174Driving and operatingBrakes
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 3 106.
Antilock brake system
Antilock brake system (ABS)
prevents the wheels from locking.ABS starts to regulate brake pressure as soon as a wheel shows a tendency to lock. The vehicle remains
steerable, even during hard braking.
ABS control is made apparent
through a pulse in the brake pedal
and the noise of the regulation
process.
For optimum braking, keep the brake
pedal fully depressed throughout the
braking process, despite the fact that the pedal is pulsating. Do not reduce
the pressure on the pedal.
After starting off, the system performs
a self-test which may be audible.
Control indicator u 3 107.
Adaptive brake light During full braking, all three brake
lights flash for the duration of ABS
control.
Fault9 Warning
If there is a fault in the ABS, the
wheels may be liable to lock due
to braking that is heavier than
normal. The advantages of ABS are no longer available. During
hard braking, the vehicle can no longer be steered and may
swerve.
Have the cause of the fault remedied
by a workshop.
Driving and operating179Interactive driving systemFlex Ride
Flex Ride driving system allows the
driver to select between three driving
modes:
● SPORT mode: press SPORT,
LED illuminates.
● TOUR mode: press TOUR, LED
illuminates.
● NORMAL mode: neither SPORT
nor TOUR is pressed, no LED
illuminates.
Deactivate SPORT mode and TOUR
mode by pressing corresponding
button once more.
In each driving mode Flex Ride
networks the following electronic
systems:
● Continuous Damping Control
● Accelerator Pedal Control
● Steering Control
● All-wheel drive
● Electronic Stability Control (ESC)● Antilock Brake System (ABS)
with cornering brake control
(CBC)
● Automatic transmission
SPORT mode
The settings of the systems are
adapted to a sportier driving style:
● Damping of shock absorbers reacts more stiffly to providebetter contact with the road
surface.
● The engine reacts more quickly to the accelerator pedal.
● Steering support is reduced.
● Engine torque of All-wheel drive is distributed more to the rear
axle.
● Shift points of automatic transmission occur later.
● Depending on the instrument cluster the colouring of the
display will be adapted.
TOUR mode
The settings of the systems are
adapted to a comfort driving style:
● Damping of shock absorbers reacts more softly.
● Accelerator pedal reacts with standard settings.
Driving and operating181OPC Flex Ride driving system allows
the driver to select between three
driving modes:
● OPC mode: press OPC, LED
illuminates.
● SPORT mode: press SPORT,
LED illuminates.
● NORMAL mode: neither SPORT
nor OPC is pressed, no LED
illuminates.
Deactivate SPORT mode and OPC
mode by pressing corresponding
button once more.
In each driving mode OPC Flex Ride
networks the following electronic
systems:
● Continuous Damping Control
● Accelerator Pedal Control
● Steering Control
● All-wheel drive
● Electronic Stability Control (ESC)
● Antilock Brake System (ABS) with cornering brake control
(CBC)
● Automatic transmissionOPC mode
The drive dynamic characteristics are
adapted to high performance
settings.
Depending on the instrument cluster the colouring of the display will beadapted.
SPORT mode
The settings of the systems are
adapted to a sportier driving style.
NORMAL mode
In NORMAL mode, when neither SPORT nor OPC is pressed, all
settings of the systems are adapted
to standard values.
Personalised settings in the OPC mode
The driver can select the functions of
the OPC mode when OPC is pressed.
Select the relevant settings in
Settings , I Sport Mode in the Colour-
Info-Display.
Colour-Info-Display 3 118.
Vehicle personalisation 3 121.Driver assistance
systems9 Warning
Driver assistance systems are
developed to support the driver
and not to replace the driver's
attention.
The driver accepts full
responsibility when driving the
vehicle.
When using driver assistance
systems, always take care
regarding the current traffic
situation.
Cruise control
The cruise control can store and
maintain speeds of approx. 30 to
200 km/h. Deviations from the stored
speeds may occur when driving uphill or downhill.
For safety reasons, the cruise control cannot be activated until the brake
pedal has been operated once.
Activating in first gear is not possible.
188Driving and operating
The selected following distance is
indicated by filled distance bars in the
adaptive cruise control page.
Note that the following distance
setting is shared with the sensitivity
setting of forward collision alert
3 192.
Example: If setting 3 (far) is selected,
then the driver is warned sooner
before a possible collision, also if
adaptive cruise control is inactive or
switched off.
9 Warning
The driver accepts full
responsibility for the appropriate
following distance based on traffic, weather and visibility conditions.
Following distance must be
adjusted or the system switched
off when required by the prevailing
conditions.
Detecting the vehicle ahead
The green illuminated vehicle ahead
control indicator A is displayed when
the system detects a vehicle in the driving path.
Forward collision alert 3 192.
If this symbol does not display, or displays only briefly, adaptive cruise
control will not respond to vehicles
ahead.
Deactivation
Adaptive cruise control is deactivated by the driver when:
● y is pressed.
● Brake pedal is applied.
● Clutch pedal is depressed for more than four seconds.
● Gear 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
15 km/h (on vehicles with
automatic transmission it slows
down to a stop without
deactivating within two minutes).
● The Traction Control system is operating.
● The Electronic Stability Control is
operating.
● There is no traffic and nothing detected on the road sides for
several minutes. In this case
there are no radar echoes and
the sensor may report that it is blocked.
Driving and operating189● The collision imminent brakingsystem is applying the brakes.
● The radar sensor is blocked by an ice or water film.
● A fault is detected in the radar, engine or brake system.
Additionally, the system is
automatically deactivated on vehicles
with automatic transmission (full
speed range adaptive cruise control)
when:
● The electric parking brake is applied.
● The vehicle is being held to a stop
by the system for more than
two minutes.
● The vehicle stops, the driver's seat belt is released and the
driver's door is opened.
When adaptive cruise control is
deactivated, the control indicator m
and C in the Driver Information
Centre changes from green to white
and a pop-up message is displayed.
The stored speed is maintained. 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.
Switching off
Press C to switch off adaptive cruise
control. The control indicator m or C
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 need 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 limits ● 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.
Driving and operating191Hill and trailer considerations
System performance on hills depends
on vehicle speed, vehicle load, traffic
conditions and the road gradient. It
may not detect a vehicle in your path
while driving on hills. On steep hills,
you may have to use the accelerator
pedal to maintain your vehicle speed.
When going downhill you may have to brake to maintain or reduce your
speed.
Note that applying the brake
deactivates the system. It is not
recommended to use adaptive cruise
control on steep hills.
Radar unit
The radar unit is mounted behind the
radiator grille below the brand
emblem.
9 Warning
The radar unit was aligned
carefully during manufacture.
Therefore, in the event of a front-
end impact, do not use the system. The front bumper may appear to
be intact, however the sensor
behind can be out of position and
react incorrectly. After an
accident, consult a workshop to
verify and correct the adaptive
cruise control sensor position.
Settings
Settings can be changed in thevehicle personalisation menu in the
Colour-Info-Display.
Select the relevant setting in Settings,
I Vehicle in the Colour-Info-Display.
Colour-Info-Display 3 118.
Vehicle personalisation 3 121.
Fault If the adaptive cruise control does not
work due to temporary conditions
(e.g. blockage by ice) or if there is a
permanent system error, then a
message is displayed in the Driver
Information Centre.
Driving and operating195General information for both
variants of forward collision alert9 Warning
Forward collision alert is just a
warning system and does not
apply the brakes. When
approaching a vehicle ahead too
rapidly, it may not provide you
enough time to avoid a collision.
The driver accepts full
responsibility for the appropriate
following distance based on traffic, weather and visibility conditions.
The complete attention of the
driver is always required while
driving. The driver must always be
ready to take action and apply the
brakes.
System limitations
Forward collision alert is designed to warn for vehicles only, but may also
react to other objects.
In the following cases, forward
collision alert may not detect a vehicle ahead or sensor performance may be limited:
● on winding roads
● when weather limits visibility, such as fog, rain, or snow
● when the sensor is blocked by snow, ice, slush, mud, dirt,
windscreen damage or affected
by foreign items, e.g. stickers
Following distance indication
The following distance indication
displays the distance to a preceding
moving vehicle. The system uses,
depending on the vehicle equipment,
either the radar behind the radiator
grille or the front camera in the
windscreen to detect the distance of
a vehicle directly ahead in your path. It is active at speeds above 40 km/h.
When a preceding vehicle is detected
ahead, the distance is indicated in
seconds, displayed on a page in the
Driver Information Centre 3 111.On Baselevel display set Settings
X with the Menu button and select
Following distance indication via the
adjuster wheel on the turn signal lever
3 111.
On Midlevel or Uplevel display, select
Info menu and press o to select
Following distance indication 3 111.
The minimum indicated distance is
0.5 seconds.
If there is no vehicle ahead or the vehicle ahead is out of range, two
dashes will be displayed: -.- s.
If Adaptive cruise control is active,
this page shows the following
distance setting instead 3 184.
Driving and operating197sudden lane change, the system
needs a certain time to detect the
next preceding vehicle.
The complete attention of the
driver is always required while
driving. The driver shall always be ready to take action and apply the
brakes and steer to avoid
collisions. The system is designed to work with all occupants wearingtheir seat belts.
System limitations
The active emergency braking has
limited or no function during rain,
snow or heavy dirt, as the radar
sensor can be covered by a water
film, dust, ice or snow. In case of
sensor blockage, clean the sensor
cover.
In some cases, the active emergency braking system may provide an
automatic braking in situations that
seem to be unnecessary, for instance
in parking garages, due to traffic signs in a curve or due to vehicles in
another lane. This is normal
operation, the vehicle does not need
service. Firmly apply the accelerator
pedal to override the automatic
braking.
Settings
Settings can be changed in the vehicle personalisation menu in the
Colour-Info-Display.
Select the relevant setting in Settings,
I Vehicle in the Colour-Info-Display.
Colour-Info-Display 3 118.
Vehicle personalisation 3 121.
Fault
In the event of a system service
requirement, a message is displayed
in the Driver Information Centre.
If the system does not work as it
should do, vehicle messages are
displayed in the Driver Information
Centre.
Vehicle messages 3 120.
Parking assist
9 Warning
The driver bears full responsibility
for the parking manoeuvre.
Always check the surrounding
area when driving backwards or
forwards while using parking
assist system.