Mercedes-Benz G-Class Operator's Manual page 52

Occupant safety
50
Method of operation
During the first stage of a collision, the
restraint system control unit evaluates impor-
tant physical data relating to vehicle deceler-
ation or acceleration, such as:
duration
R
direction
R
intensity
R
Based on the evaluation of this data, the
restraint system control unit triggers the
Emergency Tensioning Devices during a fron-
tal or rear collision.
An Emergency Tensioning Device can only be
triggered, if:
the ignition is switched on.
R
the components of the restraint system are
R
operational; see "Restraint system warning
lamp" ( page 41)
Y
the belt tongue is engaged in the buckle on
R
the respective front-passenger seat
The Emergency Tensioning Devices in the
rear compartment are triggered independ-
ently of the lock status of the seat belts.
If the restraint system control unit detects a
more severe accident, further components of
the restraint system are activated independ-
ently of each other in certain frontal collision
situations:
Driver's air bag
R
Front-passenger front air bag
R
The front-passenger front air bag is activated
or deactivated depending on the person on
the front-passenger seat. The front-
passenger front air bag can only deploy in an
accident if the PASSENGER AIR BAG OFF indi-
cator lamp is off. Observe the information on
the PASSENGER AIR BAG OFF indicator lamp
( page 42).
Y
Your vehicle has a two-stage driver's air bag.
During the first deployment stage the driver's
air bag fills with sufficient propellant gas to
reduce the risk of injuries. The front air bag is
fully deployed with the maximum amount of
propellant gas if a second deployment thresh-
old is reached within a few milliseconds.
The activation threshold of the Emergency
Tensioning Devices and the air bag are deter-
mined by evaluating the rate of vehicle decel-
eration or acceleration which occurs at vari-
ous points in the vehicle. This process is pre-
emptive in nature. Deployment should take
place in good time at the start of the collision.
The rate of vehicle deceleration or accelera-
tion and the direction of the force are essen-
tially determined by:
the distribution of forces during the colli-
R
sion
the collision angle
R
the deformation characteristics of the vehi-
R
cle
the characteristics of the object with which
R
the vehicle has collided
Factors which can only be seen and measured
after a collision has occurred do not play a
decisive role in the deployment of an air bag.
Nor do they provide an indication of air bag
deployment.
The vehicle can be deformed considerably,
without an air bag being deployed. This is the
case if only parts which are relatively easily
deformed are affected and the rate of decel-
eration is not high. Conversely, air bags may
be deployed even though the vehicle suffers
only minor deformation. This is the case if, for
example, very rigid vehicle parts such as lon-
gitudinal body members are hit, and sufficient
deceleration occurs as a result.
If the restraint system control unit detects a
side impact or if the vehicle rolls over, the
applicable components of the restraint sys-
tem are activated independently of each
other depending on the apparent type of acci-
dent. If the system determines a need for
additional protection for the vehicle occu-
pants, the Emergency Tensioning Devices are
triggered.
Window curtain air bag on the side of
R
impact, independently of the use of the