
Seat belts165
Using the system
Safety
Driving Tips
General Maintenance
Breakdown assistance
Technical Data
Seat beltsWhy seat belts?It is a proven fact that seat belt s offer good protection in accidents fig. 148 . Thus
wearing a seat belt is a legal requirement in most countries.
Seat belts which have been correctly fasten ed and adjusted hold the occupants of the
car in the correct seated position fig. 148 . The belts reduce the kinetic energy
(energy of motion) to a considerable exte nt. They also prevent uncontrolled move-
ments which, in turn, may well result in severe injuries.
The occupants of a vehicle who have fastened and correctly adjusted their seat belt,
profit to a major extent from the fact that the kinetic energy is optimally absorbed by
the belts. The structure of the front end of the vehicle and other passive safety meas-
ures, such as the airbag system, also cont ribute to reducing the kinetic energy. The
energy produced is thus absorbed and there is less risk of injury.
Accident statistics prove that seat belts which are fastened and properly adjusted
reduce the risk of an injury and enhance the chance of survival in a major accident
page 166.
It is important that you pay attention to safety measures, particularly when trans-
porting children in the vehicle page 180, “What you should know about trans-
porting children!”.
WARNING
Fasten your seat belt each time before setting off, also when driving in town!
This also applies to the people seated at the rear - risk of injury!
Expectant women must also always wear a seat belt. This is the only way of
ensuring optimal protection for the unborn child page 167, “Fastening
three-point seat belts”.
It is important for the belt webbing to be properly routed if the seat belts are
to offer the maximum protection. You can see a description of how safety belts
should be fitted properly on the next pages.Note
Please comply with any differing legal requirements when using the seat belts.The physical principle of a frontal collisionFig. 149 The driver is catapulted forward if not wearing a belt / The rear seat occupant is cata-
pulted forward if not wearing a beltThe physical principle of a frontal a ccident can be explained quite simply:
Motion energy, so-called kinetic energy, is produced as soon as the vehicle is moving,
both for the vehicle and its occupants. The magnitude of this kinetic energy depends
essentially on the speed at which the vehicl e is travelling and on the weight of the
Fig. 148 Driver wearing seat belt
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166
vehicle and the occupants. The greater the speed and weight increase, the greater the
amount of energy which has to be absorbed in the event of an accident.
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 165, fig. 149 - 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 165, fig. 149 - 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 167, “How are seat belts correctly
fastened?”.
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 162, “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 ke pt clean. Soiled belt webbing may
impair proper operation of the inertia reel page 211, “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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Using the system
Safety
Driving Tips
General Maintenance
Breakdown assistance
Technical Data
Driving TipsIntelligent TechnologyElectronic stability programme (ESP)*GeneralGeneral
The ESP aids you in maintaining control of your vehicle in situations in which the
vehicle is driving at its dynamic limits, such as entering a curve fast. The risk of skidding
is reduced and your vehicle thus offers greater driving stability depending on the
conditions of the road surface. The system operates at all speeds.
The following systems are integrated into the electronic stability programme:
Electronic Differential Lock (EDL),
Traction control system (TCS),
active driver-steering recommendation (DSR),
Antilock brake system (ABS),
Brake Assist,
Uphill Start Assist.
The ESP system cannot be switched off, only the TCS system can be switched off by
pressing the button fig. 170 , the warning light
lights up. Operating principle
The ESP switches on automatically when the engine is started and then conducts a
self-test. The ESP control unit processes data from the individual systems. It also proc-
esses additional measurement data which are supplied by highly sensitive sensors: the
rotational velocity of the vehicle about its ve
rtical axis, the lateral acceleration of the
vehicle, the braking pressure and the steering angle.
The direction which the driver wishes to take is determined based on the steering
angle and the speed of the vehicle and is co nstantly compared with the actual behav-
iour of the vehicle. If differences exist, such as the vehi cle beginning to skid, the ESP will
automatically brake the appropriate wheel.
The car is stabilised again by the forces wh ich take effect when the wheel is braked.
Intervention into the brake system takes place primarily on the outer front wheel of a
vehicle which tends to oversteer (tendency for the rear of the vehicle to break away)
while occurs this is on the inner rear wh eel of a vehicle which tends to understeer
(tendency to shift out of the curve). This braking control cycle is accompanied by
noises.
During an intervention of the system, the warning light
flashes in the instrument
cluster page 33.
The ESP operates in combination with the ABS page 191. If there is a fault in the ABS
system, the ESP also does not operate.
The ESP warning light lights up in the instrument cluster when there is a fault on the
ESP
page 33.WARNING
It is also not possible for the ESP to overcome the physical limits of the vehicle.
Even if a vehicle fitted with ESP you should still always adapt your style of
driving to the condition of the road surfac e and the traffic situation. This partic-
ularly applies when driving on slippery and wet roads. The increased safety
Fig. 170 ESP switch
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188
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 234, “Accesso-
ries, changes and replacement of 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 234, “Accesso-
ries, changes and replacement of parts”.
Traction control system (TCS)
The traction control system prevents the driven wheels from spinning
when accelerating.
WARNING (continued)
Fig. 171 TCS switch
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Intelligent Technology189
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 191. 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 33.
During an intervention of the system, the TCS warning light
flashes in the instru-
ment cluster page 33.
Switching off
You can switch the TCS off and on again as you wish by pressing the button
page 188, fig. 171 . The TCS warning light lights up in the instrument cluster when
the system is switched off
page 33.
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 234, “Accesso-
ries, changes and replacement of parts”.
Active driver-steering recommendation (DSR)*Vehicles with ESP and ABS ar e 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 additional function the vehicle cannot 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
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been washed in an automatic vehicle wash , since the brake discs and brake pads may
be moist or even have a coatin g of ice on them in winter. Yo u s h o u l d d r y t h e b r a k e s a s
soon as possible by applying and releasing the brakes several times.
There also may be a certain delay before the full braking efficiency is available when
driving on roads which have been treated with road salt if you have not used the brakes
for some considerable time beforehand. The layer of salt on the brake discs and brake
pads must first be rubbed off when you apply the brakes.
Corrosion
Corrosion on the brake discs and dirt on th e bake pads occur if the vehicle has been
parked for a long period an d if you do not make much use of the braking system.
We recommend cleaning the brak e discs by firmly applying the brakes at a fairly high
speed if you do not make much use of the braking system or if surface corrosion is
present .
Faults in the brake surface
If you notice that the braking distance ha s suddenly become longer and that the brake
pedal can be depressed further, it is possible that a brake circuit of the dual-circuit
brake system has failed. Drive, in such cases, to the nearest specialist garage without
delay in order to have the problem rectified. Drive at a reduced speed while on your
way to the dealer and adapt your style of driving to the higher brake pedal pressure
required.
Low brake fluid level
An insufficient level of brake fluid may result in problems in the brake system. The level
of the brake fluid is monitored electronically page 35, “Brake system ”.
WARNING
Only apply the brakes for the purpose of drying and cleaning the brake discs
if the traffic conditions permit this. Do not place any other road users in jeop-
ardy.
When retrospectively mounting a front spoiler, solid wheel hubs etc. one
must ensure that the air supply to the front wheel brakes is not reduced other-
wise the braking system could run too hot.
Allow for the fact that new brake pads do not achieve their full braking effi-
ciency until approximately 200 kilometres. New brake pads must be first “run in” before they develop their optimal fric
tion force. You can, however, compen-
sate for this slightly reduced braking fo rce by increasing the pressure on the
brake pedal. This guideline also applie s to any new brake pads installed at a
future date.
Caution
Never allow the brakes to rub by applying sl ight pressure if you do not wish to brake
the vehicle. This causes the br akes to overheat and can also result in a longer braking
distance and excessive wear.
Before negotiating a steep downhill section, please reduce your speed, shift down
into the next lower gear (manual gearbox) or select a lower driving stage (automatic
gearbox). This enables you to make full us e of the braking power of the vehicle and
reduces the strain on the brakes. Any additional braking should be done intermittently,
not continuously.Note
The brake light flashes automatically in case of an emergency braking at speeds greater
than 60 km/h or with the intervention of th e ABS, which lasts longer than 1.5 seconds.
After the speed was reduced below 10 km/h or the vehicle was stopped, the brake light
stops flashing and the hazard warning light system switches on. The hazard warning
light system is switched of f automatically after accelerating or driving off again.Brake boosterThe brake booster boosts the pressure whic h you generate with the brake pedal. The
necessary pressure is only genera ted when the engine is running.
WARNING
Never switch off the engine befo re the vehicle is stationary.
The brake booster only operates when the engine is running. Greater phys-
ical effort for braking is required when en gine is switched off. Because if you do
not stop as normal, this can cause an accident and severe injuries.WARNING (continued)
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Using the system
Safety
Driving Tips
General Maintenance
Breakdown assistance
Technical Data
Antilock brake system (ABS)ABS prevents the wheels locking when braking.General
The ABS contributes significantly to enhanc ing the active safety of your vehicle.
Compared to a vehicle not fitted with the ABS brake system, you are able to retain
optimal steering ability even during a full br ake application on a slippery road surface
because the wheels do not lock up.
In general you must not expect that the braking distance will be shorter under all
circumstances as a result of the ABS. The braking distance for example on gravel and
fresh snow, when you should anyway be driving slowly and cautiously, will be longer.
Operating principle
The brake pressure will be reduced on a wheel which is rotating at a speed which is too
low for the speed of the vehicle and tending to lock. This control cycle is noticeable
from a pulsating movement of the brake pedal which is accompanied by noises.
This is consciously intended to provide the driver with the information that the wheels
are tending to lock (ABS control range) . You must always keep the brake pedal
depressed to enable the ABS to optimally control the brake application in this braking
range. Never interrupt the application of the brakes!
WARNING
The ABS can also not overcome the physical limits of your vehicle. Please do
not forget this, particularly when driving on icy or wet road surfaces. If the ABS
is operating within the control range, adapt your speed immediately to the
conditions of the road surface and the traffic situation. The increased safety
offered by the ABS must not tempt you to take greater risks than otherwise -
risk of an accident!
The normal braking system is still fully functional if there is an ABS fault.
Visit a specialist garage as quickly as poss ible and adjust your style of driving to
take account of the ABS fault in the meantime since you will not know the extent
of the fault and in how far the braking efficiency is affected.Note
A warning light comes on if a fault occurs in the ABS system
page 34.
Changes to vehicle (e.g. on engine, on the brakes, on chassis or another combina-
tion of tyres and wheels) can in fluence the function of the ABS page 234, “Accesso-
ries, changes and replacement of parts”.
Brake Assist*During a severe brake application (e.g. if a hazard exists), the Brake Assist increases the
braking force and thus makes it possible to rapidly produce the pressure required in
the brake system.
The majority of drivers do a pply the brakes in good time in dangerous situations, but
do not depress the brake pedal with sufficient pressure. Consequently, it is not possible
for the vehicle to achieve its maximum deceleration and the vehicle covers a greater
distance than necessary.
The Brake Assist is activated by the very qu ick operation of the brake pedal. In such
cases, a much greater braking pressure exists than during a normal brake application.
This makes it possible, even with a relatively low resistance of the brake pedal, to
produce an adequate pressure in the brake system in the shortest possible time, which
is required for maximum dece leration of the vehicle. You must apply the brake pedal
firmly and hold it in this position in or der to achieve the shortest possible braking
distance.
The Brake Assist is able to help you achi eve a shorter braking distance in emergency
situations by rapidly producing the pressure required in the brake system. It fully
exploits the attributes of the ABS. After you release the brake pedal, the function of the
Brake Assist is automatically switched off and the brakes operate in the normal way.
The Brake Assist is part of the ESP system. If a fault occurs in the ESP, the Brake Assist
function is also not available. Further information on the ESP page 187.
WARNING
The Brake Assist is also not able to overcome the physical limits of your
vehicle in terms of the braking distance required.
Adapt your speed to the conditions of the road surface and to the traffic situ-
ation.
The increased safety offered by the Brake Assist must not tempt you to take
a greater safety risk than otherwise.
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Uphill Start Assist*The uphill start assist makes it easier to start off on steep hills. The system assists a start
off by holding the brake pressure produced by the brake pedal actuation for approx. 2
seconds after releasing the brake pedal. The driver can therefore move his foot from
the brake pedal to the accelerator pedal and start off on the slope, without having to
actuate the handbrake. The brake pressure drops gradually the more you operate the
accelerator pedal. If the vehicle does not start off within 2 seconds, it starts to roll back.
The uphill start assist is active as of a 5 % slope, if the driver door is closed. It is always
active on slopes when in forward or reverse start off. When driving downhill, it is
inactive.Electromechanical power steeringThe power steering enables you to steer the vehicle with le ss physical force.
With the electromechanical power steering , the steering assist is automatically
adapted to the speed and to the steering angle.
It is still possible to fully steer the vehicle if the power steering fails or if the engine is
not running (vehicle being towed in). The only difference is that greater physical effort
is required.
If there is a fault in the power steering, the warning light
or lights up in the instru-
ment cluster page 31.
WARNING
Contact your specialist garage if the power steering is defective.
Tyre pressure monitoring system*The tyre pressure monitoring system compares with the aid of the ABS sensors the
speed and also the rolling circumference of the individual wheels. If the rolling circum-
ference of a wheel is changed, the warning light
lights up in the instrument cluster
page 34 and an audible signal sounds. The rolling circumference of the tyre can
change if:
the tyre inflation pressure is too low,
the structure of the tyre is damaged,
the vehicle is loaded on one side,
the wheels of an axle are loaded heavily (e.g. when towing a trailer or when driving
uphill or downhill),
snow chains are mounted,
the temporary spare wheel is mounted,
one wheel per axle was changed.
Basic setting of the system
After changing the tyre inflation pressures, after changing one or several wheels, the
position of a wheel on the vehicle (e.g. ex changing the wheels between the axles) or
when the warning light lights up while drivin g, a basic setting of the system must be
carried out as follows.
Inflate all tyres to the specified inflation pressure page 228.
Switch on the ignition.
Fig. 172 Button for setting the tyre
inflation pressure control value
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