206Driving and operatingOnce the system is activated,
adaptive cruise control decelerates or
brakes if it detects a vehicle ahead,
which is slower or closer than the
desired following distance.9 Warning
Accelerating by the driver
deactivates automatic braking by
the system. This is indicated as a
pop-up warning in the Driver
Information Centre or by the
adaptive cruise control symbol
turning blue.
Indication on Driver Assistance page
As long as the set speed is
overridden, the bars in front of the
vehicle symbol appear blue.
Increase or reduce speed The preset speed can be changed by
moving thumb wheel to RES/+ to
increase or SET/- to decrease the
speed. Move thumb wheel repeatedly to change speed in small steps, move
and hold to change speed in large
steps.
Resume stored speed
If the system is switched on but
inactive and a speed was stored
before, move thumb wheel to RES/+
at a speed above 5 km/h (with
automatic transmission) or above 30
km/h (with manual transmission) to
resume the stored speed.Full speed range adaptive cruise
control on vehicles with automatic transmission
Full speed range adaptive cruise control will maintain a following
distance behind a detected vehicle
and slow your vehicle to a stop behind
that vehicle.
When the vehicle ahead accelerates
after a brief stop, the adaptive cruise
control will drive off automatically
without driver action. If necessary,
press RES/+ or the accelerator pedal
to resume adaptive cruise control.
Pressing the accelerator pedal allows
more control over the acceleration
after driving off. Note that automatic
braking is disabled during usage of
the accelerator pedal.
If the stopped vehicle ahead stands
for a longer time and then begins to
move forward, the green illuminated
vehicle ahead control indicator A will
flash and a warning chime will sound
as a reminder to check traffic before
resuming.
Driving and operating2079Warning
When full speed range adaptive
cruise control is deactivated or
cancelled, the vehicle will no
longer be held at a stop and can
start moving. Always be prepared
to manually apply the brake pedal
to hold the vehicle stationary.
Do not leave the vehicle while it is being held at a stop by the full
speed range adaptive cruise
control. Always move selector
lever to park position P and switch
off the ignition before leaving the
vehicle.
Setting the following distance
When adaptive cruise control detects a slower moving vehicle in the drivingpath, it will adjust the vehicle speed to
maintain the following distance
selected by the driver.
The following distance can be set to
near, medium or far.
Press K, the current setting is shown
in the Driver Information Centre.
Press K again to change the
following distance. The setting is also
displayed in the Driver Information
Centre.The selected following distance is
indicated by filled distance bars in the adaptive cruise control page.
Note that the following distance
setting is shared with the sensitivity
setting of forward collision alert
3 214.
Example: If setting 3 (far) is selected,
then the driver is warned sooner
before a possible collision, also if
adaptive cruise control is inactive or
switched off.
208Driving and operating9Warning
The Driver accepts full
responsibility to drive with the
appropriate following distance
based on traffic, weather, visibility and regional regulation. Followingdistance must be adjusted or the
system switched off when required by the prevailing conditions.
Indication on Driver Assistance page
Adaptive cruise control in Sport
mode
On vehicles with Flex Ride driving
modes, the driver can slightly
increase the Adaptive cruise control
acceleration when Sport mode is
selected. This function can be
deactivated in the Flex Ride
visualisation menu 3 199
Detecting the vehicle ahead
The green illuminated vehicle ahead
control indicator A is displayed when
the system detects a vehicle in the driving path. The range of the sensors
is between 25 and 150 metres
depending on vehicle speed.
Forward collision alert 3 214.
If this symbol does not display, or
displays briefly, adaptive cruise
control will not respond to vehicles ahead.
210Driving and operatingThe 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 mountainroads, 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
Driving and operating211lose 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.
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.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.
Hill considerations
9 Warning
Do not use adaptive cruise control
on steep hill roads.
212Driving and operatingSystem 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.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 3 122.
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 3 238.
Note
Perform updates of your
navigational maps regularly and
make sure that the correct SD-card
is inserted in the navigation map
card port.
Driving and operating215
Simultaneously a warning chime
sounds. Depress the brake pedal and
steer the vehicle, if it is required by the
situation.
Indication on Driver Assistance page
A symbol of a preceding vehicle
appears in grey when a vehicle was
detected.
The symbol turns amber when the
distance gets too small.
The symbol turns red if a collision is
imminent.
Selecting the alert sensitivity Press K 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 awaythe alert will occur. Consider traffic
and weather conditions when
selecting the alert timing.
216Driving 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.
Indication on Driver Assistance page
Deactivation
The system can be deactivated in the
personalisation menu, 3 124.
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.