2750973 - 5580C air bag system
The following figure shows the
complete configuration of the Air Bag system.1 - Electronic control unit
2 - Key switch for disabling the passenger's front Air Bag
3 - Passenger's Air Bag module
4 - Passenger's Side Bag module
5 - Passenger seat belt pretensioner
6 - Side impact satellite sensor
7 - Passenger's Window Bag module
8 - Driver's Window Bag module
9 - Side impact satellite sensor
10 - Driver's pretensioner
11 - Driver's Side Bag module
12 - Driver's Air Bag module
13 - Air Bag system failure warning light
14 - Passenger's front Air Bag deactivation warning light
The system is not equipped with
a passenger presence sensor
The Air Bag system used on the
car intervenes, in the case of front or side impacts of medium-high
severity, to protect the occupants of the front seats and the heads
of the occupants of the side rear seats. The system is completed
by the presence of pretensioners on the front seat belts which,
to optimise their retaining action, have a load limiter.So that the Air Bag system can carry out
its function with the maximum efficiency, the seat occupants MUST
wear their seat belts correctly.The front airbags are all single-stage,
i.e. with only one charge per module. | The components of the Air Bag
system have been designed to work on a specific car. They therefore
may NOT be tampered with, adapted or installed on other types of
vehicles. Any attempt to reuse, adapt or install them on a different
type of vehicle could cause severe or fatal injury to the occupants,
both in the case of normal use and in the event of a crash. |
A control system managed by the electronic
control unit, in the case of a front or side impact, controls the
partial or total activation of the devices.The Air Bag system components are connected
electrically by dedicated wiring, integrated in the dashboard wiring
loom for the front devices, and in the rear wiring loom for the
side devices.The control unit is connected to the system
by means of two connectors, one for the front cable and one for
the rear cable.The passenger's front Air Bag module can
be deactivated voluntarily, by a specific key switch located beside
the dashboard. The deactivation of the passenger's front Air Bag
module does not disable the side Air Bag modules. Thus in the evente
of a side impact, protection is also offered to any child who may
be on board. | For safety reasons continuity
checks on the wiring are NOT permitted. To consult the electrical
diagram of the system's connections, see E7030. |
| GRAVE DANGER! If a child seat
is fitted on the front passenger seat, the front Air Bag module
MUST be deactivated. |
| If the module is deactivated,
a passenger seated on the front seat is protected, in the event
of a crash, only by the seat belt with pretensioner and the side
Air Bags. |
| the activation of the Air Bags
releases a small amount of powder. This powder, which may be deposited
on the opened cushions and inside the vehicle, is not harmful but
could irritate the skin and eyes. In case of exposure, wash with
neutral soap and water. |
| The Air Bags may be activated
if the car is subjected to strong impacts or accidents involving
the underbody, for example violent collisions with steps, fixed
projections on the ground or the vehicle falling into large holes
or hollows. |
To indicate the state of efficiency,
the system has:
- fault warning light (red) on the instrument panel;
- passenger's Air Bag disabled warning light (yellow)
on the instrument panel;
- serial diagnostic serial, integrated in the EOBD socket,
for checking efficiency using the EXAMINER.
| In the case of a change of ownership,
it is essential for the new owner to be informed about the above
methods of use and warnings, and be given the Owner's Handbook. |
The Air Bag protection system comprises
the following:
- an electronic control unit;
- two side impact sensors (right and left);
- a switch for disabling the passenger's Air Bag;
- two front Air Bag modules for protecting the front seat
occupants;
- two side protection Air Bag modules (chest, abdomen)
for the front seat occupants;
- two side Air Bag modules protecting the heads of the
front seat occupants and the rear side seats.
- two seat belts with pretensioners on the front seats.
ELECTRONIC CONTROL UNIT
The control unit is located on
the car floor near the climate control unit
Specifications
The electronic control unit manages
the entire system, checking all the components, and has the function
of recognising a crash situation promptly and activating only the
pretensioners or the pretensioenrs and the Air Bag modules, depending
on the type and severity of the crash.The control unit is fixed rigidly to the
bodywork, under the central console near the centre of gravity,
to allow the deceleration sensors it contains to detect precisely
the deceleration of the car. | The control unit must always be
fitted with the arrow stamped on the adhesive plate facing the vehicle's
direction of travel. Always check that there are no foreign bodies
between the control unit and the bodywork, and tighten the bolts
to the specified torque. |
Components
The following figure shows the
control unit.A - 24-way connector M060A for front cable
B - 24-way connector M060A for rear cable
C - Control unit
D - Identification plate
Components
Connector A Pin Out| Conn. | Pin | Operation |
|---|
| M060A | relay | Earth |
| M060A | relay | Supply + 15 |
| M060A | 3 | Serial interface K line |
| M060A | 4 | N.C. |
| M060A | 5 | N.C. |
| M060A | 6 | Crash output |
| M060A | 7 | Passenger airbag inhibition switch |
| M060A | 8 | N.C. |
| M060A | 9 | Passenger Air Bag deactivation warning light |
| M060A | 10 | Failure warning light |
| M060A | 11. | N.C. |
| M060A | 12. | N.C. |
| M060A | 13 | N.C. |
| M060A | 14 | N.C. |
| M060A | 15 | N.C. |
| M060A | 16 | N.C. |
| M060A | 17 | N.C. |
| M060A | 18 | N.C. |
| M060A | 19 | N.C. |
| M060A | 20 | N.C. |
| M060A | 21 | Driver's airbag + |
| M060A | 22 | Driver's airbag- |
| M060A | 23 | Passenger airbag+ |
| M060A | 24 | Passenger airbag- |
Connector B pinout| Conn. | Pin | Operation |
|---|
| M060B | relay | Driver's side sensor + |
| M060B | relay | Driver's side sensor - |
| M060B | 3 | Passenger's side sensor- |
| M060B | 4 | Passenger's side sensor+ |
| M060B | 5 | N.C. |
| M060B | 6 | N.C. |
| M060B | 7 | N.C. |
| M060B | 8 | N.C. |
| M060B | 9 | N.C. |
| M060B | 10 | N.C. |
| M060B | 11. | N.C. |
| M060B | 12. | N.C. |
| M060B | 13 | Driver's pretensioner + |
| M060B | 14 | Driver's pretensioner - |
| M060B | 15 | Passenger pretensioner - |
| M060B | 16 | Passenger pretensioner + |
| M060B | 17 | Driver's window bag + |
| M060B | 18 | Driver's window bag - |
| M060B | 19 | Passenger window bag - |
| M060B | 20 | Passenger's window bag + |
| M060B | 21 | Driver's side bag + |
| M060B | 22 | Driver's side bag - |
| M060B | 23 | Passenger sidebag - |
| M060B | 24 | Passenger side bag + |
The control unit contains two deceleration
sensors, one electronic and the other an electromechanical safety
sensor which has the function of giving enablement to activation,
working independently from the electronic sensor.If the car's deceleration value, measured
by the electronic sensor and processed by the processor in terms
of severity of the crash, exceeds the severity level established
for the command to activate the devices, the control unit makes
sure that this command can only be sent if, at the same time, the
safety sensor is closed.To ensure the correct management
of the system, the following functions are present:
- accumulation of energy: the control unit is supplied
at 12V with key in the ON position, but can operate for a few fractions
of a second if the supply voltage is interrupted or drops, so as
to ensure operation of the system and write the data in the crash
memory.
- fault memory: with the ignition on, the control unit
continuously checks that the circuit is working (including the energy reserve
circuit), during normal operation of the car and during normal operation
of the car and during any crashes, and tests all the electrical
parts of the system, indicating the presence of faults by switching
on the Air Bag fault warning light on the instrument panel and memorising
the fault code.
- crash memory: this records the information, relating
to crash events, which have led to the activation of the pretensioners and
modules, front or side.
In view of the importance of its functions,
the control unit is designed in such a way that it cannot be opened
with leaving visible signs of having been tampered with. | If the control unit is dropped
or is subjected to unusual impact during handling, the control unit
MUST be replaced. |
Operation
In the case of a frontal impact,
the electronic sensor detects a deceleration signal along the vehicle's
longitudinal axis. If the signal, processed by the control unit's
processor, indicates a crash severity such as to require the intervention
of the system and if, at the same time, the safety sensor is closed
(enablement for activation), the control unit, as the first intervention
level, commands the activation of only the pretensioners or, in
the case of a more severe impact, the pretensioners and front Air Bags
(activation of driver's module only if the passenger's module has
been deactivated).As with a side impact, the satellite sensors,
located in the central pillars, detect the direct crash signal along
the car's transversal axis, and send it to the control unit. If
the severity of the crash is such as to require the system's intervention,
if the information from the satellite sensors corresponds to that
from the safety sensor, the control unit commands the activation of
the modules on the side affected by the crash. The side modules
are activated independently of each other (driver's or passenger's)
and of the front modules.The activation of the front Air Bags is
always preceded by the activation of the pretensioners, unless the
pretensioners have been activated in a previous crash and have not
yet been replaced.The system activation times are in the order
of thousandths of a second and anticipate the movements of the occupant's
body following the impact.After each activation of one of the systems
operated (pretensioners, front Air Bags, side Air Bags), the control
unit memorises the activation in non-deletable memory and causes
the fault warning light on the instrument panel to come on.Before being replaced, the control
unit guarantees the activation of the individual devices within
the following limits:
- 3 impacts with activation of the front seat belt pretensioners
only;
- 3 impacts in total with activation of the side Air Bags
(right or left)
- 1 impact with activation of the pretensioners and front
Air Bags;
- any combination of the above cases until one of the
limits indicated is reached.
If one of the limits described has not been
reached, it will be possible, after restoring the operating conditions
of the system, to reuse the control unit after carrying out the
RESET procedure by means of the EXAMINER. The last activation, for
each of the sequences, will prevent further reset conditions. | The Air Bag system does not intervene
in the case of a rear collision or if the vehicle overturns. |
System autodiagnosis
The control unit carries out a continuous
self-test of the system's operation. In particular:
- it detects and memorizes any faults
- it recognizes the various components and the type of
fault;
- it signals the onset of these faults via the special
warning light in the instrument panel.
The faults memorised in the control unit
may only be deleted after the fault has been repaired using the
EXAMINER diagnostic equipment. | If a fault is detected in the
passenger Air Bag disabling switch, for safety reasons this is considered
by the control unit to be in the OFF position, so the operation
of the module is inhibited and the warning light on the instrument panel
comes on. |
AIR BAG SYSTEM FAILURE WARNING LIGHT
View of position on instrument
panel
Specifications
During starting, key in key-on
position, the fault warning light (red) comes on for about four
seconds (initial self-test stage) and then goes out. If the control
unit detects a fault in the warning light, it memorises the corresponding
fault code. If no faults are detected in the system at key-on, and
there are no fault conditions in the fault memory, the warning light
goes out after four seconds of self-test, otherwise it stays on
until key off. In this case, the fault message also changes on the
display (if present) 10 s after receiving a command from the CAB.The airbag warning light is controlled
directly from the Airbag control unit (CAB). The CAB is not connected
via the CAN.Messages on the display (where present)
are managed by the Instrument Panel Node.
Operation
The warning light remains on or comes
on, during the normal operation of the vehicle (with a fault message
on the display if present), in the following cases:
- the control unit detects a fault in the Air Bag system;
- the control unit detects an impact with activation of
the system;
- the control unit detects a fault in the actual warning
light connection circuit.
As a result of an impact with the intervention
of only the pretensioners or side Air Bags, the warning light stays
on until the system's operating conditions are restored (replacement
of the component concerned and rest of the control unit using the EXAMINER).if the impact causes the intervention of
the front Air Bag modules, the warning light stays on permanently,
and the control unit cannot be reset (in this case the control unit
must be replaced).If internal operating faults arise during
the control unit's operating life, and these faults cannot be reset
by the EXAMINER, they are indicated by the warning light staying
on permanently.
PASSENGER'S FRONT AIR BAG DISABLED WARNING LIGHT
View of position on instrument
panel
Specifications
With the key at the key-on position,
the passenger's Air Bag disabled warning light (yellow) comes on
for about four seconds (initial self-test stage). If the control
unit detects a fault in the warning light, it memorises the relevant
fault code, switches on the fault warning light and keeps the passenger's
Air Bag module disabled. Restore the system's operation using the EXAMINER,
in the same way as for the fault warning light.After the initial four-second self-test
stage, if the disabling key switch is turned to the OFF position,
the warning light stays on indicating that the passenger's module
is disabled. If there are no faults, the light flashes for a further
four seconds and then goes out, indicating that the passenger's
module is enabled. | The passenger's module MUST be
disabled only using the ignition key (ignition switch at STOP position)
- (DO NOT USE a second ignition key for disablement). |
DRIVER'S AIR BAG MODULE
The following figure shows a
view of the assembly1 - Horn connector
2 - Horn contacts
3 - Connection point to the electrical system
4 - Housing
5 - Bag fastening plate
6 - Retaining ring
7 - Gas generator
8 - Nut
9 - Bag
10 - Cover
Specifications
The driver's airbag module is
snap-in, i.e. the module is fastened to the steering wheel by a
spring clip without retaining bolts.The Air Bag is a passive safety device made
up of a bag which, in the case of a frontal impact, automatically
inflates placing itself between the body of the driver and the structure
of the front part of the passenger compartment. The Air Bag module is
installed in the centre of the steering wheel, and its cover also
acts as the horn control.
Components
The module comprises:
- a plastic cover; which in the case of activation tears
in predefined points to allow the bag to expand correctly;
- a bag, with a volume of about 55 litres, made of nylon
fabric to minimise skin abrasions in the case of contact, and folded in
a particular way so that it inflates gradually and not directly
facing the driver;
- a pyrotechnic gas generator
- a casing.
On the bottom of the gas generator, there
is a warning plate which gives the instructions for handling (see
PROCEDURE 5580C).
Operation
The gas generator for inflating
the module is electrically activated by a signal coming from the
electronic control module. Following this signal, a pyrotechnic
charge contained in the generator is triggered. The gases produced
by the combustion of the charge flow through special holes and expand
in the bag, causing the cover to tear at the specific points. When
fully inflated, the cushion is in the optimum position to carry
out its function to retain the occupant. After being inflated by
the gas, the bag deflates immediately through specific vent holes.
CLOCK SPRING
The following figure shows a
view of the assemblyA - Front view of the stalk unit
B - Lower view of the stalk unit
C - Clock spring
1 - Electrical connection for connecting horn
2 - Electrical connection for Air Bag
3 - Electrical connection for connecting radio controls
4 - Lower connector
Specifications
The Clock Spring is a device
which allows the connecting cables for the Air Bag module and other
electrical controls installed in the steering wheel to follow the
steering wheel rotation without the risk of breaking.The device, consisting of two plates is
secured by means of the lower plate to the stalk unit, and is joined
to the steering wheel by means of specific recesses on the upper
plate. The connection to the electrical system is via the connection
points, present on the edge of the lower plate.
Components
The clock spring has three cables
on the steering wheel side, one of which is for connecting the Air
Bag module. Once connects the steering wheel radio controls and
the other connects the horn.On the upper plate, steering wheel side,
there is a ring which automatically blocks the rotation between
the two plates when the device is removed from the steering wheel.The new device is supplied with a safety
key for transport, to be removed before fitting.
Operation
Inside the two plates, the connecting
cables for the Air Bag module and the various electrical functions
are wound in a spiral, with a sufficient number of coils to follow
the steering wheel's rotations. The upper plate rotates by means
of the recesses present inside the locking ring which fit in the
seating on the steering wheel hub. In the working position, the
steering wheel presses on the ring, freeing it from the recesses,
thus unlocking the rotation between the two plates. When the steering
wheel is removed, pushed by a spring, it blocks the rotation between
the two plates. This function prevents the top plate, no longer locked
to the steering wheel, from turning freely and causing the sprial
inside the device to unwind or wind and then possibly break.In operations involving the removal
of the steering wheel and the device, the following must be observed:
- always operate with the wheels lined up straight;
- for safety, lock the clock spring with a band before
removing it from the stalk unit.
| If for any reason the upper plate
rotates in relation to the lower plate so much that the original
position cannot be identified with absolute certainly, the clock
spring MUST be replaced (see PROCEDURE op. 5580C12). |
PASSENGER AIR BAG MODULE
The following figure shows a
view of the assembly1 - Bag cover
2 - Pre-established break lines
3 - Folded bag
4 - Gas generator
5 - Metal mount
6 - Connection point
Specifications
The passenger's Air Bag module
is located inside the dashboard, near a foam rubber flap in the
trim, above the glove compartment, and is secured by brackets to
the crossmember. As for the driver's module, it intervenes to provide
front protection for the passenger, in the event of crashes which
exceed a particular threshold, and can also be specifically disabled.
Components
The module comprises:
- a metal mounting containing the gas generator and bag;
- a plastic cover with preset break lines that allow the
bag to expand;
- a bag, with a volume of about 90 litres, made of nylon
fabric in order to minimise skin abrasions in the event of contact, and
folded in a particular way;
- a gas generator consisting of a pressurised gas container
holding a pyrotechnic charge;
- a point for connection to the electrical system;
a warning plate on the lower part of the
module gives the handling instructions (see PROCEDURE 5580C).
Operation
The gas generator for inflating
the module is electrically activated by a signal coming from the
electronic control module. Following this siganl, a pyrotechnic
charge is triggeed which causes the gases contained in the generator
to expand. The gases expand, coming out of specific holes, and inflate
the bag. The increase in volume of the bag causes the cover to break along
the preset lines, thus allowing the bag to emerge.When fully inflated, the cushion is in the
optimum position to carry out its function to retain the occupant.
After being inflated by the gas, the bag deflates immediately thanks
to the permeability of the fabric.
PASSENGER AIR BAG DISABLEMENT KEY SWITCH
The airbag disablement switch
is located inside the passenger side glove compartment (on the left
internal wall),1 - Key switch
2 - OFF position: passenger's Air Bag disabled
3 - ON position: passenger's Air Bag enabled
4 - Passenger's Air Bag disabled warning light
Specifications
A switch operated by the ignition
key allows the passenger's Air Bag module to be enabled (ON) or
disabled (OFF).
Components
The diagram below shows a view
of the assembly.1 - Casing
2 - Switch
3 - Key barrel
4 - Plate
Components
The unit consists of a casing
containing the switch, a key barrel inserted in the casing and held
by a clip and a plate which indicates the position assumed by the
switch (ON or OFF). On the casing, there is also the seating for
the connector to the electrical system.Any faults in the switch are indicated by
the Air Bag system fault warning light coming on.
Operation
The switch can be operated by
the car's ignition switch whenever the activation of the passenger's
front module is to be enabled or disabled.The electronic control unit checks the status
of the switch during the normal diagnostic procedure at Key On (four
seconds). If the recognised state is OFF, it excludes the module
from possible activation, memorises the corresponding signal and causes
the passenger Air Bag disabled warning light on the instrument panel
to come on. If the recognised state is ON, after the four seconds
of the diagnostic procedure the warning light flashes for a further
four seconds and then goes out.The remaining side airbags (window bag and
side bag) and pretensioners are not affected by the deactivation
command.In the case of faults in the switch,
the system ensures the following:
- it does not activate the passenger module
- it causes the Air Bag fault warning light to come on
- it causes the passenger Air Bag disabled warning light
to come on
- it memorises the state of deactivation.
| Do not operate the switch with
the ignition key in the ON position (e.g. by using the second key).
In this case the electronic control unit would memorise a fault,
indicating it by switching on the Air Bag fault warning light and deactivating
the module. |
Specifications
To provide maximum protection
to the front seat occupants in the event of side impacts, there
are side Air Bag modules installed on the seat squabs, on the side
facing the outside of the car, under the cover.This conformation is considered to be the
most efficient as it always enables the Air Bag to be in the optimum
position in relation to the occupant, irrespective of the seat adjustment
or size of the occupant.The side Air Bag mainly protects the chest
and abdominal region, even if the occupant is not seated correctly,
as the dynamics of opening of the bag minimises the risk of damage
to the body caused by the impact with the Air Bag. | Do not put covers on the front
seat squabs. |
| Do not wash the seat squab with
water or pressurised steam. |
Components
View of Side Bag components1 - Outer cover
2 - Container
3 - Point of electrical connection
4 - Gas generator
5 - Folded bag
6 - Warning plate
Components
The side Air Bag module consists
of a plastic container holding the gas generator and a permeable
nylon bag with a volume of about 12 litres.The module's container has a cover with
predetermined break zones which, with the seat squab cover fitted,
line up with easy-open sections of seam on the outside of the seat
cover.On the bottom of the container, there is
a warning plate which gives the instructions for handling the module
(see PROCEDURE 5580C).The module is connected to the electrical
system by means of two cables with a yellow coloured outer casing
housed, together with the earth connecting cable for the seat, in
a protective duct, secured to the seat structure.
Operation
The gas generator for inflating
the module is electrically activated by a signal coming from the
electronic control module. Following this siganl, a pyrotechnic
charge is triggeed which causes the gases contained in the generator
to expand. The gases expand, coming out of specific holes, and inflate
the bag. The increase in volume of the bag causes the container
to break in the predetermined areas and the seams on the seat squab
cover to open along the preset sections, thus enabling the bag to
come out correctly. After completion, the bag is in the optimum
position for carrying out its function of protecting the occupant.
After being inflated by the gas, the bag deflates immediately thanks
to the permeability of the fabric. | In the case of side impact, only
the sidebag module on the side affected by the impact is triggered. |
| No operations, other than removing
and refitting the seat from the vehicle, can be carried out on a
seats equipped with a Side Bag. It is absolutely prohibited to disassemble
seats fitted with a Side Bag; these operations should be carried
out by suitably trained and authorized personnel. |
Specifications
On some versions of the car,
there is a system for protecting the heads of the front and rear
side occupants.Apart from the vehicle's structural characteristics,
the Side Bags are the only passive protection system in the case
of a side impact. The head protection Air Bags (Window Bags), in
addition to the Side Bags and front Air Bags, offer the rear seat occupants
the maximum possible protection in the event of a crash, also eliminating
the risk of injuries to the arm and shoulder and protecting the
heads of the rear side seat occupants.Among the different types of Window Bag,
the curtain system is the one which offers the best performance
thanks to the large area of expansion and its self-supporting capacity,
also in the absence of support if the side windows break during
the impact.
Components
View of the Window Bag components1 - Anchoring strap
2 - Bag containing sleeve
3 - Bag retaining bands
4 - Generator fastening points
5 - Gas generator
6 - Warning plate
Components
The Window Bag module consists of:
- a gas generator secured by appropriate mounting to the
roof rail between the car's front and rear pillar;
- a bag, with a volume of about 26.5 litres, secured
to the gas generator and made of a nylon permeable fabric folded inside
a containing sleeve. The bag is designed so that, when inflated,
it correctly absorbs the energy of the impact, holding the heads
of the occupants an appropriate distance from the impact zone. Once
inflation is complete, the gas emerges immediately through the porous
cloth.
- Five plastic easy-open clamps secure the bag to the
ceiling longitudinal member;
- a retaining strap which holds the inflated bag in position;
- a connector for connection to the electrical system;
- a warning plate which gives the instructions [PR5580C].
Operation
The gas generator for inflating
the module is electrically activated by a signal coming from the
electronic control module. Following this siganl, a pyrotechnic
charge is triggeed which causes the gases contained in the generator
to expand. The gases expand and emerge through specific holes and
are distributed evenly along the length of the bag via the flexible
pipe, inflating the bag. The increase in volume of the bag causes
the fixing clamps to break, the sleeve seams to yield and the finishing
trim to open, designed so as to allow the bag to emerge correctly
downwards. The correct unfolding of the bag is ensured by a retaining
strap, present at the front end of the bag. After completion, the
bag is in the optimum position for carrying out its function of
protecting the occupant. After inflation, the bag deflates immediately
because of the permeability of the fabric. | In the case of side impact, only
the window bag on the side affected by the impact operates. |
SIDE IMPACT SATELLITE SENSORS
The sensors are located on the
two central pillars above the pretensioners.A - Connection
B - Locating pin
SIDE IMPACT SATELLITE SENSORS
Pin 1: satellite sensor signalPin 2: satellite sensor earth
Specifications
Apart from the Air Bags, the
side protection system also comprises the electronic control module
which ensures correct operation. To measure the acceleration resulting
from a side impact, there are two satellite sensors installed in
the side pillars, containing an accelerometer.
Components
The side impact satellite sensor
consists of a casing containing the acceleration sensor. At the
rear of the casing, there is a pin for correct positioning in the
seating. On the casing, there is also a connection point for connection
to the electrical system.
Operation
If the acceleration value measured
by the sensor in question causes a particular threshold to be exceeded,
this information is compared with the measurement obtained from
the safing sensor contained in the Air Bag system's electronic control
unit. If the values measured are consistent, the control unit causes
the activation of the Air Bags on the side affected by the impact. | In the case of side impact, the
pretensioner affected by the crash must be replaced. |
Specifications
The pretensioners are pyrotechnic
devices, electrically activated by a signal coming from the electronic
control unit, integrated in the front seat belt reel (the rear seat
belts are not fitted with pretensioners).Pretensioners are only fitted to the front
seat belt reelsThe intervention of the pretensioners in
the case of a frontal impact which exceeds a particular threshold,
causes any slack in the seat belt to be taken up, thus holding the
occupant as closely as possible to the seat squab. | The pretensioner operates only
if the seat belt is fastened. Otherwise it does not operate. No
passenger presence sensor is fitted. |
| Once the pretensioners have intervened,
the seat belts remain locked and must be replaced. |
1 - Gas generator
2 - Piston
3 - Rack
4 - Winder reel
5 - Seat belt
6 - Torsion bar
Operation
The pretensioner device consists
of a gas generator, housed in the structure, activated by an electrical
signal coming from the electronic control unit. The pressure of
the gas developed by the generator causes a piston to slide downwards
instantaneously. Built into the piston, there is a rack which engages
on the winder reel; the sliding of the rack causes the reel to rotate and
so the belt to rewind for a few centimetres. The pretensioners have
a load limiting device so that the load on the occupant's shoulder
during retention is gradual.
