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170Driving and operatingDrive systems
All-wheel drive
The All-wheel drive system enhances
driving characteristics and stability,
and helps to achieve the best
possible driveability regardless of
ground surface. The system is always
active and cannot be deactivated.
The torque is distributed steplessly
between the wheels of the front and
rear axle up to a torque split of 50%
to 50%. Depending on the driving
conditions, i.e. steady state driving,
All wheel drive system transfers a
minimum amount of torque for fuel
efficiency. Additionally the torque
vectoring between the rear wheels is
distributed depending on the vehicle
dynamic and surface.
This is possible because the All wheel drive system operates with two
clutches, one on each side.
For optimum system performance,
the vehicle's tyres should not have
varying degrees of wear.If a service message is displayed in
the Driver Information Centre, the
system may have limited functionality
(or be completely disabled in some
cases, i.e. the vehicle switches to
Front-wheel drive). Seek the
assistance of a workshop.
Towing the vehicle 3 266.Brakes
The brake system comprises two independent brake circuits.
If a brake circuit fails, the vehicle can
still be braked using the other brake
circuit. However, braking effect is
achieved only when the brake pedal
is depressed firmly. Considerably
more force is needed for this. The braking distance is extended. Seek
the assistance of a workshop before
continuing the journey.
When the engine is not running, the
support of the brake servo unit
disappears once the brake pedal has
been depressed once or twice.
Braking effect is not reduced, but
braking requires significantly greater
force. It is especially important to bear this in mind when being towed.
Control indicator R 3 99.
Active emergency braking 3 193.
Antilock brake system Antilock brake system (ABS)
prevents the wheels from locking.
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174Driving and operating
Control indicator k illuminates.
A status message appears in the
Driver Information Centre when TC is
deactivated.
When TC is deactivated, ESC
remains active but with higher control threshold.
TC is reactivated by pressing t again.
A status message pops up in the Driver Information Centre when TC is reactivated.
TC is also reactivated the next time
the ignition is switched on.
Fault
If there is a fault in the system the
control indicator b illuminates
continuously and a message appears
in the Driver Information Centre. The
system is not operational.
Have the cause of the fault remedied
by a workshop.
Electronic Stability Control Electronic Stability Control (ESC)
improves driving stability when
necessary, regardless of the type of
road surface or tyre grip.
As soon as the vehicle starts to
swerve (understeer/oversteer),
engine output is reduced and the wheels are braked individually.
ESC operates in combination with the
Traction Control system (TC). It
prevents the drive wheels from
spinning.
Torque distribution is a special
feature that allocates the torque to the drive wheels before the ESC
intervenes. When cornering, the
wheels on the inner curve are braked
individually. Additionally, engine
torque will be delivered to the drive wheel on the outer curve. This
reduces the tendency of
understeering and improves traction
when cornering fast.
ESC is operational after each engine
start as soon as the control indicator
b extinguishes.
When ESC operates b flashes.
9 Warning
Do not let this special safety
feature tempt you into taking risks
when driving.
Adapt speed to the road
conditions.
Control indicator b 3 100.
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Driving and operating221● The sensor in the windscreen isblocked by snow, ice, slush, mud,dirt, windscreen damage or
affected by foreign items, e.g.
stickers.
● The sun is shining directly into the camera lens.
● Close vehicles ahead
● Banked roads
● Road edges
● Roads with poor lane markings
● Sudden lighting changes
● Vehicle modifications, e.g. tyres.
Switch off the system if the system is
disturbed by tar marks, shadows,
road cracks, temporary or
construction lane markings, or other
road imperfections.9 Warning
Always keep your attention on the
road and maintain proper vehicle
position within the lane, otherwise
vehicle damage, injury or death
could occur.
Lane keep assist does not
continuously steer the vehicle.
The system may not keep the
vehicle in the lane or give an alert,
even if a lane marking is detected.
The steering of the lane keep
assist may not be sufficient to
avoid a lane departure.
The system may not detect hands-
off driving due to external
influences (road condition and
surface, weather etc). The driver
has full responsibility to control the vehicle and is always required tokeep the hands on the steeringwheel while driving.
Using the system while towing a
trailer or on slippery roads could
cause loss of control of the vehicle
and a crash. Switch the system off.Fuel
Fuel for petrol engines Only use unleaded fuel that complies
with European standard EN 228 or E DIN 51626-1 or equivalent.
The engine is capable of running with fuel that contains up to 10% ethanol
(e.g. named E10).
Use fuel with the recommended
octane rating. A lower octane rating
can reduce engine power and torque
and slightly increases fuel
consumption.Caution
Do not use fuel or fuel additives
that contain metallic compounds
such as manganese-based
additives. This may cause engine
damage.
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262Vehicle careAttach wheel wrench and with the
jack correctly aligned rotate wheel wrench until wheel is clear of the
ground.
5. Unscrew the wheel nuts. 6. Change the wheel. Spare wheel 3 262.
7. Screw on the wheel nuts.
8. Lower vehicle.
9. Install the wheel wrench ensuring that it locates securely and tighten
each nut in a crosswise
sequence. Tightening torque is
125 Nm.
10. Align the valve hole in the wheel cover with the tyre valve before
installing.
Install wheel nut caps.
11. Install vehicle jacking point cover.
12. Stow and secure the replaced wheel 3 262, the vehicle tools
3 249 and the adapter for the
locking wheel nuts 3 68.
13. Check the tyre pressure of the installed tyre and the wheel nut
torque as soon as possible.Have the defective tyre renewed or
repaired as soon as possible.
Jacking position for lifting platform
Rear arm position of the lifting
platform at the underbody.
Front arm position of the lifting
platform at the underbody.
Spare wheel Some vehicles are equipped with a
tyre repair kit instead of a spare
wheel.
If mounting a spare wheel, which is
different from the other wheels, this
wheel might be classified as a
temporary spare wheel and the
corresponding speed limits apply,
even though no label indicates this.
Seek the assistance of a workshop to
check the applicable speed limit.
The spare wheel has a steel rim.