182Driving and operating
The selected following distance is
indicated by filled distance bars on
the adaptive cruise control page.
Note that the following distance
setting is shared with the sensitivity
setting of forward collision alert.
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.
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
The green illuminated "vehicle
ahead" control indicator A is
displayed in the speedometer when the system detects a vehicle in the
driving path.
If this symbol does not appear, or
appears briefly, adaptive cruise
control will not respond to vehicles
ahead.
Deactivation
Adaptive cruise control is deactivated by the driver when:
■ y is pressed.
■ Brake pedal is applied.
■ Clutch pedal is depressed for more
than four seconds.
■ Gear selector lever of automatic transmission is moved to N.
The system is also automatically
deactivated when:
■ Vehicle speed slows down below 28 mph or accelerates above
120 mph.
■ Traction Control system is operating for more than
20 seconds.
184Driving and operating
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 in
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.
Driving and operating185
Hill and trailer considerations
System performance on hills and
when towing a trailer 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, 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 3 129.
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.
Driving and operating189
Deactivation
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 onother 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, such as 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 lane.
It is active at speeds above 25 mph.
When a preceding vehicle is detected ahead, the distance is indicated inseconds, displayed on a page in the
Driver Information Centre 3 117.
Press MENU on the turn signal lever
to select Vehicle Information Menu
X and turn the adjuster wheel to
choose following distance indication
page.
190Driving and operating
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 3 186.
The feature uses various inputs (e.g.
radar sensor, brake pressure, vehicle speed) to calculate the probability ofa frontal collision.
Active emergency braking operates automatically above walking speed,
provided that Auto collision
preparation setting is not deactivated
in the vehicle personalisation menu 3 129.
The system includes: ■ brake preparation system
■ emergency automatic braking
■ forward looking brake assist9 Warning
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
192Driving and operatingParking assistFront-rear parking assist9 Warning
The driver bears full responsibility
for the parking manoeuvre.
Always check the surrounding
area when driving backwards or
forwards while using parking
assist system.
The front-rear parking assist
measures the distance between the vehicle and obstacles in front of and
behind the vehicle. The system gives acoustic signals and display
messages.
The system has four ultrasonic
parking sensors each in the rear and
front bumper.
It uses two different acoustic warning
signals for the front and rear
monitoring areas, each with a
different tone frequency. The signal
for front obstacles sounds via the
front speakers, for rear obstacles it
sounds from the rear of the vehicle.
Parking assist button D and
operation logic
Front-rear parking assist is equipped
with button D. If the vehicle is
additionally equipped with advanced parking assist (see the following
separate description), both systems
will be operated by button D.
Short press on D deactivates or
activates the front parking assist.
Long press on D (approx.
one second) activates or deactivates
the advanced parking assist.
Driving and operating193
Button logic operates the systems by
pressing as following:
■ Front-rear parking assist is active: short press deactivates front-rear
parking assist.
■ Front-rear parking assist is active: long press activates advanced
parking assist if a forward gear is engaged.
■ Advanced parking assist is active: short press activates front-rear
parking assist.
■ Advanced parking assist is active: long press deactivates advanced
parking assist.
■ Advanced parking assist and front- rear parking assist are active: shortpress deactivates both systems.
Activation
When reverse gear is engaged, the
front and rear parking assist is ready
to operate.
The front parking assist is also
activated automatically at a speed up to 7 mph.An illuminated LED in the parking
assist button indicates that the
system is ready to operate.
If the vehicle exceeds a speed of 7 mph, the front parking assist is
deactivated. The front parking assist
is always reactivated when vehicle
speed drops below 7 mph.
Indication
The system warns the driver with
acoustic signals against potentially
hazardous obstacles behind and in
front of the vehicle. Depending on
which side of the vehicle is closer to
an obstacle, you will hear acoustic warning signals on the respective
side of the vehicle. The interval
between the sounds becomes shorter
as the vehicle gets closer to that
obstacle. When the distance is less
than approx. 30 cm, the sound is
continuous.
Additionally, the distance to obstacles may be shown in the Driver
Information Centre 3 117.
The distance to a front and rear
obstacle is indicated by changing
distance lines around the vehicle.
Rear obstacles are indicated
acoustically and visually at the same
time.
Front obstacles are indicated visually
first. At distances less than 80 cm an
acoustic signal also sounds.
The distance indication in the Driver
Information Centre can be inhibited
by vehicle messages with a higher
priority. After approving the message
by pressing the SET/CLR button on
the turn signal lever, distance
indication appears again.
194Driving and operating
Deactivation
The rear parking assist automatically
switches off when reverse gear is
disengaged.
The front parking assist is deactivated
automatically at a speed above
7 mph.
Manual deactivation is possible by
pressing D briefly.
When the system is deactivated, the
LED in the button extinguishes.
Additionally, Park Assist Off pops-up
in the Driver Information Centre when the system is deactivated manually.
After a manual deactivation, the front
parking assist is activated again if
D is pressed or if reverse gear is
engaged.
Fault
In the event of a fault in the system or if the system does not work due to
temporary conditions, e.g. ice
covered sensors, control indicator
r illuminates or a message is
displayed in the Driver Information
Centre.
Vehicle messages 3 123.
Control indicator r 3 113.
Advanced parking assist9 Warning
The driver bears full responsibility
for accepting the parking slot
suggested by the system and the
parking manoeuvre.
Always check the surrounding
area in all directions when using
advanced parking assist.
The advanced parking assist system manoeuvres the driver into a parkingslot by giving instructions on the
Driver Information Centre and
acoustic signals. The driver must
control acceleration, braking, steering
and gear shifting.
The system uses the sensors of the
front-rear parking assist in
combination with two additional
sensors on both sides of the front and rear bumper.