Intelligent Technology155
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 vehicle about its vertical axis, the lateral accel-
eration 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 constantly compared with the actual
behaviour of the vehicle. If differences exist, 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 rear 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 159, “Antilock brake system
(ABS)*”. 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 32.
Switching off
You can switch the ESP off and on again as you wish, by pressing the button
⇒fig. 170. The ESP warning light lights up in the instrument cluster when the ESP is
switched off
⇒page 32.
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. 170 ESP switch
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Intelligent Technology 156•
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 204,
“Accessories, changes and replacement of parts”.
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 conditions of the road surface are unfavourable.
Operating principle
The TCS switches on automatically when the 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 reducing the engine speed. This occurs at all speeds.
The TCS operates in combination with the ABS ⇒page 159, “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 instrument cluster when there is a fault on the
TCS
⇒page 31.
Switching off
You can switch the TCS off and on again as you wish by pressing the button
⇒fig. 171. The TCS warning light lights up in the instrument cluster when the TCS is
switched off
⇒page 31.
Fig. 171 TCS switch
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Intelligent Technology157
Using the system
Safety
Driving Tips
General Maintenance
Breakdown assistance
Technical Data 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 influence the function of the TCS ⇒page 204,
“Accessories, changes and replacement of parts”.
Electronic Differential Lock (EDL)*
The electronic differential lock prevents an individual wheel from
slipping.Models fitted with ESP are 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 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 process 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 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 slip-
pery road surfaces, such as ice and snow. 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 or TCS 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 combi-
nation of tyres and wheels) can influence the function of the EDL ⇒page 204,
“Accessories, changes and replacement of parts”.
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Intelligent Technology 158BrakesWhat 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.
Wet roads or road salt
There may be a certain delay before the brakes 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 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 the 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 33, “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 system could run too hot.
•
Allow for the fact that new brake pads do not achieve their full braking
efficiency until approximately 200 kilometres. 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 guideline also applies to any new brake pads
installed at a future date.Caution
•
Never allow the brakes to rub by applying slight 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, please reduce your speed and shift
down into the next lower gear (manual gearbox) or select a lower driving stage
(automatic gearbox). 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 generated when the engine is running.
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Intelligent Technology159
Using the system
Safety
Driving Tips
General Maintenance
Breakdown assistance
Technical Data
WARNING
•
Never switch off the engine before the vehicle is stationary.
•
The brake booster only operates when the engine is running. Greater
physical effort for braking is required when engine is switched off. Because
if you do not stop as normal, this can cause an accident and severe injuries.
Antilock brake system (ABS)*ABS prevents the wheels locking when braking.General
The ABS contributes significantly 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 full brake application on a slippery road
surface because the wheels do not lock up.
You must not expect, however, 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
As soon as the vehicle speed has increased to about 20 km/hour an automatic test
procedure is conducted during which you will be able to hear a pumping noise for
about 1 second.
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 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 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 possible 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 32.
•
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 ABS ⇒page 204,
“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 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 quick operation of the brake pedal. In such
cases, a much greater braking pressure exists 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 deceleration of the vehicle. You must apply the
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Intelligent Technology 160brake 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 achieve 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 155.
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
situation.
•
The increased safety offered by the Brake Assist must not tempt you to
take a greater safety risk than otherwise.
Electrohydraulic power steeringThe power steering enables you to steer the vehicle with less physical force.
The steering characteristics can be changed by a specialist garage.
You will place great stresses on the power steering system if the steering is turned
to full lock when the vehicle is stationary. Turning the steering to full lock in such a
situation will be accompanied by noises.
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.
It is possible that the hydraulic pump of the power steering will not run due to the
low vehicle network voltage if the battery has gone flat and the engine must started
with the help off jump leads. This condition will be indicated by lighting up of the
warning light.The power steering operates again if the battery is charged to a specific range when
engine is running. It also operates again, if the engine can be started with its own
battery.
If there is a fault in the power steering, the warning light lights up in the instrument
cluster
⇒page 26.
Caution
Do not leave the steering at full lock for more than 15 seconds when the engine is
running - risk of damaging the power steering!
Note
Have the steering inspected as soon as possible by a specialist garage if there is a
leak or fault in the system.Tyre inflation pressure-control system*The tyre inflation pressure-control system compares with the aid of the ABS sensors
the speed and also the rolling circumference of the individual wheels. If the tyre
inflation pressure is significantly changed and thus the rolling circumference of a
wheel, the warning light
lights up in the instrument cluster ⇒page 32. The tyre
inflation pressure-control system functions late or too sensitively if:
Fig. 172 Button for setting
the tyre inflation pressure
control value
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Intelligent Technology 162Diesel particle filter* (diesel engine)In the diesel particle filter the resulting 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, indi-
cates that your vehicle is equipped with a diesel particle filter. 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 proce-
dure, we recommend not to drive regularly over short distances.
If the diesel particle filter is clogged or there is a fault, it is indicated by the warning
light
⇒page 34, “Diesel particle filter* (diesel engine)”.WARNING
•
The diesel particle filter achieves very high temperatures. 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, heat shields or diesel particle filter. When the engine reaches its operating temperature, these
substances might ignite - risk of fire!
Note
•
When using diesel fuel with high sulphur content the life of the diesel particle
filter is clearly reduced. A specialist garage will be able to tell you which countries
use only diesel fuel with high sulphur content.
Fig. 173 Vehicle data sticker
WARNING (continued)
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Driving and the Environment163
Using the system
Safety
Driving Tips
General Maintenance
Breakdown assistance
Technical Data
Driving and the EnvironmentThe first 1 500 kilometres and then afterwardsA new engine
The engine has to be run in during the first 1 500 kilometres.Up to 1 000 kilometres
– Do not drive faster than 3/4 of the maximum speed of the gear in use,
that is 3/4 of the maximum permissible engine speed.
– Do not use full throttle.
– Avoid high engine revolutions.
– Do not tow a trailer.
From 1 000 up to 1 500 kilometres
– Increase the power output of the engine gradually up to the full
speed of the gear engaged, that is up to the maximum permissible
engine revolutions.During the first operating hours the engine has higher internal friction than later
until all of the moving parts have harmonized. The driving style which you adopt
during the first approx.1 500 kilometres plays a decisive part in the success of
running in your vehicle.
You should not drive at unnecessarily high engine revolutions even after the
running-in period is complete. The maximum permissible engine speed is marked
by the beginning of the red zone on the scale of the revolutions counter. Shift up
into the next higher gear on a vehicle fitted with manual gearbox before the red
zone is reached. During acceleration (depressing the accelerator) exceptionally
high engine speeds are automatically reduced, yet the engine is not protected
against too high engine speeds which are caused by incorrectly shifting down the
gears resulting in a sudden increase of the engine speeds above the permitted
maximum revolutions which can lead to engine damage.For a vehicle fitted with a manual gearbox the converse situation also applies: Do
not drive at engine revolutions which are too low. Shift down as soon as the engine
is no longer running smoothly.
Caution
All the speed and engine revolution figures apply only when the engine is at its
normal operating temperature. Never rev up an engine which is cold, neither when
the vehicle is stationary nor when driving in individual gears.
For the sake of the environment
Not driving at unnecessarily high engine revolutions and shifting to a higher gear as
early as possible are ways to minimise fuel consumption, operating noise levels as
well as protects the environment and contributes to a longer life and reliability of
the engine.New tyresNew tyres have to be “run in” since they do not offer optimal grip at first. You should
take account of this fact for the first 500 kilometres and drive particularly carefully.New brake padsAllow for the fact that new brake pads do not achieve their full braking efficiency
until approximately 200 kilometres. 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 pressure on the brake pedal.
This guideline also applies to any new brake pads installed at a future date.
During the running-in period, you should avoid excessive stresses on the brakes.
This includes, for example, violent braking, particularly from very high speeds, and
also when crossing mountain passes.
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