Intelligent Technology
131
Using the system
Safety
Driving Tips
General Maintenance
Breakdown assistance
Technical Data
Driving TipsIntelligent TechnologyElectronic stability programme (ESP)*GeneralGeneral The ESP aids you maintain control of your vehicle in situations in borderline driving situations such as when negotiating a curve too fast. The risk of skidding is reduced and your vehicle thus offers greater driving stability depending on the conditions of the road surface. This occurs at all speeds. The following systems are integrated into the electronic stability programme:•
Electronic Differential Lock (EDL),
•
Traction control system (TCS),
•
Antilock brake system (ABS),
•
Brake Assist.
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 processes additional measurement data which are supplied by highly sensitive sensors: the rotational velocity of the vehi
cle about its vertical axis, the lateral accel-
eration of the vehicle, the brakin
g pressure and the steering angle.
The direction which the driver wishes to ta
ke is determined based on the steering
angle and the speed of the vehicle and is constantly compared with the actual behaviour of the vehicle. If differences exis
t, such as the vehicle beginning to skid,
the ESP will automatically brake the appropriate wheel. The car is stabilised again by the forces which 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 re
ar wheel of a vehicle which tends to under-
steer (tendency to shift out of the curve). This braking control cycle is accompanied by noises. The ESP operates in combination with the ABS
⇒page 135, “Antilock brake system
(ABS)*”. If there is a fault in the ABS system, the ESP also does not operate. The ESP warning light
⇒page 33 lights up in the instrument cluster when there is a
fault on the ESP. Switching off You can switch the ESP off and on again
as you wish, by pressing the button
⇒ fig. 139
. The ESP warning light
⇒page 33 lights up in the instrument cluster
when the ESP is switched off. The ESP 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:
Fig. 139 ESP switch
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Intelligent Technology
132
•
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 ESP again.
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 surface and the traffic situation.
This particularly applies when driving on slippery and wet roads. The increased safety offered must not tempt you to take greater risks than other- wise - risk of an accident!
Note
•
All four wheels must be fitted with the same tyres in order to achieve problem-
free operation of the ESP. Differing rolling
circumferences of the tyres can lead to an
undesirable reduction in the engine output.•
Changes to vehicle (e.g. on engine, on the brakes, on chassis or another combi-
nation of tyres and wheels) can influence the function of the ESP
⇒page 179,
“Accessories, changes and replacement of parts”.Electronic Differential Lock (EDL)* The electronic differential lock pr
events an individual wheel from
slipping.Vehicles fitted with ABS*
can be equipped with electron
ic 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 conditio
ns of the road surface are unfavourable.
Operating principle The EDL is activated automatically, 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 greater driving force to the other driven wheel. This control proces
s is also accompanied by noises.
Overheating of the brakes The EDL switches off
automatically 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 driv
en 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 slip-
pery road surfaces, such as ice and sn
ow. The 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 warning light comes on, this ma
y 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 combi-
nation of tyres and wheels) can in
fluence the function of the EDL
⇒page 179,
“Accessories, changes and
replacement of parts”.
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Intelligent Technology
133
Using the system
Safety
Driving Tips
General Maintenance
Breakdown assistance
Technical Data
Traction control system (TCS) The traction control system prevents
the driven wheels from spinning
when accelerating.General The TCS makes it much easier, and sometimes at all possible, to start off, accelerate and climb a steep hill when the conditio
ns 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 automatically adapted by redu
cing the engine speed. Th
is occurs at all speeds.
The TCS operates in combination with the ABS
⇒page 135, “Antilock brake system
(ABS)*”. The TCS will not function if a fault exists in the ABS system. The TCS warning light
⇒page 33 lights up in the instrument cluster when there is a
fault on the TCS. Switching off You can switch the TCS off and on again
as you wish by pressing the button
⇒ fig. 140
. The TCS warning light
⇒page 33 lights up in the instrument cluster
when the TCS is switched off.
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 undesirable reduction in the engine output.•
Changes to vehicle (e.g. on engine, on
the brakes, on chassis or another combi-
nation of tyres and wheels) can in
fluence the function of the TCS
⇒page 179,
“Accessories, changes and replacement of parts”.BrakesWhat has a negative effect on braking efficiency?Wear-and-tear Wear-and-tear to the brake pads 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 neces- sary to have the thickness of the brake
pads inspected at a specialist garage
between the service inspections.
Fig. 140 TCS switch
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Intelligent Technology
134
Wet roads or road salt There may be a certain delay before the br
akes take full effect under certain condi-
tions 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 be moist or even have a
coating of ice on them in winter. You
should dry the brakes as soon as possib
le 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 wi
th road salt if yo
u have not used the
brakes for some considerable time beforeha
nd. The layer of salt on the brake discs
and brake pads must first be rubb
ed 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 and if you do
not make much use of the braking system.
We recommend cleaning the brake 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 corro-sion is present
⇒
.
Faults in the brake surface If you notice that the braking distance has 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 34, “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 jeopardy.
•
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 otherwise the braking sy
stem could run too hot.
•
Allow for the fact that new brake pads
do not achieve th
eir full braking
efficiency until approximately 200 kilo
metres. New brake pads must be first
“run in” before they develop their optimal friction force. You can, however, compensate for this slightly reduced
braking force by increasing the pres-
sure on the brake pedal. This guidelin
e also applies to any new brake pads
installed at a future date.
Caution
•
Never allow the brakes to ru
b by applying slig
ht pressure if you do not wish to
brake the vehicle. This causes the brakes to overheat and can also result in a longer braking distance and excessive wear.•
Before negotiating a steep downhill section, reduce your speed, shift down into
the next lower gear. This enables you to make full use of the braking power of the vehicle and reduces the strain on the brakes
. Any additional braking should be done
intermittently, not continuously.Brake boosterThe brake booster boosts the pressure which you generate with the brake pedal. The necessary pressure is only gene
rated 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
physical effort for braking is required
when engine is swit
ched off. Because
if you do not stop as normal, this can cause an accident and severe injuries.
WARNING (continued)
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Intelligent Technology
135
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 significan
tly to enhancing 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 fu
ll brake application on a slippery road
surface because the wheels do not lock up. You must not expect, however, that the br
aking distance will be shorter under all
circumstances as a result of the ABS. Th
e 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 tend
ing to lock. This control cycle is notice-
able 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 optima
lly control the brake application in this
braking range. Never interrupt the application of the brakes!
WARNING
•
The ABS can also not overcome the physic
al limits of your
vehicle. Please
do not forget this, particularly when driv
ing on icy or wet road surfaces. If the
ABS is operating within the control ra
nge, adapt your speed immediately to
the conditions of the road surface an
d 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 possible and adju
st 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 32.
•
Changes to vehicle (e.g. on engine, on
the brakes, on chassis or another combi-
nation of tyres and wheels) can in
fluence the function of the ABS
⇒page 179,
“Accessories, 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 apply the brakes in good time in dangerous situations, but do not depress the brake pedal with suff
icient 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 quick operation of the brake pedal. In such cases, a much greater braking pressure ex
ists than during a
normal brake applica-
tion. 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 decelerati
on of the vehicle. You must apply the
brake pedal firmly and
hold it in this position in order 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 yo
u release the brake peda
l, the function of
the Brake Assist is automatically switched off and the brakes operate in the normal way.
WARNING
•
The Brake Assist is also not able to overcome the physical limits of your
vehicle in terms of the br
aking distance required.
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Towing a trailer
145
Using the system
Safety
Driving Tips
General Maintenance
Breakdown assistance
Technical Data
should be attached to folding arms. Adjust
the mirrors so that they provide you with
an adequate field of view to the rear. Headlights Before starting off with a hitched trailer, also check the setting of the headlights. Alter the setting as necessary with th
e aid of the headlight beam adjuster
⇒ page 51. Detachable ball head The ball rod is detachable on vehicles which feature a factory-fitted towing device. It is stowed together with separate fitting instructions in the spare wheel well in the luggage compartment of the vehicle. Further information on the towing device
⇒page 146.
Note
•
We recommend that you also have yo
ur vehicle inspected between service
intervals if you tow a trailer frequently.•
The handbrake on the towing vehicle
must be put on when coupling and
decoupling the trailer.Driving Tips Particular caution is required when towing a trailer.– Do not, as far as possible, drive
with your vehicle unladen and the
trailer laden.
– Do not make full use of the legal maximum speeds. This applies in
particular to downhill sections.
– Apply the brakes in good time.– Keep a check on the coolant temper
ature gauge if the outside temper-
ature is high.
Distribution of weight The distribution of the weight is very poor
if your vehicle is
unladen and the trailer
is laden. Maintain a particularly low speed if you cannot avoid driving with this combination. Driving speed Do not drive faster than 80 km/hour for safety reasons. This also applies for coun- tries in which higher speeds are allowed. The fact that the driving stability of the vehicle + trailer combination reduces with increasing speed means that the legally allowed speed should not be used when there are unfavourable road, weather or wind
conditions, particul
arly near accident
black spots. You must always reduce your speed immedi
ately as soon as you detect even just
the
slightest swaying
of the trailer. On no account attempt to stop the trailer from
“swaying” by
accelerating.
Apply the brakes in good time! If the trailer is fitted with a
trailer brake
, apply the
brakes gently at first and then brake firmly
. This will avoid brake jolts resulting from
the trailer wheels locking. Shift down gears
in good time before negotiating a down-
hill section to allow the engine to also act as a brake. Engine overheating Please keep a check on the coolant temperature gauge if you have to negotiate a lengthy slope in a low gear at a high engine speed when the outside temperature is very high
⇒page 16.
If the needle of the coolant temperature gauge moves into the right-hand area or even the red area of the scale, reduce yo
ur speed immediately. Stop and switch off
the engine if the warning light
in the instrument cluste
r begins flashing. Wait a
few minutes and check the level of coolant in the coolant expansion bottle ⇒ page 165, “Inspecting the coolant level”. Please refer to the following guidelines
⇒page 30, “Coolant temperature/ Coolant
quantity
”.
The coolant temperature can be reduced by switching on the heating.Any increase in the cooling effect of the coolant fan through shifting down a gear and increasing the engine speed is not possible since the fan speed is independent
s2g8.b.book Page 145 Tuesday, April 7, 2009 8:53 AM
Towing a trailer
146
of the engine speed. One should also not
drop a gear for this reason when towing
a trailer as long as the en
gine can manage the slope
without any drop in speed.
Detachable towing device*The detachable ball head of the towing device
is stowed in a box for the car tool kit
in the spare wheel well in the luggage compartment. An instruction for correct installation an
d removal of the ball head of the towing
device is supplied
with the ball head
Inspect the ball head to ensure that it is pr
operly locked each time before setting off.
The inspection is performed by turning the closed locking lever downwards. If the locking lever can only be turned around a small angle (approx. 5°), the locking mechanism is O.K. After the inspection pull
the locking lever back again to its stop.
The towing device must not be used, if it does not wish to close or the locking lever turns slightly in the closed position.
WARNING
Do not use any aids or tools for installing or removing the ball head. This might result in damage to the locking mechanism to the extent that the safety of the towing device is no longer assured - risk of an accident.
Note
•
Do not carry out any modifications or repairs to the ball head or to any other
components on the towing device.•
Contact a specialist garage if you en
counter any problems using the device.
•
Never unlock the ball head with a trailer coupled to it.
•
You should take off the ball head if you drive without towing a trailer. Inspect
whether the end cover properly seals off the mounting shaft.•
Remove the ball head beforehand if yo
u wish to clean your vehicle using a
steam jet. Ensure that the end cover properly seals the mounting shaft.•
It is recommended to wear gloves
when installing and removing.
Fig. 144 Detachable ball head
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Taking care of your vehicle and cleaning the vehicle
148
Automatic vehicle wash systemsThe paintwork of the vehicle is sufficiently resistant that the vehicle can be washed normally in automatic vehicle wash plants without any problem. The actual stress to which the paintwork is subjected, however, depends greatly on the design of the vehicle wash system, the filtering of the water and the type of washing and care products used. If the paintwork of your
vehicle appears mat after being washed or
even has scratches, point this out to the operator of the vehicle wash plant. Use a different vehicle wash plant, if necessary. There are no particular points to note be
fore washing your vehicle in such a plant
other than the usual precautionary measur
es (closing windows and sliding/tilting
roof, moving any factory-fitted aerials down flat against the bodywork, etc.). If you have any particular atta
ch e d p a r t s f i t te d t o y o u r c a r - s u ch a s s p o i l e r, ro o f ra ck
system, two-way radio aerial - it is best to
first of all consult the operator of the car
wash plant. It is important to degrease the lips of
the windscreen wiper rubbers after passing
through the automatic vehicle wash system.
Caution
Do not screw the swivelling down roof aeri
al tight before washing the vehicle in an
automatic vehicle wash sy
stem - risk of damage!
Washing vehicle by handIt is important to first soften the dirt with
plenty of water and
rinse it off as thor-
oughly as possible before wa
shing your vehi
cle by hand.
One should then clean the vehicle using a soft
washing sponge
, washing glove
or
a washing brush
and only slight pressure. Work
from the top to the bottom -
beginning with the roof. Only place slight
pressure on the vehicle paintwork during
cleaning Only use a
car shampoo
for stubborn dirt.
Wash out the sponge or washing glove thoroughly at short intervals.Clean wheels, door sills and similar parts
last. Use a second sponge for such areas.
Rinse off the vehicle well after giving it a
wash and dry it off using a chamois leather.
WARNING
•
The ignition should always be switched off when you wash your vehicle -
risk of accident!•
Protect your hands and arms from sharp-edged metal parts when you
are cleaning the underfloor, the inside
of the wheel housings or the wheel
trims - risk of cuts.
Caution
•
Do not wash your vehicle in bright
sunlight - risk of paint damage.
•
Ensure that the jet of water is not aimed di
rectly at the locking cylinders or at the
door and panel joints if you spray your vehicle in winter down with a hose - risk of freezing.•
Do not use any insect sponges, rough ki
tchen sponges or simi
lar cleaning prod-
ucts - risk of damage to the surface of paintwork.
For the sake of the environment
Only wash your vehicle at washing bays specifically reserved for this purpose. This ensures that no water which may be cont
aminated by oil flow
s into the sewage
system. It is not even permitted to wash your vehicle in certain areas except at such specific washing bays.Washing with a high-pressure cleanerWhen you wash your vehicle with a high-pre
ssure cleaner, it is
essential to comply
with the instructions for use of the cleaning equipment. This applies in particular to the
pressure
used and to the
spraying distance
. Maintain a sufficiently large
distance to soft materials such as
rubber hoses or insulation material.
On no account use
circular spray nozzles
or so-called
dirt cutters
!
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