194Driving and operating
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.
Deactivation The system can be deactivated.
On forward collision alert with radar
sensor the system can be disabled by
the personalisation menu, 3 124.
On forward collision alert with front
camera press V repeatedly until
Forward Collision Alert Off appears in
the Driver Information Centre.
If the forward collision alert was
deactivated, alert sensitivity is set to
"medium" when ignition is switched on next time.
The last selected setting will be stored
when the ignition is switched off.
General information9 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 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:
● 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 front camera in
Driving and operating195the windscreen and the Radar sensor
are used to detect the distance of a
vehicle directly ahead in the vehicle's
path. It is active at speeds above
25 mph.
When a preceding vehicle is detected
ahead, the distance is indicated in
seconds, displayed on a page in the
Driver Information Centre.
On Midlevel display, choose Info
Menu ? via MENU on the turn
signal lever and turn the adjuster wheel to choose following distance
indication page, 3 114On Uplevel display, select Info menu
via steering wheel buttons and press o to select following distance
indication 3 114.
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.
If Adaptive cruise control is active,
this page shows the alert sensitivity
setting instead of following distance
setting. 3 184.
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 3 192.
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 responsibility for driving the vehicle and looking
ahead. Its function is limited to
196Driving and operatingsupplemental use only to reduce
the vehicle speed before a
collision.
The system may not react for
pedestrians or animals. After a
sudden lane change, the system
needs a certain time to detect the
next preceding vehicle.
The driver shall always be ready to take action and apply the brakes
and steer to avoid collisions.
Functionality
If equipped only with front camera the active emergency braking operates in
forward gear above walking speed up to 53 mph.
With radar sensor active emergency
braking operates in forward gear
above walking speed at all speeds.
A precondition is that forward collision
alert with front camera system is not
deactivated by pressing V on the
steering wheel 3 192or, with radar
sensor, that it is not deactivated in the vehicle personalisation menu 3 124.
The system includes:
● brake preparation system
● emergency automatic braking
● forward looking brake assist
● intelligent brake assist (only with radar sensor)
Brake preparation system
When approaching a vehicle ahead
so quickly that a collision is likely, the brake preparation system slightly
pressurizes 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.
If equipped only with front camera the
system operates up to a speed of 50
mph.
Emergency automatic braking After activation of brake preparation
system and just before the imminent
collision, this function automatically
applies limited braking to reduce the
impact speed of the collision or
prohibit a crash. Depending on the situation, the vehicle mayautomatically brake moderately or
hard. This front automatic braking can
only occur if a vehicle ahead is
detected, indicated by the vehicle
ahead indicator A 3 192.
If equipped only with front camera the
system operates up to a speed of 37
mph.
Below a speed of 25 mph the system
can apply full braking.
Emergency automatic braking may
slow the vehicle to a complete stop to
try to avoid a potential crash. If this
happens, emergency automatic
braking may engage the electric
parking brake to hold the vehicle at a
stop. To release press the electric
parking brake button or firmly press
the accelerator pedal.9 Warning
Emergency automatic braking is
an emergency crash preparation
feature and is not designed to
avoid crashes. Do not rely on the
system to brake the vehicle.
Emergency automatic braking will
Driving and operating197not brake outside of its operating
speed range and only responds to
detected vehicles.
Forward looking brake assist
In addition to the brake preparation
system and emergency automatic
braking, the forward looking brake
assist function makes the brake assist more sensitive. Therefore, pressing
the brake pedal less strongly results
in immediate hard braking. This
function helps the driver brake
quicker and harder before the
imminent collision.
If equipped only with front camera the system operates up to a speed of 53
mph.
9 Warning
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 for 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 wearingtheir 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.
Deactivation
On vehicles with front camera active
emergency braking can be
deactivated by repeatedly pressing
the gap switch V to Off setting,
198Driving and operating3 192. If deactivated a message is
displayed in the Driver Information
Centre.
On vehicles with radar sensor the
system can be disabled in the
personalisation menu in the Info-
display, 3 124.
System limitations In some cases, the active emergencybraking 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.Emergency automatic braking may
not:
● detect a vehicle ahead on winding or hilly roads.
● detect all vehicles, especially vehicles with a trailer, tractors,
muddy vehicles, etc.
● detect a vehicle when weather limits visibility, such as in fog,rain, or snow.
To avoid malfunction keep the areas
of the camera sensor in the
windscreen and the radar sensor in
the radiator grille always clean from
dirt, dust, ice and snow.
Complete attention is always required
while driving, and you should be
ready to take action and apply the
brakes and/or steer the vehicle to
avoid crashes.
Fault
In case the system requires a service,
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 3 122.
Parking assist
General information When the trailer hitch is attached,
change the configuration settings in
the vehicle personalisation menu in
the Info-Display. Vehicle
personalisation 3 124.
When attaching a trailer or bike
carrier to the trailer hitch, the parking
assist is deactivated.
Rear parking assist9 Warning
It is the driver who bears full
responsibility for the parking
manoeuvre.
Always check the surrounding
area while reversing and using the rear parking assist system.
Driving and operating199The rear parking assist makes
parking easier by measuring the
distance between the vehicle and
rear obstacles. It informs and warns
the driver by giving acoustic signals
and display indication.
The system has four ultrasonic
parking sensors in the rear bumper.
Activation
After ignition is switched on, the rear
parking assist is activated.
An illuminated LED in the parking
assist button r indicates that the
system is ready to operate.
Indication
The system warns the driver with acoustic signals against potentially
hazardous obstacles behind the
vehicle in a distance range up to
50 cm while a forward gear is
engaged, or up to 1.5 metres while
reverse gear is engaged.
Depending on which side of the
vehicle is closer to an obstacle, you
will hear acoustic warning signals in the vehicle on the respective side.
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
obstacles is displayed by changing
distance lines in the Driver
Information Centre 3 114.
The distance indication can be
inhibited by vehicle messages with a
higher priority. After dismissing the
message distance indication appears again.Deactivation
Press parking assist button r to
deactivate, the LED in the button
extinguishes.
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, the LED
in the button flashes for
three seconds and then extinguishes. A message is indicated in the Driver
Information Centre.
200Driving and operatingFront-rear parking assist9Warning
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 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 system has four ultrasonic
parking sensors each in the rear and front bumper.
Activation
The system is activated automatically
at a speed up to 7 mph.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 15 mph beforehand,
parking assist will be reactivated when speed drops below 7 mph.
When the system is deactivated, the
LED in the button extinguishes and
Park Assist Off pops-up in the Driver
Information Centre.
Driving and operating201Indication
The system warns the driver with
acoustic signals against potentially
hazardous obstacles in front of the
vehicle in a distance range up to
80 cm and against potentially
hazardous obstacles behind the
vehicle in a distance range up to
50 cm while a forward gear is
engaged, or up to 1.5 m while reverse
gear is engaged.
Depending on which side of the
vehicle is closer to an obstacle, you
will hear acoustic warning signals in the vehicle on the respective side.
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 3 114 or,
depending on the version, on the Info- Display 3 120.
The distance indication can be
inhibited by vehicle messages with a
higher priority. After dismissing the
message distance indication appears again.
Deactivation
The system is deactivated
automatically when vehicle speed
exceeds 7 mph.
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
during the ignition cycle or until
activation in personalisation menu
again. Vehicle personalisation 3 124.
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 3 122.