184Driving
The selector lever lock only works if the vehicle is stationary or driving at
speeds up to 5 km/h (3 mph). At higher speeds the selector lever lock in
the N position is disengaged automatically.
The selector lever lock is not engaged if the selector lever is moved quickly
through position N (e.g. when shifting from R to D). This makes it possible,
for instance, to “rock” the vehicle backwards and forwards if it is stuck in
snow or mud. The selector lever lock engages automatically if the brake
pedal is not depressed and the lever is in position N for more than about a
second.
Interlock button
The interlock button on the selector lever handle prevents the driver from
inadvertently engaging certain gears. Press the button in to disengage the
selector lever lock. The selector lever positions in which the interlock button
has to be pressed are shown in the illustration, highlighted in colour
⇒ Fig. 149.
Safety interlock for ignition key
Once the ignition has been turned off, the key may be removed only if the
gear selector is in position P. While the key is not in the ignition, the selec-
tor lever is locked in position P.
Kick-down feature
This feature allows maximum acceleration. Vehicles with multitronic ®
gearbox
When the accelerator pedal is pressed right down past the point of resist-
ance at full throttle, the gearbox will select a lower gear ratio, depending on
road speed and engine speed. While you keep the accelerator depressed
the engine speed is automatically controlled to give your vehicle maximum
acceleration. Vehicles with tiptronic gearbox
When the accelerator pedal is pressed right down past the point of resist-
ance at full throttle, the gearbox will shift down to a lower gear, depending
on road speed and engine speed. The upshift to the next higher gear is de-
layed until the engine reaches maximum rpm.
WARNING
Please note that if the road surface is slippery or wet, the kick-down fea-
ture could cause the driving wheels to spin, which could result in skid-
ding.
Dynamic gear control programme (DCP)
The automatic gearbox is controlled electronically.
The vehicle is equipped with an electronically controlled gearbox. The gear
ratios are selected automatically according to preset gearshift programmes.
When you drive at moderate speeds the gearbox will select the most eco-
nomical shift programme. It will then change up early and delay the down-
shifts to give better fuel economy.
If you drive at higher speeds with heavy acceleration, if you open the throt-
tle quickly, or if you use the kick-down or the vehicle's maximum speed, the
gearbox will automatically select the sport programme.
The gearbox is self-adapting, and continuously selects the most suitable
shift programme. At the same time, the driver can also make the gearbox
switch to the sport programme by pressing the accelerator quickly. This
makes the gearbox shift down into a lower gear ratio, allowing a more rapid
acceleration (for instance to pass another vehicle), without having to press
the accelerator all the way down into the kick-down position. After the gear-
box has shifted back up it returns to the original programme, depending on
your style of driving.
189
Intelligent technology
WARNING
The ESC is not able to overcome the physical limits of adhesion. Even
with ESC, you should always adjust your speed to suit the road and traffic
conditions. Please bear this in mind, especially on wet or slippery road
surfaces. Do not let the extra safety features tempt you into taking any
risks when driving. Failure to do so could result in an accident.
Anti-lock brake system (ABS)
ABS prevents the wheels from locking up under braking.
The anti-lock brake system (ABS) is an important part of the vehicle's active
safety system. However, the ABS will not necessarily guarantee shorter
stopping distances in all conditions. For instance, on loose gravel or fresh
snow on top of an icy surface (conditions which anyway require extreme
care and reduced speed), the stopping distance with ABS may even be
slightly longer.
How the ABS works
The system runs an automatic self-check when the vehicle reaches a road
speed of about 6 km/h. This may be accompanied by a noise from the ABS
pump.
When one of the wheels is turning very slowly in relation to the road speed
and is close to locking up, the system will reduce the brake pressure on that
wheel. The driver is made aware of this adjustment process by a vibration of
the brake pedal and an audible noise. This is a deliberate warning to the
driver that one or more of the wheels is tending to lock up and the ABS con-
trol function has intervened. In this situation it is important to keep the
brake pedal fully depressed so the ABS can regulate the brake application,
but do not “pump” the brake pedal.
WARNING
The grip provided by ABS is still subject to the physical limits of adhe-
sion. Always bear this in mind, especially on wet or slippery roads. If you
notice that the ABS is working (to counteract locked wheels under brak-
ing), you should reduce speed immediately to suit the road and traffic
conditions. Do not let the extra safety features tempt you into taking any
risks when driving. Failure to do so could result in an accident.
Note
If a malfunction should occur in the ABS, this is indicated by a warning lamp
⇒ page 68.
Brake assist system
The brake assist system helps the driver to achieve optimum
braking effect.
The brake assist system helps to increase braking power and thus to ach-
ieve a shorter stopping distance. If the driver presses the brake pedal very
quickly, the brake assist system automatically boosts the braking force to
the maximum level, up to the point where the anti-lock brake function (ABS)
intervenes to stop the wheels from locking. You should then keep the brake
pedal pressed until the vehicle has braked to the required speed. The brake
assist system switches itself off as soon as you release the brake pedal.
The brake assist system will not be operative if there is a malfunction in the
ABS or the ESC.
Safety FirstOperating instructionsPractical TipsTechnical Specifications
190Intelligent technology
WARNING
Please remember that the accident risk always increases if you drive too
fast, especially in corners or on a slippery road, or if you follow too close
behind the vehicle in front of you. An increased accident risk cannot be
compensated even by the brake assist system. Risk of accident.
Electronic differential lock (EDL)
The electronic differential lock prevents the loss of traction
caused if one wheel starts spinning. General notes
The electronic differential lock (EDL) helps the vehicle to start moving, ac-
celerate and climb a gradient in slippery conditions where this may other-
wise be difficult or even impossible.
How it works
The EDL works automatically, without the driver's involvement. With the aid
of the ABS sensors, the system monitors the rotational speed of the drive
wheels ⇒ page 189. If a considerable difference in revs is detected (approx.
100 rpm) in the speed of the drive wheels, e.g. when only one part of the
surface supporting the wheels is slippery, the system applies the brake to
slow down the skidding wheel so that more of the power is directed to the
other wheels. The systems works up to a speed of approx. 80 km/h. The
system will make noise while it is working.
Starting the vehicle
If one wheel has less grip and starts spinning (for instance, if one of the
drive wheels is on ice), keep pressing the accelerator gradually until the ve-
hicle starts moving. Overheating of the brakes
To prevent the brake disk of the braked wheel from overheating, the EDL
cuts out automatically if subjected to excessive loads. In this case, the vehi-
cle will continue to run and will have the same running properties as those
of another without EDL.
The EDL will switch on again automatically when the brake has cooled
down.
WARNING
● When accelerating on a uniformly slippery surface (for instance all
four wheels on ice or snow), press the accelerator gradually and careful-
ly. Despite EDL, the drive wheels may otherwise start to spin. This could
impair the vehicle's stability. Risk of accident.
● Even with EDL, you should always adjust your speed to suit the road
and traffic conditions. Do not let the extra safety features tempt you into
taking any risks when driving. Failure to do so could result in an accident.
Note
If the ABS warning lamp lights up, this can also mean there is a fault in the
EDL. Take the vehicle to a specialised workshop as soon as possible.
Traction control system (ASR)
The traction control system prevents the driven wheels from
spinning when the vehicle is accelerating. General notes
The traction control system (ASR) is one of the functions incorporated in the
Electronic Stability Control (ESC)
192Intelligent technology
Brakes
General notes
New brake pads
New brake pads do not provide optimal performance during the first 200 km
(250 miles); first they must be “run in”. However, the reduced braking ca-
pacity may be compensated by pressing on the brake pedal a little harder.
Avoid overloading the brakes during run-in.
Wear
The rate of wear on the brake pads depends a great deal on how you drive
and the conditions in which the vehicle is operated. Negative factors are, for
instance, city traffic, frequent short trips or hard driving with abrupt starts
and stops.
Wet roads or road salt
In certain conditions, such as in heavy rain, or after washing the vehicle or
driving through water, the full braking effect can be delayed by moisture (or
in winter by ice) on the discs and brake pads. In this case the brakes should
be dried by pressing the brake pedal several times.
The effectiveness of the brakes can also be temporarily reduced if the vehi-
cle is driven for some distance without using the brakes when there is a lot
of salt on the road in winter. In this case, the layer of salt on the brake discs
and pads has to wear off before braking.
Corrosion
There may be a tendency for corrosion to form on the discs and dirt to build
up on the brake pads if the vehicle is used infrequently or the brakes are
not used very often.
If the brakes are not used frequently, or if rust has formed on the disks, it is
advisable to clean off the pads and disks by braking firmly a few times at a
moderately high speed ⇒
. Faults in the brake system
If the brake pedal travel should ever increase
suddenly, this may mean that
one of the two brake circuits has failed. Drive immediately to the nearest
specialised workshop and have the fault repaired. Drive there slowly and re-
member that you will have to apply more pressure on the brake pedal and
allow for longer stopping distances.
Low brake fluid level
Malfunctions can occur in the brake system if the brake fluid level is too
low. The brake fluid level is monitored electronically.
WARNING
Apply the brakes heavily to clean the brake system only in a suitable traf-
fic situation. Be sure not to inconvenience or endanger other road users.
Risk of accident.
CAUTION
● Never let the brakes “drag” by leaving your foot on the pedal when it is
not necessary to brake. This overheats the brakes, resulting in longer stop-
ping distances and greater wear.
● Before driving down a long, steep gradient, it is advisable to reduce
speed and change to a lower gear (or move the gear lever to a lower gear
position if your vehicle has an automatic gearbox). This makes use of en-
gine braking and prolongs the useful life of the brakes. If you still have to
use the brakes, it is better to brake firmly at intervals than to apply the
brakes continuously.
Note
If you wish to equip the vehicle with accessories such as a front spoiler or
wheel covers, it is important that the flow of air to the front wheels is not
obstructed, otherwise the brakes can overheat.
193
Intelligent technology
Brake servo
The brake servo assists the driver when braking
The brake servo increases the pressure you apply to the brake pedal. The
brake servo works only when the engine is running.
WARNING
Ensure the vehicle does not move while in neutral, when the engine is
stopped. Failure to do so could result in an accident.
Note
If the brake servo is not working, e.g. because the vehicle has to be towed
or because it is broken, you will have to press the brake pedal considerably
harder to make up for the lack of servo assistance.
Power steering
Power steering makes it easier to turn the steering wheel
when the engine is running. Power steering assists the driver by reducing the force needed to turn the
steering wheel.
Power steering does not work if the engine is off. In this case the steering
wheel requires much more force to turn.
If the steering is held at its turning limit when the vehicle is stationary, this
will place an excessive load on the power steering system. Turning the
steering wheel to its limit places a load on the system, which causes noise.
It will also reduce the idling speed of the engine.
CAUTION
When the engine is running, do not turn the steering wheel to its limit for
more than 15 seconds. Otherwise, there is a risk of damaging the power
steering.
Note
● If the power steering should fail at any time or the engine is switched off
(for instance when being towed), the vehicle can still be steered. However,
more effort will be required to turn the steering wheel.
● If the system is leaking or malfunctioning, please take the vehicle to a
specialised workshop as soon as possible.
● The power steering system requires a special hydraulic fluid. The fluid
reservoir is located at the front of the engine compartment on the left
⇒ page 297. The correct fluid level in the reservoir is important for the pow-
er steering to function properly. The hydraulic fluid level is checked at the
Inspection Service.
Servotronic*
The servotronic system electronically adjusts the power as-
sisted steering.
In vehicles equipped with servotronic power steering the degree of power
assistance ⇒ page 193 is adjusted
electronically according to road speed.
If a fault should occur in the servotronic system, the power steering will still
operate. The degree of power assistance will, however, no longer adapt to
different speeds. If the electronic regulating system is not working properly,
this is most noticeable when turning the steering wheel at low speeds (for
instance when parking), as more effort will be required than usual. The fault
should be corrected by a specialised workshop as soon as possible.
Safety FirstOperating instructionsPractical TipsTechnical Specifications
194Driving and the environment
Driving and the environment
Running-in Running in a new engine
The engine needs to be run in over the first 1,500 km
(1000 miles).
Up to 1000 kilometres (600 miles)
– Do not drive at speeds of more than 2/3 the maximum speed.
– Do not accelerate hard.
– Avoid high engine revolutions.
– Do not tow a trailer.
From 1000 to 1500 kilometres (600 to 900 miles)
– Speeds can be gradually increased to the maximum road speed
or maximum permissible engine speed (rpm).
During its first few hours of running, the internal friction in the engine is
greater than later on, when all the moving parts have bedded in.
For the sake of the environment
If the engine is run in gently, its life will be increased and its oil consump-
tion reduced. Braking capacity and braking distance
The braking capacity and braking distance are influenced by
driving situations and road conditions.
The efficiency of the brakes depends directly on the
brake pad wear. The
rate of wear of the brake pads depends to a great extent on the conditions
under which the vehicle is operated and the way the vehicle is driven. If you
often drive in town traffic, drive short distances or have a sporty driving
style, we recommend that you have the thickness of your brake pads
checked by a Technical Service more frequently than recommended in the
Service Plan.
If you drive with wet brakes, for example, after crossing areas of water, in
heavy rainfall or even after washing the vehicle, the effect of the brakes is
lessened as the brake discs are wet or even frozen (in winter). In this case
the brakes should be dried by pressing the brake pedal several times.
WARNING
Longer braking distances and faults in the brake system increase the risk
of accidents.
● New brake pads must be run in and do not have the correct friction
during the first 200 km (120 miles). However, the reduced braking ca-
pacity may be compensated by pressing on the brake pedal a little hard-
er. This also applies when the brake pads have to be changed further on.
● If brakes are wet or frozen, or if you are driving on roads which have
been salted, braking power may be lower than normal.
195
Driving and the environment
WARNING (Continued)
● On steep slopes, if brakes are excessively used, they will overheat.
Before driving down a long steep slope, it is advisable to reduce speed
and change down into a lower gear or range (depending on the type of
transmission). This makes use of engine braking and relieves the brakes.
● Never let the brakes “drag” by applying light pressure. Continuous
braking will cause the brakes to overheat and the braking distance will
increase. Apply and then release the brakes alternately.
● Never let the vehicle run with the engine switched off. The braking
distance is increased considerably when the brake servo is not active.
● If the brake fluid loses its viscosity and is subjected to heavy use, va-
pour bubbles can form in the brake system. This reduces the efficiency of
the brakes.
● Non-standard or damaged front spoilers could restrict the airflow to
the brakes and cause them to overheat. Before purchasing accessories
please observe the relevant instructions ⇒ page 222, Technical modifi-
cations.
● If a brake system circuit fails, the braking distance will be increased
considerably. Contact a specialised workshop immediately and avoid un-
necessary journeys.
Exhaust gas purification system Catalytic converter*
To maintain the useful life of the catalytic converter
– Use only unleaded petrol with petrol engines, as lead damages
the catalytic converter.
– Do not let the fuel get too low in the tank. –
For engine oil changes, do not replenish with too much engine
oil ⇒ page 231.
– Never tow the vehicle to start it, use jump leads if necessary
⇒ page 286.
If you notice misfiring, uneven running or loss of power when the vehicle is
moving, reduce speed immediately and have the vehicle inspected at the
nearest specialised workshop. In general, the exhaust gas warning lamp
will light up when any of the described symptoms occur ⇒ page 66. If this
happens, unburnt fuel can enter the exhaust system and escape into the en-
vironment. The catalytic converter can also be damaged by overheating.
WARNING
The catalytic converter reaches very high temperatures! Risk of fire!
● Never park where the catalytic converter could come into contact with
dry grass or flammable materials under the vehicle.
● Do not apply additional underseal or anti-corrosion coatings to the
exhaust pipes, catalytic converter or the heat shields on the exhaust sys-
tem. These materials could catch fire when the vehicle is being driven.
CAUTION
Never run the fuel tank completely dry because the irregularity of the fuel
supply may cause ignition problems. This allows unburnt fuel to enter the
exhaust system, which could cause overheating and damage the catalytic
converter.
For the sake of the environment
Even when the emission control system is working perfectly, there may be a
smell of sulphur from the exhaust gas under some conditions. This depends
on the sulphur content of the fuel used. Quite often the problem can be
solved by changing to another brand of fuel.
Safety FirstOperating instructionsPractical TipsTechnical Specifications
196Driving and the environment
Diesel engine particulate filter*
The diesel engine particulate filter eliminates soot produced
by burning diesel.
The diesel engine particulate filter eliminates most of the soot from the ex-
haust gas system. Under normal driving conditions, the filter cleans itself. If
the driving conditions do not allow the filter to clean itself (for example,
multiple short trips) the filter will be obstructed by dust and pollen and the
warning lamp for the diesel engine particulate filter will light up. This
does not represent a fault, it is a warning that indicates that the filter has
not been able to regenerate automatically and that you must carry out a
cleaning cycle, as indicated in ⇒ page 81.
WARNING
● The diesel engine particulate filter may reach extremely high temper-
atures; the vehicle should be parked so that the exhaust pipe does not
come into contact with flammable materials underneath the vehicle. Oth-
erwise there is a risk of fire.
CAUTION
● Your vehicle is not designed to use biodiesel fuel. Never, under any cir-
cumstances refuel with biodiesel. The use of biodiesel fuel could damage
the engine and the fuel system. The addition of biodiesel to diesel by the
diesel producer in accordance with standard EN 590 is authorised and will
not cause damage to the engine or the fuel system.
● Using diesel fuel with a high sulphur content may significantly reduce
the useful life of the diesel particulate filter. Your Technical Service will be
able to tell you which countries have diesel with a high sulphur content. Economical and environmentally friendly
driving
Economical and environmentally friendly driving
Fuel consumption, environmental pollution and wear to the engine, brakes
and tyres depends in large part on your driving style. By adopting an eco-
nomical driving style and anticipating the traffic situation ahead, you can
easily reduce fuel consumption by 10-15%. Some tips on how to help you
reduce pollution while saving money are listed below.
Drive anticipating the traffic situation
A vehicle uses most fuel when accelerating. When you anticipate the situa-
tion, you have to brake less often and, thus, accelerate less. If it is possible,
let the vehicle roll with a
gear engaged, for example, if you see a red light
ahead. The braking effect achieved in this way helps to reduce the wear of
brakes and tyres; emissions and fuel consumption are reduced to zero (dis-
connection due to inertia).
Change gear early to save energy
An effective way of saving fuel is to change up quickly through the gears.
Running the engine at high rpm in the lower gears uses an unnecessary
amount of fuel.
Manual gearbox: Change from first to second gear as quickly as possible.
We recommend that, whenever possible, you change to a higher gear upon
reaching 2000 rpm. Follow the “recommended gear” indication that ap-
pears on the instrument panel ⇒ page 74.
Avoid driving at high speed
We advise you not to drive at the top speed permitted by the vehicle. Fuel
consumption, exhaust emissions and noise levels all increase very rapidly
at higher speeds. Driving at moderate speeds will help to save fuel.