Mercedes-Benz E-CLASS 2009 Manual page 40

mkalafa,
Never tamper with electronic components
and their software.
SRS (Supplemental Restraint System)
The SRS reduces the risk of occupants com-
ing into contact with the vehicle's interior in
the event of an accident. It can also reduce
the forces to which occupants are subjected
during an accident.
The SRS consists of:
The 6 SRS warning lamp
R
belt tensioners
R
belt force limiters
R
airbags
R
The 6 6 SRS warning lamp
The SRS functions are checked regularly
when you turn on the ignition and when the
engine is running. Therefore, malfunctions
can be detected in good time.
The 6 SRS warning lamp in the instrument
cluster lights up when the ignition is switched
on. It goes out no later than a few seconds
after the engine is started.
G Risk of injury
If SRS is malfunctioning, individual systems
may be activated unintentionally or not be
deployed in the event of an accident with
heavy braking.
A malfunction has occurred if the 6 SRS
warning lamp:
does not light up when you switch on the
R
ignition
does not go out after the engine has been
R
running for a few seconds
lights up again once the engine is running
R
In this case, have SRS checked immediately
at a qualified specialist workshop.
Version: 2.11.8.1
Occupant safety
Triggering of belt tensioners, belt force
limiters and airbags
In the event of a collision, the airbag control
unit evaluates important physical data such
as duration, direction and force of the vehicle
deceleration or acceleration. Based on the
evaluation of this data and in the event of lon-
gitudinal deceleration in a collision, the airbag
control unit pre-emptively triggers the belt
tensioners, depending on the rate of deceler-
ation, in the first stage.
i
The front belt tensioners can only be trig-
gered if the belt tongue is correctly
engaged in the seat belt buckle.
The front airbags are only deployed if there is
an even higher rate of vehicle deceleration in
a longitudinal direction.
Your vehicle has adaptive, dual stage front
airbags. When the first activation threshold is
reached, the front airbag is filled with enough
propellant gas to reduce the risk of injuries.
The front airbag is only fully inflated if a sec-
ond threshold is reached within a few milli-
seconds, due to the control unit having detec-
ted further deceleration.
Criteria for triggering belt tensioners and
airbags
In the first stage of a collision, the airbag con-
trol unit evaluates the duration and direction
of vehicle acceleration or deceleration in
order to determine whether it is necessary to
trigger the belt tensioner and/or airbag.
The belt tensioner and airbag triggering
thresholds are variable and are adapted to the
rate of deceleration of the vehicle. This proc-
ess is pre-emptive in nature as the airbag
must be deployed during – and not at the end
of – the collision.
i
Airbags are not deployed in all types of
accidents. They are controlled by complex
sensor technology and evaluation logic.
This process is pre-emptive in nature as
airbag deployment must take place during
the impact and must be adapted to provide
37
Z