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Driving and operating191The system is also automatically
deactivated when:
● Vehicle speed accelerates above
190 km/h or slows down below
25 km/h . Vehicles with automatic
transmission slows down to a
stop without deactivating within
5 minutes.
● The Traction Control system is deactivated or operating.
● The Electronic Stability Control is
deactivated or operating.
● There is no traffic and nothing detected on the road sides for
approx. 1 minute. In this case
there are no radar echoes and
the sensor may report that it is
blocked.
● The active emergency braking system is applying the brakes.
● Driving on steep inclines.
● The radar sensor is blocked by an ice or water film.
● A fault is detected in the radar, camera, engine or brake system.
● The brakes need to cool down.Additionally, the system is
automatically deactivated on vehicles
with automatic transmission (full
speed range adaptive cruise control)
when:
● The incline uphill or downhill is greater than 20%.
● The electric parking brake is applied.
● 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.The stored speed is indicated in
brackets in the Driver Information
Centre when the system is
deactivated but not switched off.
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.
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192Driving and operatingDriver'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.
● 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 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
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.
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Driving and operating193If 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 considerations9 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.
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194Driving and operatingRadar unit
The radar unit is mounted behind the
radiator grille 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 3 123.
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 3 220.
Note
Perform updates of your
navigational maps regularly and
make sure that the correct SD-card
is inserted in the navigation map
card port.
Note
Speed limit signs which are
combined with add-on signs, e.g.
time, weather or vehicle type
limitations, are not considered by
this system.
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Driving and operating195Note
The driver stays fully responsible for
driving conform to speed limits and
has to supervise any automatic set
speed change performed by this
system.
Due to system limitations and
latencies, the set speed might be
changed after entering the road
section with the new speed limit.
Speed limit signs between 30 km/h
and 150 km/h are considered.
Switching on the system
The function can be activated or
deactivated in the vehicle settings
menu of the Driver Information Centre
3 112. Furthermore, adaptive cruise
control has be to switched on as
described above.Usage
Even if adaptive cruise control is
inactive, the set speed is updated
automatically at each new detected
speed limit as described in the next
section. Press RES+ to re-activate
adaptive cruise control, using the
memorised set speed.
Note
Adaptive cruise control has to be
initiated once by pressing SET- after
ignition or just adaptive cruise
control has been is switched on.
If adaptive cruise control is active, the detected speed limit will be displayed in the Driver Information Centre. The
driver can accept or decline the
detected new set speed while the
display message is shown.
Press SET- on the steering wheel to
accept the detected speed limit and
take over as new set speed.
Press RES+ to decline detected
speed limit and keep the current set
speed.
If no action is performed when the
message is displayed, the detected
speed limit is taken over as new set
speed automatically after 3 seconds.
The message disappears and is
followed by the offset message:
If a new set speed was defined, a
confirmation message is displayed.
During this time, the offset from the
set speed can be adjusted.
Press SET- or RES+ to adjust the
offset.
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196Driving and operatingIf no action is performed while the
message is displayed, the last set offset will be used and the message
disappears after 3 seconds.
The new set speed including offset is displayed in the Driver Information
Centre.
System limitations
Intelligent adaptive cruise control has
the same limitations as the traffic sign assistant 3 220.
Implicit speed limits may be
considered with a delay, e.g. city entry, city exit, or motorway entry
signs.
The system may ignore a particular
traffic sign or use a wrong speed limit.
A new speed limit from the navigation may be taken over automatically after
a certain distance since the last
detected traffic sign or when entering
a new road segment, e.g. road exits
or round-abouts.Forward collision alert
The forward collision alert is part of
the forward collision system 3 124. It
can help to avoid or reduce the harm
caused by front-end crashes.
A vehicle ahead is indicated by the
control indicator A.
Additionally, the status of the forward
collision alert is indicated on the
Driver Assistance page in the Driver
Information Center 3 112.
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
and front camera to detect a vehicle
directly ahead, in your path.
Forward collision alert with front
camera detects vehicles to distances
of approx. 60 m and operates
automatically at all speeds above
walking speed.Forward collision alert with radar
sensor detects vehicles to distances
of approx. 150 m and operates
automatically at all speeds above
walking speed.
Activation
A precondition is that forward collision
alert in the vehicle personalisation
menu is not deactivated 3 124.
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. On
vehicles with head-up display, A is
projected on the windscreen.
The control indicator A changes to
amber when the distance to a
preceding moving vehicle gets too
small.Caution
The colour lighting of this control
indicator does not correspond to
local traffic laws on following
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Driving and operating197distance. 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 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 flashing red
LED stripe or the pop-up symbol in
the head-up display which is
projected on the windscreen in the
driver's field of view.
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.
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198Driving and operating
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.
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.