They tighten the seat belts against the direction in which they are pulled. Any slack in the seat belt is
retracted, which can reduce the forward movement of the vehicle occupants and their movement in
the direction of the impact. The belt tensioner works together with the airbag system. If the vehicle
rolls over, the belt tensioners will not be activated if the side airbags are not triggered.
Fine dust may be produced when belt tensioners are triggered. This is quite normal and does not
mean there is a fire in the vehicle.
Belt tension limiter
The belt tension limiter reduces the pressure exerted by the seat belt on the body in an accident.
All safety regulations must be observed when the vehicle or components of the system are
scrapped. Qualified workshops are familiar with these regulations Service and disposal of belt
tensioners
Service and disposal of belt tensioners
First read and observe the introductoryinformation and safety warnings
Seat belts may become damaged during any work on the belt tensioners or while removing or
refitting any vehicle parts in conjunction with any other repair work. This damage will not always be
noticeable. The consequence may be that the belt tensioners could function incorrectly, or not
function at all, in the event of an accident.
Regulations must be observed to ensure that the effectiveness of the belt tensioner is not reduced
and that removed parts do not cause any injuries or environmental pollution. Qualified workshops
are familiar with these regulations.
WARNING
The risk of severe or fatal injuries may be increased if the seat belts, belt retractors and belt
tensioners are not used correctly or if they are repaired by a non-professional. As a result, the belt
tensioners may not be triggered when they should be, or they may be triggered unexpectedly.
Any repairs, adjustments or removal and refitting of parts in the belt tensioners or seat belts should
always be carried out by a qualified workshop and never by yourself Accessories, modifications,
Belt tensioners and belt retractors cannot be repaired. They must be replaced.
The airbag modules and belt tensioners may contain perchlorate. Observe the applicable legislation
regarding disposal.
Proactive occupant protection system
The proactive occupant protection system is an assistance system that initiates measures to protect
vehicle occupants in dangerous situations. However, the system cannot prevent a collision.
The full range of functions of the proactive occupant protection system will be available only if the
function has been activated in the Infotainment system, no special driving profile has been selected
and there are no malfunctions Driving profile selecFunction
limitations
Basic functions
Depending on country-specific legal requirements and also on the vehicle equipment, the following
functions may be initiated, either individually or jointly, in critical situations (e.g. emergency braking
or in the case of oversteering or understeering) as of a speed of approximately 30 km/h (19 mph):
Reversible tensioning of the fastened front seat belts.
Depending on the critical driving situation, the seat belts can be tensioned separately or together.
Additional information for vehicles with an area monitoring system (Front Assist)
In vehicles fitted with the area monitoring system (Front Assist) Area monitoring system (Front
Assist)
limits. The system can trigger the proactive occupant protection system if it detects a probable
collision or initiates strong braking.
Function limitations
The proactive occupant protection system will not be available, or will be available only to a limited
extent, in the following situations:
If there is a fault in the ESC, belt tensioner Seat beltsor airbag control unit Airbag system
WARNING
The intelligent technology of the proactive occupant protection system cannot overcome the laws of
physics, and functions only within the limits of the system. Never let the extra convenience afforded
by the proactive occupant protection system tempt you into taking any risks when driving. The
system cannot prevent a collision. The system is not a substitute for the full concentration of the
driver.
Adapt your speed and distance from the vehicles ahead to suit visibility, weather, road and traffic
conditions.
The system cannot detect objects in all situations.
The proactive occupant protection system does not react to people, animals, objects crossing in
front of the vehicle, or objects which are hard to detect.
