Driving and operating175If 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 3 277.Brakes
The brake system comprises twoindependent 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 beforecontinuing 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 3 107.
Active emergency braking 3 200.
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 3 108.
Adaptive brake light During full braking, all three brake
lights flash for the duration of ABS
control.
176Driving and operatingFault9Warning
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.
Parking brake
9 Warning
Before leaving the vehicle, check
parking brake status. Control
indicator m must illuminate
constantly.
Electric parking brake
Applying when vehicle is stationary
9 Warning
Pull switch m for a minimum of
1 second until control indicator m
illuminates constantly and electric
parking brake is applied 3 107.
The electric parking brake
operates automatically with
adequate force.
Before leaving the vehicle, check
the electric parking brake status.
Control indicator m 3 107.
The 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.
Driving and operating191The system is also automatically
deactivated when:
● Vehicle speed accelerates above
190 km/h or slows down below
25 km/h . Vehicles with automatic
transmission slows down to a
stop without deactivating within
5 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 for
approx. 1 minute. In this case
there 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
5 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 C
changes from green to white and a
pop-up message is displayed in the
Driver Information Centre.
The stored speed is maintained.The stored speed is indicated in
brackets in the Driver Information
Centre when the system is
deactivated but not switched off.
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 the system
Press v to switch off adaptive cruise
control. The control indicator C
extinguishes in the Driver Information Centre. The stored speed is deleted.
Switching off the ignition also
switches off adaptive cruise control
and deletes the stored speed.
192Driving and operatingDriver'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.
● Do not use adaptive cruise control when towing a trailer.
● Do not use adaptive cruise control on roads with an incline ofmore than 10%.
Bends
The adaptive cruise control calculates
a predicted path based on the
centrifugal force. This predicted path
considers the current bend
characteristic, but cannot consider a
future bend change. The system may lose the current vehicle ahead or
consider a vehicle which is not in the
actual lane. This can happen when
entering or exiting a bend or if the
bend gets stronger or weaker. The
camera applies a certain correction
based on the detectable lane
markings. The control indicator A will
extinguish, if a vehicle ahead is no longer detected.
194Driving and operatingRadar unit
The radar unit is mounted behind the
radiator grille or 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 adjust the radar unit
position.
Settings
A vehicle message and chime
reminds the driver to drive off when
the adaptive cruise control holds the
vehicle at standstill. This function
named Go Notifier can be activated
and deactivated in the vehicle
personalisation menu in the Info
Display.
Vehicle personalisation 3 124.
Fault
If the adaptive cruise control does not
work due to temporary conditions
(e.g. blockage by ice, overheated
brakes or low speed manoeuvres) or
if there is a permanent system error,
a message is displayed in the Driver
Information Centre.
Vehicle messages 3 123.
Intelligent adaptive cruise control
This feature is an enhancement to
adaptive cruise control. It updates the
set speed to a new detected speed
limit automatically, if the driver has
forgotten to adapt the set speed. The preferred usage of this function is
outside cities or villages. It uses
information provided by the traffic
sign assistant 3 220.
Note
Perform updates of your
navigational maps regularly and
make sure that the correct SD-card
is inserted in the navigation map
card port.
Note
Speed limit signs which are
combined with add-on signs, e.g.
time, weather or vehicle type
limitations, are not considered by
this system.
Driving and operating199General information9Warning
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 on vehicles only, but may reactalso to other objects.
In the following cases, forward
collision alert may not detect a vehicle ahead or sensor performance is
limited:
● driving on winding or hilly roads● during nighttime driving
● weather limits visibility, such as fog, rain, or snow
● the sensor in the windscreen 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 front camera in
the windscreen is used to detect the
distance of a vehicle directly ahead in
the vehicle's 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.On Baselevel display, choose Info
Menu ? and choose following
distance indication page 3 112.
On Mid- and Uplevel display, select
Info menu via steering wheel buttons
and press å to select following
distance indication 3 112.
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: -.- sec.
200Driving and operating
If Adaptive cruise control is active,
this page shows the alert sensitivity
setting instead of following distance setting 3 185.
System limitations
In the following cases, following
distance indication sensor
performance is limited:
● Driving on winding or hilly roads.
● During nighttime driving.
● Weather limits visibility, such as fog, rain, or snow.
● The sensor is blocked by snow, ice, slush, mud, dirt, windscreen
damage or affected by foreign
items, e.g. stickers.
Active emergency braking Active emergency braking is part of
the forward collision system 3 124. It
can help to reduce the damage and
injury from crashes with vehicles,
pedestrians and obstacles directly
ahead, when a collision can no longer be avoided either by manual braking
or by steering. Before the active
emergency braking applies, the driver
is warned by the Forward collision
alert 3 196 or the Front pedestrian
protection alert 3 203.
The feature uses various inputs (e.g.
camera sensor, radar sensor, brake
pressure, vehicle speed) to calculate
the probability of a frontal collision.9 Warning
This system is not intended to
replace the driver's responsibility for driving the vehicle and looking
ahead. Its function is limited to
supplemental use only to reduce
the vehicle speed before a
collision.
The system may not react to
animals. After a sudden lane
change, the system needs a
certain time to detect the next
preceding vehicle.
The driver must always be ready
to take action and apply the brakes and steer to avoid collisions.
Functionality
The system includes: ● brake preparation system
● emergency automatic braking
● forward looking brake assist
● intelligent brake assist (only with radar sensor)
● front pedestrian protection system
202Driving and operating9Warning
Active emergency braking is not
designed to apply hard
autonomous braking or to
automatically avoid a collision. It is designed to reduce the vehicle
speed before a collision. It may not
react to animals. After a sudden
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 must always be
ready to take action and apply the brakes and steer to avoid
collisions.
The system is designed to work with
all occupants wearing their seat belts.
Intelligent Brake Assist
If the vehicle is equipped with radar
sensor Intelligent brake assist may
activate when the brake pedal is
applied quickly by providing a boost
to braking based on the speed of
approach and distance to a vehicle
ahead.
Minor brake pedal pulsations or pedal movement during this time is normal
and the brake pedal should continue
to be applied as needed. Intelligent
brake assist will automatically
disengage only when the brake pedal is released.9 Warning
Intelligent brake assist may
increase vehicle braking in
situations when it may not be
necessary. You could block the
flow of traffic. If this occurs, take
your foot off the brake pedal and
then apply the brakes as needed.
Front pedestrian protection 3 203.
Deactivation Active emergency braking can be
deactivated in the personalisation
menu 3 124. If deactivated a
message is displayed in the Driver
Information Centre.
We recommend to deactivate the
system in the vehicle personalisation
in the following cases:
● when the vehicle is being towed
● before using an automatic car wash with ignition switched on
● if the windscreen has been damaged close to the camera
● if the front bumper has been damaged
System limitations 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 if the situation and the
surroundings permit.