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Driving and operating183●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.
On Midlevel display, the stored speed is indicated in brackets in the Driver
Information Centre when the system
is deactivated but not switched off.
On Uplevel display, 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.
Driver'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.
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184Driving and operating● Adaptive cruise control doesignore 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
camrea applies a certain correction
based on the detectable lane
markings. The control indicator A will
extinguish, if a vehicle ahead is no longer detected.
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. Furthermore,
adaptive cruise control was designed to brake as late as possible to allow
changing the lane before the
automatic braking. 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 while
driving fast or if the visibility is
reduced due to weather conditions.
While entering or exiting a motorway, adaptive cruise control may lose thevehicle ahead and accelerate up to
the set speed. For this reason,
decrease the set speed before the
exit or before the entry.
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Driving and operating185Vehicle 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.
Hill and trailer considerations
9 Warning
Do not use adaptive cruise control
on steep hill roads.
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. Full speed range
adaptive control is deactivated
automatically, as the vehicle is
stopping uphill on an incline greater than 10%. In this condition, be
prepared to take control of the
vehicle.
Note that applying the brake
deactivates the system.
Radar unitThe radar unit is mounted behind the
radiator grille behind or below the
brand emblem.
Number plate mounting 3 221.9 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
Settings can be changed in the
vehicle personalisation menu in the
Info Display.
Select the relevant setting in Settings
I Vehicle in the Info Display.
Info Display 3 120.
Vehicle personalisation 3 123.
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186Driving and operatingFault
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,
then a message is displayed in the
Driver Information Centre.
Vehicle messages 3 121.
Forward collision alert The forward collision alert may help toavoid or reduce the harm caused by
front-end crashes.
If the vehicle is equipped with
conventional cruise control, the
forward collision alert uses the front
camera in the windscreen to detect a
vehicle directly ahead, in your path.
If the vehicle is equipped with
adaptive cruise control, the forward
collision alert uses the radar sensor to detect a vehicle directly ahead, in
your path.
Number plate mounting 3 221
A vehicle ahead is indicated by the
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 with front camera system or
radar sensor is not deactivated in the vehicle personalisation menu 3 123.
Activation Forward collision alert with front
camera detects vehicles to distances
and operates automatically at all
speeds above walking speed.
Forward collision alert with radar
sensor detects vehicles to distances
and operates automatically at all
speeds above walking speed.
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.
The control indicator A changes to
yellow when the distance to a
preceding moving vehicle gets too
small or when approaching another
vehicle too rapidly.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.
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Driving and operating187When the time to a potential collision
with a vehicle in front gets too small
and a collision is imminent, the
collision alert symbol pops-up in the
Driver Information Centre and the
driver gets notified by a warning
chime sound.
Depress the brake pedal and steer the vehicle, if it is required by the
situation.
Selecting the alert sensitivity
Press V or E to set the alert
sensitivity to near, medium or far.The first button press shows the
current setting on the Driver
Information Centre. Additional button
presses will change this setting. The
chosen setting will remain until it is
changed. The alert timing will vary based on vehicle speed. The faster
the vehicle speed, the farther away
the alert will occur. Consider traffic
and weather conditions when
selecting the alert timing.
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 by the
personalisation menu 3 123.
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.
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188Driving and operatingThe 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 react
also 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 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 indicator
lever and turn the adjuster wheel to
choose following distance indication
page 3 114
On 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.
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Driving and operating189
If Adaptive cruise control is active,
this page shows the alert sensitivity
setting instead of following distance setting 3 178.
Active emergency braking Active emergency braking can help toreduce 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 3 186.
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
supplemental use only to reduce
the vehicle speed before a
collision.
The system may not react for
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 50 mph.
With radar sensor active emergency
braking operates in forward gear
above walking speed at all speeds.
Number plate mounting 3 221.
A precondition is that forward collision
alert is not deactivated in the vehicle
personalisation menu 3 123.
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
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.
If equipped only with front camera the
system operates up to a speed of
50 mph.
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190Driving and operatingEmergency 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 may
automatically brake moderately or
hard. This front automatic braking can
only occur if a vehicle ahead is
detected, indicated by the vehicle
ahead indicator A 3 186.
If equipped only with front camera the
system operates up to a speed of
50 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
not 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
52 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.