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Driving and operating167● After a sudden lane change, thesystem 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 brake for stopped vehicles,
pedestrians or animals.
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. If it no
longer detects any vehicle ahead,
then control indicator A will
extinguish.
If the centrifugal force is too high in a bend, the system slows down the vehicle slightly. This braking level is
not designed to avoid spinning off the bend. The driver is responsible for
reducing the selected speed before
entering a bend and in general to
adapt the speed to the road type and
to existing speed limits.
Motorways
On motorways, adapt the set speed
to the situation and the weather.
Always consider that adaptive cruise
control has a limited visibility range, a
limited braking level and a certain
reaction time to verify if a vehicle is on
the driving path or not. Adaptive
cruise control may not be able to
brake the vehicle in time to avoid a
collision with a much slower vehicle or after a lane change. This is
particularly true if driving fast or if the
visibility is reduced due to weather
conditions.
While entering or exiting a motorway,
adaptive cruise control may lose the
vehicle ahead and accelerate up to
the set speed. For this reason,
decrease the set speed before the
exit or before the entry.
Vehicle path changes
If another vehicle enters your driving
path, adaptive cruise control will first
consider the vehicle when it is
completely in your path. Be ready to
take action and depress the brake
pedal, if you need to brake more
quickly.
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168Driving and operatingHill and trailer considerations
System performance on hills and
when towing a trailer depends on your
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, especially
when towing a trailer, 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 especially when towing a trailer.
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, after a frontal accident, 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 the Auto
collision preparation menu in the
vehicle personalisation, 3 105.
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.
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Driving and operating169Vehicle messages 3 99.
Forward collision alert The forward collision alert can help to
avoid or reduce the harm caused by
front-end crashes.
A vehicle ahead is indicated by a
control indicator A.
If a vehicle directly ahead is
approached too quickly, a warning
chime and alert in the Driver
Information Centre is provided.
A precondition is that forward collision
alert is activated in the vehicle
personalisation menu 3 105 or that it
is not deactivated by pressing V
(depending on the system, see
following).
Depending 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 3 162.
● Forward collision alert based on
front camera system
on vehicles with traditional cruise
control or none 3 159.
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 maximum distance of
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
3 105.
Selecting the alert sensitivity
The alert sensitivity can be set to
near, medium or far.
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170Driving and operating
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
A green illuminated vehicle ahead
control indicator A illuminates in the
instrument cluster when the system has detected a vehicle in the driving
path. 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. Simultaneously a warning
chime sounds.
Depress the brake pedal, if it is
required by the situation.
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Driving and operating171SettingsSettings can be changed in the Auto
collision preparation menu in the
vehicle personalisation 3 105.
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.
Alerting the driver
A green illuminated vehicle ahead
control indicator A illuminates in the
instrument cluster when the system has detected a vehicle in the driving
path.
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.
Simultaneously a warning chime
sounds. Depress the brake pedal, if it is required by the situation.
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172Driving and operatingDeactivation
The system can be deactivated.
Press V repeatedly until the following
message appears in the Driver
Information Centre.
General information for both
variants of forward collision alert
9 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 to
other 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, e.g.
fog, rain, or snow
● when the sensor is blocked by snow, ice, slush, mud, dirt, or
windscreen damage
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 93 . Press
MENU on the turn signal lever to
select Vehicle Information Menu
X and turn the adjuster wheel to
choose following distance indication
page.
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Driving and operating173
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.
Active Emergency Braking
Active emergency braking can help to reduce the damage 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 3 169.
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
3 105.
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.
Brake preparation system
When approaching a vehicle ahead
so quickly that a collision is likely, the
brake preparation system slightly
pressurises 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.
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174Driving and operating9Warning
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 Auto
collision preparation menu in the
vehicle personalisation, 3 105.
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 99.