding terminals of the squib.
HINT:
The type of connector shown above is used for connectors 2,
3 and 4 in the diagram on the preceding page.
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R13061
 Half Connection 
Comlate Connection
Terminal of Diagnosis Terminal of Diagnosis
Disconnection Detection Pin
−
SUPPLEMENTAL RESTRAINT SYSTEM SRS AIRBAG
RS−5
1996 LAND CRUISER (RM451U)
(3) Electrical Connection Check Mechanism
This mechanism electrically checks if connectors
are connected correctly and completely. The electri-
cal connection check mechanism is designed so
that the disconnection detection pin connects with
the diagnosis terminals when the connector hous-
ing lock is locked.
HINT:
The illustration shows connector 1.
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Z05490
Secondary LockPrimary Lock Lock Lock
Primary Lock Incomplate
(Secondary Lock Prevended) Primary Lock Complate
(Secondary Lock Permitted
Twin−Lock Complated
Z14034
Fig.1
Fig.2 Power Source
SafingSensor Squibs
Airbag
Sensor
RS−6
−
SUPPLEMENTAL RESTRAINT SYSTEM SRS AIRBAG
1996 LAND CRUISER (RM451U)
(4) Connector Twin −Lock Mechanism
With this mechanism connectors (male and female
connectors) are locked by 2 locking devices to in-
crease connection reliability. If the primary lock is in-
complete, ribs interfere and prevent the secondary
lock.
(b) When the vehicle is involved in a frontal collision in the hatched area (Fig. 1) and the shock is larger than the pre-
determined level, the SRS is activated automatically. A
safing sensor is designed to go on at a smaller decelera-
tion rate than the airbag sensor. As illustrated in Fig. 2,
ignition is caused when current flows to the squib, which
happens when a safing sensor and the airbag sensor go
on simultaneously.When a deceleration force acts on the
sensors, two squibs in the driver airbag and front passen-
ger airbag ignite and generate gas. The gas discharging
into the driver airbag and front passenger airbag rapidly
increases the pressure inside the bags, breaking open
the steering wheel pad and instrument panel door.
Bag inflation then ends, and the bags deflate as the gas
is discharged through discharge holes at the bag’s rear or
side.
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RS0P1−01
−
SUPPLEMENTAL RESTRAINT SYSTEM STEERING WHEEL PAD AND SPIRAL CABLE
RS−7
1106
Author: Date:
1996 LAND CRUISER (RM451U)
STEERING WHEEL PAD AND SPIRAL CABLE
COMPONENTS
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RS0P2−01
RS−8
−
SUPPLEMENTAL RESTRAINT SYSTEM STEERING WHEEL PAD AND SPIRAL CABLE
1996 LAND CRUISER (RM451U)
REMOVAL
REMOVE STEERING WHEEL AND SPIRAL CABLE (See page SR−11)
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