function for the vehicleoccupants in the event
of acrash.
G
WARNING
Emergency Tensioning Devices that have
deployedpyrotechnically are no longer
operational and are unable to perform their
intended protective function. This posesan
increased risk of injury or even fatal injury.
Have pyrotechnically triggered Emergency
Tensioning Devices replaced immediately at
aqualified specialist workshop.
An electric motor is usedbyPRE-SAFE
®
to
trigger the tightening of the seatbeltinhaz-
ardous situations. This procedure is reversible.
If Emergency Tensioning Devices are triggered
or air bagsare deployed, you willhearabang,
and some powder may alsobereleased. The
6 restraint system warning lamplights up.
Only in rare cases willthe bang affect your
hearing. The powder that is releasedgenerally
does not constitute ahealth hazard, but it may
causeshort-term breathing difficulties in peo-
ple with asthma or other respiratory problems.
Provided it is safe to do so, you should leave
the vehicleimmediately or open the window in
order to prevent breathing difficulties.
Air bagsand pyrotechnic Emergency Tension-
ing Devices (ETDs) contain perchlorate mate-
rial,which may require special handling and
regard for the environment. National guide-
lines must be observed during disposal.InCal-
ifornia,see www.dtsc.ca.gov/
HazardousWaste/Perchlorate/index.cfm.
Method of operation
During the first stage of acollision, the
restraint system control unit evaluates impor-
tant physical data relating to vehicledecelera-
tion or acceleration, such as:
R
duration
R
direction
R
intensity
Based on the evaluation of this data,the
restraint system control unit triggersthe Emer-
gency Tensioning Devices during ahead-on or
rear-end collision.
An Emergency Tensioning Device can only be
triggered, if:
R
the ignition is switched on
R
the components of the restraint system are
operational.You can find further information
under "Restraint system warning lamp"
(Y page39)
R
the seatbeltbuckle tongue has engaged in
the beltbuckle of the respective seat
If the restraint systemcontrol unit detects a
more severe accident, further components of
the restraint systemare activated independ-
ently of each other in certain frontal collision
situations:
R
Front air bagsaswellasdriver's and front-
passenger knee bags
Depending on the personinthe front-
passenger seat, the front-passenger front air
bag is either enabled or disabled. The front-
passenger front air bag can be deployedinan
accident only if the PASSENGER AIR BAG OFF
indicator lampisoff. Observe the information
on the PASSENGER AIR BAG indicator lamps
(Y page39).
Yourvehiclehas two-stage front air bags.
The activation thresholdofthe Emergency
Tensioning Devices and the air bagsisdeter-
mined by evaluating the rate of vehicledecel-
eration or acceleration which occurs at various
points in the vehicle. This process is pre-emp-
tive in nature. Deployment should take place
in good time at the start of the collision.
The rate of vehicledeceleration or accelera-
tion and the direction of the force are essen-
tially determined by:
R
the distribution of forces during the collision
R
the collision angle
R
the deformation characteristics of the vehi-
cle
R
the characteristics of the object with which
the vehiclehas collided
Factors which can only be seen and measured
after acollision has occurred do not playa
decisive role in the deployment of an air bag.
Nor do they provide an indication of air bag
deployment.
The vehiclecan be deformedconsiderably,
without an air bag being deployed. This is the
case if only parts which are relatively easily
deformedare affected and the rate of deceler-
ation is not high.Conversely,air bagsmay be
deployedeven though the vehiclesuffers only
Occupant safety
51
Safety
Z
