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Practical Tips Intelligent technology
Brakes Brake servo
The brake servo increases the pressure you apply to the brake pedal. It
works only when the engine is running .
If the brake servo is not functioning due to a malfunction, or if the vehicle
has to be towed, you will have to press the brake pedal considerably harder
to make up for the lack of servo assistance.
WARNING
The braking distance can also be affected by external factors.
● Never let the vehicle coast with the engine switched off. Failure to do
so could result in an accident. The braking distance is increased consid-
erably when the brake servo is not active.
● If the brake servo is not working, for example when the vehicle is be-
ing towed, you will have to press the brake pedal considerably harder
than normal.
Hydraulic Brake Assist (HBA)*
The Hydraulic Brake Assist function (HBA) is only included in
vehicles with ESP.
In an emergency, most drivers brake in time, but not with maximum force.
This results in unnecessarily long braking distances.
This is when the brake assist system comes into action. When pressing the
brake pedal rapidly, the assistant interprets it as an emergency. It then very
quickly builds up the full brake pressure so that the ABS can be activated
more quickly and efficiently, thus reducing the braking distance.
Do not reduce the pressure on the brake pedal. The brake assist system
switches off automatically as soon as you release the brake.
Automatic hazard warning lights activation
The brake lights flash automatically to indicate that the vehicle is braking
suddenly or in an emergency situation. If the emergency braking continues
until the vehicle comes to a standstill, the hazard warning lights will then
come on and the brake lights will remain on permanently from that moment.
The warning lights will automatically switch off when the vehicle begins to
move again or when the "warning" light button is pressed.
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WARNING
● The risk of accident is higher if you drive too fast, if you do not keep
your distance to the vehicle in front, and when the road surface is slip-
pery or wet. The increased accident risk cannot be reduced by the brake
assist system.
● The brake assist system cannot defy the laws of physics. Slippery
and wet roads are dangerous even with the brake assist system! There-
fore, it is essential that you 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.
Anti-lock brake system and traction control
ABS Anti-lock brake system (ABS)
The anti-lock brake system prevents the wheels locking dur-
ing braking.
The anti-lock brake system (ABS) is an important part of the vehicle's active
safety system.
How the ABS works
If one of the wheels is turns too slowly in relation to the road speed, and is
close to locking, the system will reduce the braking pressure for this wheel.
The driver is made aware of this control process by a pulsating of the brake
pedal and audible noise. This is a deliberate warning to the driver that one
or more of the wheels is tending to lock and the ABS control function has
intervened. In this situation it is important to keep the brake pedal fully de-
pressed so the ABS can regulate the brake application. Do not “pump”. If you brake hard on a slippery road surface, the best possible control is re-
tained as the wheels do not lock.
However, ABS will not necessarily guarantee shorter braking distances in
all
conditions. The braking distance could even be longer if you brake on gravel
or on fresh snow covering a slippery surface.
WARNING
● The anti-lock brake system cannot defy the laws of physics. Slippery
and wet roads are dangerous even with ABS! If you notice that the ABS is
working (to counteract locked wheels under braking), 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.
● The effectiveness of ABS is also determined by the tyres fitted
⇒ page 215.
● If the running gear or brakes are modified, the effectiveness of the
ABS could be severely limited.
Traction control system (TCS)*
The traction control system prevents the drive wheels from
spinning when the vehicle is accelerating. The system al-
ways includes ABS
Description and operation of the traction control system during
acceleration (TCS)
TCS reduces engine power to help prevent the drive wheels of front-wheel
drive vehicles losing traction during acceleration. The system works in the
entire speed range in conjunction with ABS. If a malfunction occurs in the
ABS, the TCS will also be inoperative.
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TCS helps the vehicle to start moving, accelerate and climb a gradient in
slippery conditions where this may otherwise be difficult or even impossi-
ble.
The TCS is switched on automatically when the engine is started. If necessa-
ry, it may be turned on or off by briefly pushing the ESP button on the centre
console.
When the TCS is off, the warning lamp is lit. The TCS should normally be
left on. Only in exceptional circumstances, when the slipping of the wheels
is required, can they be disconnected using the ESP button, for example.
● With compact temporary spare wheel.
● When using the snow chains.
● When driving in deep snow or on loose surfaces
● When the vehicle is bogged-down, to free it by rocking.
The TCS should be switched on again as soon as possible.
WARNING
● It must be remembered that TCS cannot defy the laws of physics. This
should be kept in mind, particularly on slippery and wet roads and when
towing a trailer.
● Always adapt your driving style to suit the condition of the roads and
the traffic situation. Do not let the extra safety afforded by TCS tempt you
into taking any risks when driving, this can cause accidents.
CAUTION
● In order to ensure that TCS function correctly, all four wheels must be fit-
ted with the same tyres. Any differences in the rolling radius of the tyres can
cause the system to reduce engine power when this is not desired.
● Modifications to the vehicle (e.g. to the engine, the brake system, run-
ning gear or any components affecting the wheels and tyres) could affect
the efficiency of the ABS and TCS. XDS*
Driveshaft differential
When taking a bend, the driveshaft differential mechanism allows the outer
wheel to turn at a higher speed than the inner wheel. In this way, the wheel
that is turning faster (outer wheel) receives less drive torque than the inner
wheel. This may mean that in certain situations the torque delivered to the
inner wheel is too high, causing the wheels to spin. On the other hand, the
outer wheel is receiving a lower drive torque than it could transmit. This
causes an overall loss of lateral grip on the front axle, resulting in under-
steer or “lengthening” of the trajectory.
By using the ESP sensors and signals, the XDS system is able to detect and
correct this effect.
Through the ESP, the XDS brakes the inner wheel, thereby counteracting the
excess drive torque in this wheel. This means that the driver's desired tra-
jectory is much more precise,
The XDS system operates in combination with the ESP and is always active,
even when the traction control, TCS, is disconnected.
Electronic Stability Programme (ESP)* General notes
The Electronic Stability Programme increases the vehicle's
stability on the road.
The Electronic Stability Programme helps reduce the danger of skidding.
The Electronic Stability Programme (ESP) consists of ABS, EDL and TCS.
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Electronic Stability Programme (ESP)*
ESP reduces the danger of skidding by braking the wheels individually.
The system uses the steering wheel angle and road speed to calculate the
changes of direction desired by the driver, and constantly compares them
with the actual behaviour of the vehicle. If the desired course is not being
maintained (for instance, if the vehicle is starting to skid), then the ESP
compensates automatically by braking the appropriate wheel.
The forces acting on the braked wheel bring the vehicle back to a stable
condition. If the vehicle tends to oversteer, the system will act on the front
wheel on the outside of the turn.
WARNING
● It must be remembered that ESP cannot defy the laws of physics. This
should be kept in mind, particularly on slippery and wet roads and when
towing a trailer.
● Always adapt your driving style to suit the condition of the roads and
the traffic situation. Do not let the extra safety afforded by ESP tempt you
into taking any risks when driving, as this can cause accidents.
CAUTION
● In order to ensure that ESP functions correctly, all four wheels must be
fitted with the same tyres. Any differences in the rolling radius of the tyres
can cause the system to reduce engine power when this is not desired.
● Modifications to the vehicle (e.g. to the engine, the brake system, run-
ning gear or any components affecting the wheels and tyres) could affect
the efficiency of the ABS, EDL, ESP and TCS. Anti-lock brake system (ABS)
The anti-lock brake system prevents the wheels locking during braking
⇒ page 168.
Electronic differential lock (EDL)*
The electronic differential lock helps prevent the loss of trac-
tion caused if one of the driven wheels starts spinning.
EDL helps the vehicle to start moving, accelerate and climb a gradient in
slippery conditions where this may otherwise be difficult or even impossi-
ble.
The system will control the revolutions of the drive wheels using the ABS
sensors (in case of an EDL fault the warning lamp for ABS lights up)
⇒ page 69.
At speeds of up to approximately 80 km/h, it is able to balance out differen-
ces in the speed of the driven wheels of approximately 100 rpm caused by a
slippery road surface on one side of the vehicle. It does this by braking the
wheel which has lost traction and distributing more driving force to the oth-
er driven wheel via the differential.
To prevent the disc brake of the braking wheel from overheating, the EDL
cuts out automatically if subjected to excessive loads. The vehicle will con-
tinue to function normally without EDL. For this reason, the driver is not in-
formed that the EDL has been switched off.
The EDL will switch on again automatically when the brake has cooled
down.
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WARNING
● When accelerating on a slippery surface, for example on ice and
snow, press the accelerator carefully. Despite EDL, the driven wheels may
start to spin. This could impair the vehicle's stability.
● Always adapt your driving style to suit road conditions and the traffic
situation. Do not let the extra safety afforded by EDL tempt you into tak-
ing any risks when driving, this can cause accidents.
CAUTION
Modifications to the vehicle (e.g. to the engine, the brake system, running
gear or any components affecting the wheels and tyres) could affect the effi-
ciency of the EDL ⇒ page 189.
The traction control system (TCS)
The traction control system prevents the drive wheels from spinning when
the vehicle is accelerating ⇒ page 168.
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Driving and the environment
Running-in Running in a new engine
The engine needs to be run in over the first 1500 km.
Up to 1000 kilometres
– 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
– 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. Running in tyres and brake pads
New tyres should be run-in carefully for the first 500 km.
New brake pads should be run-in carefully for the first 200
km.
During the first 200 km, you can compensate for the reduced braking effect
by applying more pressure to the brake pedal. In case of a sharp braking,
the braking distance will be longer with new brake pads than with brake
pads which have been run-in.
WARNING
● At first, new tyres do not give maximum grip, and require running-in.
This may cause an accident. Drive particularly carefully in the first 500
km.
● New brake pads must be “run in” and do not have the correct friction
properties during the first 200 km. However, the reduced braking capaci-
ty may be compensated by pressing on the brake pedal a little harder.
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
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Driving and the environment
checked by an Authorised Service Centre more frequently than recommen-
ded 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. However, the reduced braking capacity may be
compensated by pressing on the brake pedal a little harder. This also ap-
plies 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.
● 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.
WARNING (Continued)
● 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 189, Technical modifi-
cations.
● If a brake circuit fails, the braking distance will be increased consider-
ably. Contact a specialised workshop immediately and avoid unnecessa-
ry 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 204, Topping up engine oil .
– Never tow the vehicle to start it, use jump leads if necessary
⇒ page 246.
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 63. 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.
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WARNING
The catalytic converter reaches very high temperatures! There is a 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. Diesel engine particulate filter*
The diesel engine particulate filter eliminates soot produced
by burning diesel.
Fig. 125 Vehicle data
sticker on back cover of
the Maintenance Pro-
gramme
Your vehicle is fitted with a DPF (Diesel particulate filter) if the vehicle data
sticker (back cover of the “Maintenance Programme”) lists the PR code 7GG
or 7MG ⇒ fig. 125.
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
indicator for the diesel engine particulate filter indicator 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 68.