Driving and operating179Drive 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 3 278.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 3 108.
Active emergency braking 3 202.
Antilock brake system Antilock brake system (ABS)
prevents the wheels from locking.
Driving and operating181The electric parking brake can always
be activated, even if the ignition is off.
Do not operate electric parking brake
system too often without engine
running as this will discharge the
vehicle battery.
Releasing
Switch on ignition. Keep foot brake
pedal depressed and then push
switch m.
Drive away function
Vehicles with manual transmission:
Depressing the clutch pedal and then slightly releasing the clutch pedal and
slightly depressing the accelerator
pedal releases the electric parking
brake automatically. This is not
possible when switch m is pulled at
the same time.
Vehicles with automatic transmission: Engaging D and then depressing the
accelerator pedal releases the
electric parking brake automatically.
This is not possible when switch m is
pulled at the same time.Dynamic braking when vehicle is
moving
When the vehicle is moving and the
switch m is kept pulled, the electric
parking brake system will decelerate the vehicle, but will not apply
statically.
As soon as the switch m is released,
dynamic braking will be stopped.
Automatic applying
If the vehicle is equipped with
automatic transmission and adaptive cruise control is active, electric
parking brake is applied automatically when vehicle is stopped by the
system for more than two minutes.
Parking brake releases automatically
after moving off.
Functionality check
When the vehicle is not moving, the
electric parking brake might be
applied automatically. This is done to
check the system.Fault
Failure mode of electric parking brake
is indicated by a control indicator j
and by a vehicle message which is
displayed in the Driver Information
Centre. Vehicle messages 3 124.
Apply electric parking brake: pull and
hold the switch m for more than
five seconds. If control indicator m
illuminates, electric parking brake is
applied.
Release electric parking brake: push
and hold the switch m for more than
two seconds. If control indicator m
extinguishes, electric parking brake is
released.
Control indicator m flashes: electric
parking brake is not fully applied or
released. When continuously
flashing, release electric parking
brake and retry applying.
Brake assist If brake pedal is depressed quickly
and forcefully, maximum brake force
is automatically applied.
182Driving and operatingOperation of brake assist might
become apparent by a pulse in the brake pedal and a greater resistancewhen depressing the brake pedal.
Maintain steady pressure on the
brake pedal as long as full braking is
required. Maximum brake force is
automatically reduced when brake
pedal is released.
Hill start assist The system helps prevent unintendedmovement when driving away on
inclines.
When releasing the brake pedal after
stopping on an incline, brakes remain
on for further two seconds. The
brakes release automatically as soon as the vehicle begins to accelerate.Ride control systems
Traction Control system The Traction Control system (TC) is a
component of the Electronic Stability
Control (ESC).
TC improves driving stability when
necessary, regardless of the type of
road surface or tyre grip, by
preventing the drive wheels from
spinning.
As soon as the drive wheels starts to spin, engine output is reduced and
the wheel spinning the most is braked individually. This considerably
improves the driving stability of the
vehicle on slippery road surfaces.
TC is operational after each engine
start as soon as the control indicator
b extinguishes.
When TC 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 3 109.
Deactivation
TC can be switched off when spinning of drive wheels is required: press t
briefly.
Driving and operating183
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 3 109.
Driving and operating185● adaptive cruise control
● all-wheel drive
● engine sound enhancement
● instrument cluster theme
SPORT mode
The settings of the systems are
adjusted for a sportier driving style:
● Damping of shock absorbers is set up for increased handling andagility.
● The engine reacts more quickly to accelerator pedal changes.
● Steering support is sportier.
● Automatic transmission shift points optimised for sporty
driving.
● Adaptive cruise control is adjusted for a sportier driving
style.
● All-wheel drive supports active sporty driving of the vehicle.
● Engine sound enhancement intensifies interior engine sound
in a sporty manner.
● Cluster theme changes to sport.
TOUR modeTOUR mode adjusts the settings of
the systems for a comfortable driving
style.
● Damping of shock absorbers is adapted for increased driving
comfort.
● Steering efforts are reduced. ● Adaptive cruise control is adjusted for a more relaxed
driving style.
AUTO mode
All settings of the systems are preset
to standard values optimised for daily driving (default mode). This is the fully
adaptive mode, adjusting systems to
both comfort and sport settings
depending on driving style and driving
situation.
Adaptive drive mode control
Within each manually selected driving mode SPORT , TOUR or AUTO , Drive
Mode Control (DMC) detects and
analyses continuously the driving situation and the driver's driving style.
If necessary, DMC automatically
adjusts damping and steering for the
duration of the occuring situation.
188Driving and operatingControl indicator m 3 112.
Switching on
Press m; control indicator m in
instrument cluster illuminates white.
Activation
Accelerate to the desired speed and
turn thumb wheel to SET/-, the
current speed is stored and
maintained. Control indicator m in
instrument cluster illuminates green.
On Mid- and Uplevel display m
illuminates green and set speed is
indicated. Accelerator pedal can be
released.
Vehicle speed can be increased by
depressing the accelerator pedal.
When the accelerator pedal is
released, the previously stored speed
is resumed.
Cruise control remains activated
while gearshifting.
Increase speed With cruise control active, hold thumb
wheel turned to RES/+ or briefly turn
to RES/+ repeatedly: speed
increases continuously or in small
increments.
Alternatively accelerate to the desired speed and store by turning to SET/-.Reduce speed
With cruise control active, hold thumb
wheel turned to SET/- or briefly turn to
SET/- repeatedly: speed decreases
continuously or in small increments.
Deactivation Press y; control indicator m in
instrument cluster illuminates white.
On Mid- or Uplevel display m
changes to white.
Cruise control is deactivated, but not
switched off. Last stored speed
remains in memory for later speed
resume.
Automatic deactivation: ● Vehicle speed is below approx. 30 km/h.
● Vehicle speed drops more than 25 km/h below the set speed.
● The brake pedal is depressed.
● The clutch pedal is depressed for
a few seconds.
● The selector lever is in N.
● Engine speed is in a very low range.
Driving and operating195Detecting the vehicle ahead
The green illuminated vehicle ahead
control indicator A is displayed when
the system detects a vehicle in the driving path. The range of the sensors
is between 25 and 150 metres
depending on vehicle speed.
Forward collision alert 3 198.
If this symbol does not display, or
displays briefly, adaptive cruise
control will not respond to vehicles ahead.
Deactivation Adaptive cruise control is deactivatedby the driver when:
● y is pressed.
● Brake pedal is applied.
● Clutch pedal is depressed for more than four seconds.
● Selector lever of automatic transmission is moved to N.
The system is also automatically deactivated when:
● Vehicle speed accelerates above
190 km/h or slows down below
25 km/h, on vehicles with
automatic transmission it slows
down to a stop without
deactivating within five minutes.
● The Traction Control system is deactivated or operating.
● The Electronic Stability Control is
deactivated or operating.
● There is no traffic and nothing detected on the road sides forapprox. one minute. In this casethere are no radar echoes and
the sensor may report that it is
blocked.
● The active emergency braking system is applying the brakes.
● Driving on steep inclines.
● The radar sensor is blocked by an ice or water film.● A fault is detected in the radar,camera, engine or brake system.
● The brakes need to cool down.
Additionally, the system is
automatically deactivated on vehicles
with automatic transmission (full
speed range adaptive cruise control)
when:
● The incline uphill or downhill is greater than 20 %.
● The electric parking brake is applied.
● The vehicle is being held to a stop
by the system for more than
five minutes.
● The vehicle stops, the driver's seat belt is unbuckled and thedriver's door is opened.
When adaptive cruise control is
deactivated, the control indicator m
changes from green to white and a
pop-up message is displayed in the
Driver Information Centre.
The stored speed is maintained.
196Driving and operating
On Midlevel display, the stored speedis indicated in brackets in the Driver
Information Centre when the system
is deactivated but not switched off.
On Uplevel display, the adaptive
cruise control symbol C changes
from green to white when the system
is deactivated but not switched off.
9 Warning
When adaptive cruise control is
deactivated, the driver must take
over full brake and engine control
immediately.
Switching off
Press C to switch off adaptive cruise
control. The control indicator C in the
Driver Information Centre
extinguishes. The stored speed is
deleted.
Switching off the ignition also
switches off adaptive cruise control
and deletes the stored speed.
Driver's attention ● Use adaptive cruise control carefully on bends or mountain
roads, as it can lose the vehicle
ahead and needs time to detect it again.
● Do not use the system on slippery roads as it can create
rapid changes in tyre traction
(wheel spinning), so that you
could lose control of the vehicle.
● Do not use adaptive cruise control during rain, snow or
heavy dirt, as the radar sensor
can be covered by a water film,
dust, ice or snow. This reduces or
suppresses completely the
visibility. In case of sensor
blockage, clean the sensor
cover.System limits9 Warning
The system's automatic brake
force does not permit hard braking and the braking level may not be
sufficient to avoid a collision.
● After a sudden lane change, the system needs a certain time to
detect the next preceding
vehicle. So if a new vehicle is
detected, the system may
accelerate instead of braking.
● Adaptive cruise control does ignore the oncoming traffic.
● Adaptive cruise control does not consider pedestrians and
animals for braking and driving
off.
● Adaptive cruise control considers
stopped vehicles only at low
speed.