Seat belts
90
The speed of the vehicle is, nevertheless, the most important factor. Doubling the
speed of the vehicle from 25 km/h up to 50 km/hour increases the kinetic energy four
times.
The common opinion that it is possible to su pport your body in a minor accident with
your hands, is incorrect. Even in a collision at only a low speed, the forces acting on the
body are such that it is no longer possible to support your body.
Even if you only drive at a speed within the range from 30 km/hour to 50 km/hour, the
forces which are produced on your body in the event of an accident can easily exceed
10.000 N (Newton). This equals a weight of one tonne (1 000 kg).
In the event of a frontal collision, occupants of the vehicle not wearing a seat belt, are
thrown forward and strike in an uncontrolled way parts of the interior of the vehicle,
such as steering wheel, dash panel, windscreen, page 89, fig. 91 - left. The occu-
pants of a vehicle who have not fastened their seat belts may even be thrown out of
the vehicle. This can result in fatal injuries.
It is also important that rear seat occupants fasten their seat belts as they will otherwise
be thrown through the vehicle in an uncontr olled manner in the event of an accident
A rear seat passenger who has not fastened the s eat bel t i s a dang er not o nl y to hims elf
but also for those seated at the front page 89, fig. 91 - right.Important safety information regarding the use of seat beltsThe correct use of the seat belts cons iderably reduces the risk of injury!
WARNING
The belt webbing must not be jammed in-between at any point or twisted,
or chafe against any sharp edges.
It is important that the belt webbing is properly routed if the seat belts are
to offer their maximum protection page 91.
No two persons (also not children) should ever use a single seat belt
together.
The maximum protection which seat belts can offer is only achieved if you
are correctly seated page 86, “Correct seated position”.
The belt webbing must not run across solid or fragile objects (e.g. specta-
cles, ball-point pens, keys etc.) as this may be a cause of injuries.
Bulky, loose clothing (e.g. a winter coat over a jacket) does not allow you to
be correctly seated and impairs proper operation of the seat belts.
It is prohibited to use clamps or other objects to adjust seat belts (e.g. for
shortening the belts for smaller persons).
The lock tongue should only be inserted into the lock which is the correct
one for your seat. Wrong use of the safety belt will reduce its capacity to protect
and the risk of injury increases.
The seat backrests of the front seats must not be tilted too far to the rear
otherwise the seatbelts can lose their effectiveness.
The belt webbing must always be kept clean. A soiled belt webbing may
impair proper operation of the inertia reel page 135, “Seat belts”.
The slot of the belt tongue must not be blocked by paper or similar objects
otherwise the belt tongue will not lock in place properly.
Inspect the seat belts regula rly to ensure they are in good condition. If you
find seat belts which have damage to the seat belt webbing, seat belt connec-
tions, to the inertia reels or to the lock, the relevant safety belt must be replaced
by a specialist garage.
The seat belts must not be removed or changed in any way. Do not make an
attempt to repair the seat belts yourself.
Damaged seat belts which have been subjected to stress in an accident and
were therefore stretched, must be replaced - this is best done by a specialist
garage. The anchorage points of the belts must also be inspected. The
anchorage points for the belts should also be checked.
In certain countries it is possible to use seat belts which differ in terms of
their operation from the seat belts which are described on the pages which
follow.WARNING (continued)
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Intelligent Technology
112
offered must not tempt you to take greater risks than otherwise - risk of an acci-
dent!
Note
All four wheels must be fitted with the same tyres in order to achieve problem-free
operation of the ESP. Differing rolling circum ferences of the tyres can lead to an unde-
sirable reduction in the engine output.
Changes to vehicle (e.g. on engine, on th e brakes, on chassis or another combina-
tion of tyres and wheels) can influence the function of the ESP page 157, “Accesso-
ries, changing and replacing parts”.
Electronic Differential Lock (EDL)*
The electronic differential lock prev ents an individual wheel from slip-
ping.Models fitted with ESP ar e equipped with electronic differential lock (EDL).
General
The EDL makes it much easier, and sometimes at all possible, to start off, accelerate
and climb a steep hill when the conditions of the road surface are unfavourable.
Operating principle
The EDL is activated automaticall y, that is without any action on the part of the driver.
It monitors the speeds of the driven wheels with the aid of the ABS sensors. Should
only one drive wheel begin spinning on a slippery surface there will be an appreciable
difference in the speed of the driven wheels. The EDL function brakes the slipping
wheel and the differential transmits a greate r driving force to the other driven wheel.
This control process is also accompanied by noises.
Overheating of the brakes
The EDL switches off automatica lly if unusually severe stresses exist in order to avoid
excessive heat generation in the disc brake on the wheel which is being braked. The
vehicle can continue to be driven and has the same characteristics as a vehicle not
fitted with EDL. The EDL switches on again automatically
as soon as the brake has cooled down.
WARNING
Carefully depress the accelerator when accelerating on uniformly slippery
road surfaces, such as ice and snow. Th e driven wheels might still spin despite
the EDL and affect the stability of the vehicle - risk of an accident!
You should always adapt your style of driving to the condition of road
surface and to the traffic situation even when your vehicle is fitted with EDL.
The increased safety offered must not tempt you to take greater risks than
otherwise - risk of an accident!Note
If the ABS or ESP warning light comes on, this may also indicate a fault in the EDL.
Please have the vehicle inspected as soon as possible by a specialist garage.
Changes to vehicle (e.g. on engine, on the brakes, on chassis or another combina-
tion of tyres and wheels) can influence the function of the EDL page 157, “Accesso-
ries, changing and replacing parts”.
Traction control system (TCS)
The traction control system prevents the driven wheels from spinning
when accelerating.
WARNING (continued)
Fig. 112 TCS switch
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Intelligent Technology113
Using the system
Safety
Driving Tips
General Maintenance
Breakdown assistance
Technical Data
General
The TCS makes it much easier, and sometimes at
all possible, to start off, accelerate and
climb a steep hill when th e conditions of the road surface are unfavourable.
Operating principle
The TCS switches on automatically when th e engine is started and then conducts a
self-test. The system monitors the speeds of the driven wheels with the aid of the ABS
sensors. If the wheels are spinning, the force transmitted to the road surface is auto-
matically adapted by reducing the engine speed. The system operates at all speeds.
The TCS operates in combination with the ABS page 115, “Antilock brake system
(ABS)”. The TCS will not function if a fault exists in the ABS system.
The TCS warning light lights up in the instru ment cluster when there is a fault on the
TCS
page 26.
During an intervention of the system, the TCS warning light
flashes in the instru-
ment cluster page 26.
Switching off
You can switch the TCS off and on again as you wish by pressing the button
page 112, fig. 112 . The TCS warning light lights up in the instrument cluster when
the TCS is switched off
page 26.
The TCS should normally always be switched on. It may be good practice in certain
exceptional cases, such as when you wish to have wheel slip, to switch off the system.
Examples:
when driving with snow chains
when driving in deep snow or on a loose surface
when it is necessary to rock a vehicle when it has become stuck.
then you should switch on the TCS again.
WARNING
You should always adjust your style of driving to the conditions of the road
surface and the traffic situation. The increased safety offered must not tempt
you to take greater risks than otherwise - risk of an accident!
Note
All four wheels must be fitted with the same tyres in order to achieve problem-free
operation of the TCS. Differing rolling circumferences of the tyres can lead to an unde-
sirable reduction in the engine output.
Changes to vehicle (e.g. on engine, on the brakes, on chassis or another combina-
tion of tyres and wheels) can influence the function of the TCS page 157, “Accesso-
ries, changing and replacing parts”.
Active driver-steering recommendation (DSR)*Vehicles with ESP are equipped with active driver-steering recommendation (DSR).
This function indicates to the driver in crit ical situations a steering recommendation in
order to stabilise the vehicle. The active driver-steering recommendation is activated,
for example, on the right and left vehicle si de when braking sharply on different road
surfaces.
WARNING
Even with this function the vehicle cann ot steer itself! The driver is furthermore
responsible for the steering of the vehicle!BrakesWhat has a negative effect on braking efficiency?Wear-and-tear
Wear-and-tear to the brake pa ds is greatly dependent on the operating conditions of
the vehicle and your style of driving. Particularly if you drive a great deal in towns and
over short distances or if you adopt a sporty style of driving, it may be necessary to
have the thickness of the brake pads insp ected at a specialist garage between the
service inspections.
Wet roads or road salt
There may be a certain delay before the brakes take full effect un der certain conditions
such as when driving through water, during heavy rain showers or after the vehicle has
been washed in an automatic vehicle wash , since the brake discs and brake pads may
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Wheels and Tyres155
Using the system
Safety
Driving Tips
General Maintenance
Breakdown assistance
Technical Data
Winter tyresThe handling of your vehicle will be signif icantly improved when driving on wintry
roads if you fit winter tyres. Summer tyres do not offer the same grip on ice, snow and
at temperatures below 7 °C because of thei r construction (width, rubber blend, tread
pattern). This particularly applies to vehicles which are equipped with low-profile
tyres or high-speed tyres (code index H or V on wall of tyre).
Winter tyres must be mounted on all four wheels to obtain the best handling charac-
teristics.
You must only fit those types of winter tyre which are approved for your vehicle. The
permissible sizes of winter tyres are stated in your vehicle documents. Approvals may
differ because of na tional legislation.
Please remember that the tyres should be inflated to 20 kPa (0.2 bar) more than is the
case for summer tyres page 151.
Winter tyres no longer offer the same winter performance once the tyre tread has
worn down to a depth of about 4 mm.
Ageing also causes winter tyres to lose most of their winter performance properties -
even in cases where the remaining tread depth is still clearly more than 4 mm.
Speed restrictions apply to winter tyres as well as to summer tyres page 153,
.
You can fit winter tyres of a lower speed catego ry to your vehicle provided that you also
do not drive faster than the permissible maximum speed for such tyres, even if the
possible maximum speed of your vehicle is higher. The corresponding tyre category
can damage the tyres when exceeding the permissible maximum speed.
Please pay attention to the notes if you decide to fit winter tyres page 151.
You can also fit so-called “all-year tyres” instead of winter tyres.
Please contact your specialist garage if there are any points which are not clear who will
be able to provide you with information regarding the maximum speed for your tyres.
WARNING
You must on no account drive your car at more than the permissible maximum
speed for your winter tyres - risk of an accident resulting from tyre damage and
loss of control over your car.
For the sake of the environment
Fit your summer tyres on again in good time since summer tyres offer you better grip
and handling on roads which are free of snow and ice as well as are temperatures
below 7 °C - the braking distance is shorter, there is less tyre noise, tyre wear is reduced
and fuel consumption is reduced.
Note
Please observe the various differing legal requirements regarding tyres.Unidirectional tyres*The direction of rotation of the tyres is marked by arrows on the wall of the tyre. This
indicates the direction of rotation of the tyre, and it is essential that the tyres are fitted
on to run in this direction. Only then are the tyres able to provide the optimal proper-
ties in terms of grip, low nois e, wear-and-tear and aquaplaning.
Should it be necessary to fit on a spare wheel in exceptional cases with a tyre not dedi-
cated to the running direction or in oppo site running direction, please adopt a
cautious style of driving as the tyre is no longer able to provide optimal grip and
handling in such a situation. This particular ly important on wet roads. Please refer to
the notes page 160, “Spare wheel*”.
You should have the defective tyre replaced as soon as possible and restore the correct
direction of rotation on all tyresSnow chainsSnow chains must only be mounted on the front wheels.
When driving on wintry roads, snow chains improve not only traction, but also the
braking performance.
For technical reasons, it is only permissi ble to fit snow chains with the following
wheel/tyre combinations:
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