Page 185 of 293

Driving and operating183Depending on the vehicle's
equipment, there are two variants of
the forward collision alert available:
● Forward collision alert based on
radar system
on vehicles equipped with adaptive cruise control 3 176.
● Forward collision alert based on
front camera system
on vehicles with traditional cruise
control 3 173.
Forward collision alert based on
radar system
The system uses the radar sensor
behind the radiator grille to detect a
vehicle directly ahead, in your path,
within a distance of max. 150 metres.
Activation
Forward collision alert operates
automatically above walking speed,
provided that Auto collision
preparation setting is not deactivated
in the vehicle personalisation menu
3 125.Selecting the alert sensitivity
The alert sensitivity can be set to
near, medium or far.
Press E; the current setting is shown
in the Driver Information Centre.
Press E again to change the alert
sensitivity. The setting is also displayed in the top line of the Driver
Information Centre.
Note that the alert timing sensitivity
setting is shared with the following
distance setting of the adaptive cruise control. So changing the alert timing
sensitivity changes the adaptive
cruise control following distance
setting.
Alerting the driver
The vehicle ahead control indicator
A illuminates green in the instrument
cluster when the system has detected
a vehicle in the driving path.
Page 186 of 293

184Driving and operatingCaution
The colour lighting of this control
indicator does not correspond to
local traffic laws on following
distance. The driver bears full
responsibility for maintaining safe
following distance according to
applicable traffic rules, weather
and road conditions etc. at all
times.
When the distance to a preceding
moving vehicle gets too small or when
approaching another vehicle too rapidly and a collision is imminent the collision alert symbol pops-up in the
Driver Information Centre and a
warning chime sounds. Depress the
brake pedal, if it is required by the
situation.
Settings
Settings can be changed in the
vehicle personalisation menu in the
Info-Display.
Select the relevant setting in
Settings in the Info-Display.
Vehicle personalisation 3 125.
Forward collision alert based on
front camera system
Forward collision alert uses the front
camera system in the windscreen to
detect a vehicle directly ahead, in
your path, within a distance of approx. 60 metres.
Activation
Forward collision alert operates
automatically above 40 km/h, if it is not deactivated by pressing V, see
below.
Selecting the alert sensitivity
The alert sensitivity can be set to
near, medium or far.
Press V; the current setting is shown
in the Driver Information Centre.
Press V again to change the alert
sensitivity.
Page 187 of 293

Driving and operating185Alerting the driver
The vehicle ahead control indicator
A illuminates green in the instrument
cluster when the system has detected
a vehicle in the driving path.Caution
The colour lighting of this control
indicator does not correspond to
local traffic laws on following
distance. The driver bears full
responsibility for maintaining safe
following distance according to
applicable traffic rules, weather
and road conditions etc. at all
times.
When the distance to a preceding
moving vehicle gets too small or when
approaching another vehicle too rapidly and a collision is imminent the collision alert symbol pops-up in the
Driver Information Centre and a
warning chime sounds. Depress the
brake pedal, if it is required by the
situation.
Deactivation
The system can be deactivated.
Press V repeatedly until Forward
Collision Alert Off appears in the
Driver Information Centre.
General 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
The system is designed to warn only for vehicles, but may react also onother metallic objects.
In the following cases, forward
collision alert may not detect a vehicle ahead or sensor performance is
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,
Page 188 of 293

186Driving and operatingdepending 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 3 117.
Press MENU on the turn signal lever
to select Vehicle Information
Menu ? and turn the adjuster
wheel to choose following distance
indication page.
The minimum indicated distance is
0.5 s.
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 alert sensitivity
setting instead of following distance setting. 3 176.
Active Emergency Braking
Active emergency braking can help to reduce the damage and injury from
crashes with vehicles 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 3 182.
The feature uses various inputs (e.g.
radar sensor, brake pressure, vehicle speed) to calculate the probability of
a frontal collision.
Active emergency braking operates automatically above walking speed,
provided that Auto collision
preparation setting is not deactivated
in the vehicle personalisation menu
3 125.
The system includes: ● brake preparation system
● emergency automatic braking
● forward looking brake assist9Warning
This system is not intended to
replace the driver responsibility of driving the vehicle and looking
ahead. Its function is limited to
supplemental use only. The driver shall continue to apply the brake
pedal as the driving situation
dictates.
Page 189 of 293

Driving and operating187Brake preparation system
When approaching a vehicle ahead
so quickly that a collision is likely, the brake preparation system slightlypressurises the brakes. This reduces
the response time, when a manual or automatic braking is requested.
The brake system is prepared so that braking can occur more rapidly.
Emergency automatic braking
After the brake preparation and just
before the imminent collision, this
function automatically applies limited
braking to reduce the impact speed of
the collision.
Forward looking brake assist
In addition to brake preparation
system and emergency automatic
braking, the forward looking brake
assist function makes the brake assist more sensitive. In this way,
depressing the brake pedal slightly
results immediately in a strong
braking. This function helps the driver
brake quicker and stronger before the imminent collision.9 Warning
Active emergency braking is not
designed to apply strong
autonomous braking or to avoid automatically a collision. It is
designed to reduce the vehicle
speed before collision. It may not
react on stopped vehicles,
pedestrians or 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 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 wearing their 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 seldom cases the active
emergency braking system may
provide a short automatic braking in
situations that seem to be
unnecessary, for instance due to
traffic signs in a curve or due to
vehicles in another lane. This is
acceptable 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
Info-Display.
Select the relevant setting in
Settings in the Info-Display.
Vehicle personalisation 3 125.
Fault
In the event of a system service
requirement, a message is displayed
in the Driver Information Centre.
Page 190 of 293

188Driving and operatingIf the system does not work as it
should, vehicle messages are
displayed in the Driver Information
Centre.
Vehicle messages 3 123.
Parking assist Front-rear parking assist9 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.
The front-rear parking assist
measures the distance between the vehicle and obstacles in front of and
behind the vehicle. It informs and
warns the driver by giving acoustic
signals and display indication.
It uses two different acoustic warning
signals for the front and rear
monitoring areas, each with a
different tone frequency. The signal
for front obstacles sounds via the
front speakers, for rear obstacles it
sounds via the rear speakers.
The system has four ultrasonic
parking sensors each in the rear and
front bumper.
Activation
When reverse gear is engaged, the
front and rear parking assist is ready
to operate.
The system is also activated
automatically at a speed up to
11 km/h.
An illuminated LED in the parking
assist button r indicates that the
system is ready to operate.
If r is switched off within an ignition
cycle, the front parking assist is
deactivated. If vehicle speed has exceeded 25 km/h beforehand,
parking assist will be reactivated when speed drops below 11 km/h.
Indication
The system warns the driver with
acoustic signals against potentially
hazardous obstacles behind and in
front of the vehicle.
Page 191 of 293

Driving and operating189Depending on which side of the
vehicle is closer to an obstacle, you
will hear acoustic warning signals on
the respective side of the vehicle. The
interval between the sounds
becomes shorter as the vehicle gets
closer to that obstacle. When the
distance is less than approx. 30 cm,
the sound is continuous.
Additionally, the distance to rear and
front obstacles is displayed by
changing distance lines in the Driver
Information Centre 3 117 or,
depending on the version, on the Info- Display 3 121.Rear obstacles are indicated
acoustically and visually at the same
time.
Front obstacles are indicated visually
first. At distances less than 80 cm an
acoustic signal also sounds.
The distance indication can be
inhibited by vehicle messages with a higher priority. After dismissing themessage distance indication appears again.
Deactivation
The rear parking assist automatically
switches off when reverse gear is
disengaged.
The front parking assist is deactivated
automatically at a speed above
11 km/h.
Manual deactivation is also possible by pressing the parking assist button
r .
When the system is deactivated
manually, the LED in the button
extinguishes and Park Assist Off
pops-up in the Driver Information
Centre.
After a manual deactivation, the front- rear parking assist is activated again
if r is pressed or if reverse gear is
engaged.
The complete system can be
manually deactivated in the vehicle
personalisation menu in the
Info-Display. It remains deactivated
Page 192 of 293

190Driving and operatingduring the ignition cycle or until
activation in personalisation menu
again. Vehicle personalisation 3 125.
When using the trailer hitch change
the configuration settings in the
vehicle personalisation menu in the
Info-Display. Vehicle personalisation
3 125.
Fault
In the event of a fault or if the system does not work temporarily, e.g.because of high external noise level
or other interference factors, a
message pops-up in the Driver
Information Centre.
Vehicle messages 3 123.
Basic notes on parking assist
systems9 Warning
Under certain circumstances,
various reflective surfaces on
objects or clothing as well as
external noise sources may cause the system to fail to detect
obstacles.
Special attention must be paid to
low obstacles which can damage
the lower part of the bumper.Caution
Performance of the system can be reduced when sensors are
covered, e.g. by ice or snow.
Performance of the parking assist
system can be reduced due to
heavy loading.
Special conditions apply if there
are taller vehicles in the vicinity
(e.g. off-road vehicles, mini vans,
vans). Object identification and correct distance indication in the
upper part of these vehicles
cannot be guaranteed.
Objects with a very small reflection
cross-section, e.g. objects of
narrow size or soft materials, may
not be detected by the system.
Parking assist systems do not
detect objects outside the
detection range.
Note
The parking assist system
automatically detects factory-fitted
towing equipment. It is deactivated
when the connector is plugged in.
It is possible that the sensor detects a non-existing object (echo
disturbance) caused by external acoustical or mechanic
disturbances.
Note
If engaging a forward gear and
exceeding a certain speed, the rear
parking assist will be deactivated
when the rear carrier system is
extended.
If engaging reverse gear first, the
parking assist will detect the rear
carrier system and provide a buzzing
sound. Press r briefly to
deactivate the parking assist.
Side blind spot alert
The side blind spot alert system
detects and reports objects on either
side of the vehicle, within a specified
"blind spot" zone. The system
displays a visual alert in each exterior