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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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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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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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Using the system
Safety
Driving Tips
General Maintenance
Breakdown assistance
Technical Data
Press button page 192, fig. 172 for more than 2 seconds. While pressing
the button, the warning light
lights up. At the same time the memory of the system
is erased and the new calibration is started, which is confirmed with an audible signal
and then the warning light
goes out.
If the warning light
does not go out after the basic setting, there is a fault in the
system. Have the vehicle inspected by your nearest specialist garage.
Warning light
lights up
If the tyre inflation pressure of at least one wheel is insufficiently inflated in comparison
to the stored basic value, the warning light
lights up.
Warning light
flashes
If the warning light flashes, there is a system fault. Have the vehicle inspected by your
nearest specialist garage.
WARNING
When the warning light
lights up, immediately reduce the speed and
avoid sudden steering and brake manoeuvr es. Please stop the vehicle without
delay at the nearest possible stop and in spect the tyres and their inflation pres-
sures.
The driver is responsible for the correct tyre inflation pressures. For this
reason, the tyre inflation pressu res must be checked regularly.
Under certain circumstances (e.g. sporty style of driving, wintry or unpaved
roads) the warning light
can be delayed or does not light up at all.
The tyre pressure monitoring system does not take away the responsibility
from the driver for the correct tyre inflation pressure.Note
The tyre pressure monitoring system:
does not replace the regular tyre inflatio n pressure control, because the system
cannot detect an even pressure loss;
cannot warn in case of very rapid tyre inflation pressure loss, e.g. in case of sudden
tyre damage. In this case carefully bring the vehicle to a standstill without sudden
steering movements and without sharp braking.
In order to ensure a proper functioning of the tyre inflation pressure-control
system, it is necessary to carry out the ba sic setting again every 10 000 km or 1x a
year.
Diesel particle filter* (diesel engine)In the diesel particle filter the resu lting soot particles are collected and
burnt during the combustion of diesel fuel.Code 7GG, 7MB or 7MG on the vehicle data sticker, see fig. 173 , indicates that your
vehicle is equipped with a diesel particle fi lter. The vehicle data sticker is located on
the floor of the luggage compartment and is also stated in the Service schedule.
The diesel particle filter filters the soot particles completely from the exhaust. The soot
is collected in the diesel particle filter and burnt regularly. To assist this procedure, we
recommend not to drive regu larly over short distances.
If the diesel particle filter is clogged or there is a fault, it is indicated by the warning light
.
WARNING
The diesel particle filter achieves very high temp eratures. Therefore do not
park at points where the hot filter comes into direct contact with dry grass or
other combustible materials - risk of fire!
Never use additional underbody protection or corrosion-protection agents
for the exhaust pipes, catalytic converters, diesel particle filter or heat shields.
Fig. 173 Vehicle data sticker
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Towing a trailer203
Using the system
Safety
Driving Tips
General Maintenance
Breakdown assistance
Technical Data
Headlights
Before starting off with a hitched trailer, also check the setting of the headlights. Alter
the setting as necessary with the aid of the headlight beam adjuster
page 65, “Head-
lamp range adjustment* ”.
Detachable ball head
The ball rod is detachable on vehicles which feature a factory-fitted towing device. It is
stowed together with separate fitting instru ctions in the spare wheel well in the luggage
compartment of the vehicle.
Further information on the towing device page 204.
Note
We recommend that you also have your vehicle inspected between service inter-
vals if you tow a trailer frequently.
The handbrake on the towing vehicle must be put on when coupling and decou-
pling 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 temperature gauge if the outside temperature 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 combina-
tion.
Driving speed
Do not drive faster than 80 km/hour for safety reasons. This also applies for countries
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 cond
itions, particularly near accident black
spots.
You must always reduce your speed immediat ely 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 downhill
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 engi ne speed when the outside temperature is
very high page 16, “Coolant temperature gauge”.
If the needle of the coolant temperature gauge moves into the right-hand area or even
the red area of the scale, reduce your speed immediately. Stop and switch off the
engine if the warning light
in the instrument cluster begins flashing. Wait a few
minutes and check the level of coolant in the coolant expansion bottle page 220,
“Inspecting the coolant level”.
Please refer to the following guidelines page 32, “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 of the
engine speed. One should also not drop a gear for this reason when towing a trailer as
long as the engine can manage th e slope without any drop in speed.
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204
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 and remo val of the ball head of the towing device
is supplied with the ball head
Inspect the ball head to ensure that it is prop erly locked each time before setting off.
The inspection is performed by turning th e closed locking lever downwards. If the
locking lever can only be turned around a small angle (approx. 5°), the locking mecha-
nism 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 yo u drive without towing a trailer. Inspect
whether the end cover properly seals off the mounting shaft.
Remove the ball head beforehand if you 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. 178 Detachable ball head
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