Page 177 of 279

Driving and operating175
Activation of the functionality by
setting the speed
The adaptive cruise control has to be
switched on manually at a speed
between 30 km/h and 180 km/h.
For vehicles with automatic
transmission, the automatic selector
lever must be in position D or M.
Accelerate to the desired speed and
move the thumb wheel to SET/-. The
current speed is stored and
maintained.The speed value is indicated in the
Driver Information Centre.
When the adaptive cruise control is
operating, the stop-start system is
automatically deactivated.
Overriding set speedIt is always possible to drive fasterthan the selected set speed by
depressing the accelerator pedal.
When the accelerator pedal is
released, the vehicle returns to the
stored speed. If a slower moving
vehicle is ahead, the following
distance selected by the driver is
restored.
If the set speed is exceeded, the
indicated speed setting flashes in the Driver Information Centre and a
warning message appears.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.
Increasing speed
With the adaptive cruise control
active, hold the thumb wheel moved
to RES/+ or briefly move to RES/+
repeatedly: The speed increases continuously or in small increments.
Reducing speed
With the adaptive cruise control
active, hold the thumb wheel moved
to SET/- or briefly move to SET/-
repeatedly: The speed decreases
continuously or in small increments.
Page 178 of 279

176Driving and operatingResuming stored speed
Move the thumb wheel to RES/+ at a
speed above 30 km/h. The adaptive
cruise control is activated with the
stored set speed.
Taking over the speed limit from
the traffic sign assistant
The intelligent speed adaptation
informs the driver when a speed limit
is detected by the traffic sign
assistant. The detected speed limit
can be taken over as new set speed
for the adaptive cruise control.
With the camera at the top of the
windscreen, this system detects and
reads speed limit and end of speed
limit signs. The system also takes
account of information on speed limits from the navigation map data.
The function can be activated or deactivated in the personalisation
menu 3 119.
If the adaptive cruise control is active, the recognised speed limit will be
displayed in the Driver Information
Centre and MEM illuminates.In the Driver Information Centre,
speed limit sign is shown in the
display and MEM illuminates for a few
seconds.
Press MEM on the steering wheel to
request saving of the suggested
speed.
Press MEM on the steering wheel
once more to confirm and save the
new speed setting.
This speed limit is now the new set
speed of the adaptive cruise control.
Adaptive cruise control on
vehicles with automatic
transmission
For vehicles with automatic
transmission, adaptive cruise control
allows to maintain the selected
distance behind a stopping vehicle until a complete stop is reached.
If the system has stopped your
vehicle behind another vehicle, then
the set speed is replaced by a green
control indicator .. This symbol
notifies, that the vehicle is hold
automatically in stop position.If the stopped vehicle ahead was stopped for a longer time and then
begins to move forward, the green
illuminated vehicle ahead control
indicator . will flash and a warning
chime will sound as a reminder to check traffic before resuming.
When the vehicle ahead drives away,
press the accelerator pedal until
30 km/h and then move the thumb
wheel to SET- or RES+ to resume
adaptive cruise control. If the vehicle
stays stopped for more than five
minutes or if the driver's door is
opened and the driver's seat belt is
unfastened, then the electric parking
brake is applied automatically to hold
the vehicle. Control indicator m will
illuminate. To release electric parking
brake, press the accelerator pedal.
Electric parking brake 3 161.9 Warning
When the system is deactivated or
cancelled, the vehicle will no
longer be held at a stop and can
Page 179 of 279

Driving and operating177start moving. Be always prepared
to manually apply the brake to hold the vehicle stationary.
Do not leave the vehicle while it is
being held at a stop by 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 driving path, it will adjust the vehicle speed tomaintain the following distance
selected by the driver.
The following distance can be set to
close (1 bar), normal (2 bars) or far (3
bars).
If the engine is running and the
adaptive cruise control is enabled
(grey), you can modify the following
distance setting:
Press Ö, the current setting is shown
in the Driver Information Centre.
Press Ö again to change the following
distance: The new setting is
displayed in the Driver Information
Centre.
The selected following distance is
indicated by full bars in the adaptive
cruise control page.9 Warning
The driver accepts full
responsibility for the appropriate
following distance based on traffic, weather and visibility conditions.
Following distance must be
adjusted or the system switched
off when required by the prevailing
conditions.
Detecting the vehicle ahead
If the system detects a vehicle in the
driving path, the adaptive cruise
control symbol displayed in the Driver
Information Centre changes: - is
changed to w.
Deactivation of the functionality
Press Ñ, the adaptive cruise control
is in pause mode and a message is
displayed. The vehicle is driven
without adaptive cruise control.
The adaptive cruise control is
deactivated, but not disabled. The
last stored set speed remains in
memory for later usage.
The adaptive cruise control is
deactivated automatically when:
● The brake pedal is depressed.
● The vehicle accelerates above 180 km/h or slows down below
30 km/h.
Page 180 of 279

178Driving and operating● The electric parking brake isapplied.
● The Traction Control system or Electronic Stability Control is
deactivated or operating.
● The selector lever of automatic transmissions is neither in D nor
in M.
● A fault is detected in the Electronic Stability Control.
Switching off the system
Press C, the adaptive cruise control
mode is disabled and the adaptive
cruise control indication extinguishes
in the Driver Information Centre.
Pressing ß to activate the speed
limiter deactivates adaptive cruise
control.
Switching off the ignition deletes the
stored set speed.
Driver's attention ● Use the 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 the system when the spare wheel is in use.
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.
● The adaptive cruise control does ignore the oncoming traffic.
● The adaptive cruise control does not consider pedestrians and
animals for braking and driving
off.
● The adaptive cruise control considers stopped vehicles only
at low speed.
● Do not use the adaptive cruise control when towing a trailer.
● Do not use the 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. If it no
Page 181 of 279

Driving and operating179longer 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 while 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.
Hill considerations9 Warning
Do not use the 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. On steep hills,
you may have to use the accelerator
pedal to maintain your vehicle speed.
When going downhill you may have to brake to maintain or reduce your
speed.
Note that applying the brake
deactivates the system.
Page 182 of 279

180Driving and operatingFault
In the event of a fault with the adaptive
cruise control, you are alerted by the
illumination of a warning light and the display of a message in the
instrument panel, accompanied by an
audible signal.
The adaptive cruise control may not
operate correctly if traffic signs do not comply with the Vienna Convention
on Road Signs and Signals.
Have the system checked by a dealer
or a qualified workshop.
As a safety measure, do not use the
system if the brake lights are faulty.
Forward collision alert The forward collision alert may help toavoid or reduce the harm caused by
front-end crashes.
The forward collision alert uses the front camera in the windscreen to
detect a preceding vehicle directly
ahead, in your path.If a vehicle directly ahead is
approached too quickly, a warning
chime and alert in the Driver
Information Centre is provided.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.
Activation
Forward collision alert detects
vehicles and operates automatically
at all speeds between 5 km/h and 85 km/h. The system detects
stationary vehicles if the speed does
not exceed 80 km/h.
Alerting the driver The driver is warned by following
alerts:
● Symbol , illuminates and a
warning message is displayed in
the Driver Information Centre
when the distance to the vehicle
ahead gets to small.
● Symbol , illuminates, a warning
message is displayed in the
Driver Information Centre and a
warning chime sounds, when a
collision is imminent and
immediate driver's action is
required.
Page 183 of 279

Driving and operating1819Warning
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.
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.
Selecting the alert sensitivity
The alert sensitivity has to be set to
close, normal or distant in the vehicle personalisation menu 3 119.
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.
Deactivation The system can only be deactivated
by deactivating the active emergency
braking in the vehicle personalisation
3 119.
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
● driving during nighttime
● weather limits visibility, such as fog, rain, or snow
● the sensor in the windscreen is blocked by snow, ice, slush, mud,dirt etc.
● the windscreen is damaged or affected by foreign objects, e.g.
stickers
Active emergency braking
Active emergency braking can help to reduce the damage and injury from
crashes with vehicles, pedestrians
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 3 180 or the front pedestrian
protection alert 3 184.
Page 184 of 279

182Driving and operatingThe feature uses various inputs (e.g.
camera 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 to
animals. After a sudden lane
change, the system needs a
certain time to detect the next
preceding vehicle.
The driver must always be ready
to take action and apply the brakes and steer to avoid collisions.
Operation conditions
Active emergency braking is
equipped with a front camera and
operates in forward gear above
walking speed up to 85 km/h. The
system detects stationary vehicles
only if the speed does not exceed
80 km/h.
Activation A precondition is that forward collision
alert with front camera system is not
deactivated in the vehicle
personalisation menu 3 119.
Functionality The system includes: ● emergency automatic braking
● forward looking brake assist ● forward collision alert
● front pedestrian protection
Emergency automatic braking
After activation of brake preparation
system and just before the imminent
collision, this function automatically
applies limited braking to reduce theimpact speed of the collision or
prohibit a crash. If active emergency
braking is applied, m flashes in the
instrument cluster. Depending on the
situation, the vehicle may
automatically brake moderately or
hard. This front automatic braking can
only occur if a vehicle 3 180 or a
pedestrian 3 184 ahead is detected.
Emergency automatic braking may slow the vehicle to a complete stop to
try to avoid a potential crash.
● Automatic transmission: If the vehicle comes to a complete
stop, automatic braking is
maintained for up to two
seconds. Keep the brake pedal
depressed to prevent the vehicle
from starting off again.
● Manual transmission: If the vehicle comes to a complete
stop, the engine may stall.
Operation of the function may be felt
by a slight vibration in the brake
pedal.