Mercedes-Benz A-Class Operator's Manual page 40

38 38 Occupant safety
R R es estr traint syst aint system functionality em functionality
When the vehicle is switched on, a self-test is per-
formed, during which the 6 restraint system
warning lamp lights up. It goes out no later than a
few seconds a er the vehicle is started. The com-
ponents of the restraint system are then func-
tional.
Malfunctioning res estr traint syst Malfunctioning r aint system em
A malfunction has occurred in the restraint sys-
tem if:
The 6 restraint system warning lamp does
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not light up when the vehicle is switched on
The 6 restraint system warning lamp lights
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up continuously or repeatedly during a journey
& W W ARNING
ARNING Risk of injury due to malfunc-
tions in the restraint system
Components in the restraint system may be
activated unintentionally or not deploy as plan-
ned in an accident.
Have the restraint system checked and
#
repaired immediately at a quali ed spe-
cialist workshop.
F F unction of t unction of the r he res estr traint syst aint system in an accident em in an accident
How the restraint system works is determined by
the severity of the impact detected and the type
of accident anticipated:
Frontal impact
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Rear impact
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Side impact
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Rollover
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The activation thresholds for the components of
the restraint system are determined based on the
evaluation of the sensor values measured at vari-
ous points in the vehicle. This process is pre-emp-
tive in nature. The triggering/deployment of the
components of the restraint system must take
place in good time at the start of the collision.
Factors which can only be seen and measured
a er a collision has occurred do not play a deci-
sive role in the deployment of an airbag. Nor do
they provide an indication of airbag deployment.
The vehicle may be deformed signi cantly without
an airbag being deployed. This is the case if only
parts which are relatively easily deformed are
a ected and the rate of vehicle deceleration is
not high. Conversely, an airbag may be deployed
even though the vehicle su ers only minor defor-
mation. If very rigid vehicle parts such as longitu-
dinal members are hit, this may result in su -
ciently high levels of vehicle deceleration.
Depending on the detected deployment situation,
the components of the restraint system can be
activated or deployed independently of each
other:
Emergency Tensioning Device: frontal impact,
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rear impact, side impact, rollover
Driver's airbag, front passenger airbag: frontal
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impact
Knee airbag: frontal impact
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Side airbag: side impact
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Window curtain airbag: side impact, rollover,
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frontal impact