Driving and operating183
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
desired distance if a slower vehicle is
ahead. Otherwise it returns to the
stored speed.
Once 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.
Increase speed
With adaptive cruise control active,
hold thumb wheel turned to RES/+:
speed increases continuously in large
increments, or activate RES/+
repeatedly: speed increases in small increments.
With adaptive cruise control active, if
the vehicle is driven much faster than the desired speed, e.g. after
depressing the accelerator pedal,
then the current speed can be stored
and maintained by turning the thumb
wheel to SET/-.
Reduce speed With adaptive cruise control active,hold thumb wheel turned to SET/-:
speed decreases continuously in
large increments, or activate SET/-
repeatedly: speed decreases in small
increments.
With adaptive cruise control active, if
the vehicle is driven much slower than
the desired speed, e.g. because of a
slower vehicle ahead, then the
current speed can be stored and
maintained by turning the thumb
wheel to SET/-.
Resume stored speed
If the system is switched on but
inactive, then turn thumb wheel to
RES/+ at a speed above 30 mph to
resume the stored speed.
Setting the following distance
When adaptive cruise control detects a slower moving vehicle in the driving
path, 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.
Driving and operating185The 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 deactivatedby 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.● Electronic Stability Control is operating.
● There is no traffic and nothing detected on the road sides forseveral minutes. In this casethere are no radar echoes and
the sensor may report that it is
blocked.
● Collision imminent braking system is applying the brakes.
● Radar sensor is blocked by an ice
or water film.
● A fault is detected in the radar, engine or brake system.
When adaptive cruise control is
deactivated automatically, the control indicator m illuminates white and a
warning symbol is displayed as a pop-
up in the Driver Information Centre.
The stored speed is maintained.
9 Warning
When adaptive cruise control is
deactivated, the driver must take
over full brake and engine control.
Switching off
Press C to switch off adaptive cruise
control. The control indicator m
extinguishes. The stored speed is
deleted.
Switching off the ignition also
switches off adaptive cruise control
and deletes the stored speed.
186Driving and operatingDriver's attention● Use adaptive cruise control carefully on bends or mountain
roads, as it can lose the vehicle
ahead and require 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.
● 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 completely suppresses the
visibility. In case of sensor
blockage, clean the sensor
cover.
System limits ● 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 todetect 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 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
Driving and operating189on vehicles equipped with
adaptive cruise control 3 181.
● Forward collision alert based on
front camera system
on vehicles with traditional cruise
control or none 3 179.
Forward collision alert based on
radar system
The system uses the radar sensor
behind the radiator grille to detect a
vehicle directly ahead, in your path,
within a distance of max. 150 metres.
Activation
Forward collision alert operates
automatically above walking speed, provided that Auto collision
preparation setting is not deactivated
in the vehicle personalisation menu
3 129.
Selecting the alert sensitivity
The alert sensitivity can be set to
near, medium or far.
Press E; the current setting is shown
in the Driver Information Centre.
Press E again to change the alert
sensitivity. The setting is also
displayed in the top line of the Driver
Information Centre.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.
190Driving and operatingAlerting the driver
A green illuminated vehicle ahead
control indicator A illuminates in the
instrument cluster when the system has detected a vehicle in the driving
path. When the distance to a
preceding moving vehicle gets too
small or when approaching another
vehicle too rapidly and a collision is
imminent, the collision alert symbol
pops-up in the Driver Information
Centre. Simultaneously a warning
chime sounds.
Depress the brake pedal, if it is
required by the situation.
Settings
Settings can be changed in the Auto
collision preparation menu in the
vehicle personalisation 3 129.
Forward collision alert based on
front camera system
Forward collision alert uses the front
camera system in the windscreen to
detect a vehicle directly ahead, in
your path, within a distance of approx.
60 metres.
Activation
Forward collision alert operates
automatically above 25 mph, if it is not deactivated by pressing V, see
below.
Selecting the alert sensitivity
The alert sensitivity can be set to
near, medium or far.
Press V; the current setting is shown
in the Driver Information Centre.
Press V again to change the alert
sensitivity.
192Driving and operatingFollowing distanceindication
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 in
seconds, displayed on a page in the
Driver Information Centre 3 116.
Press MENU on the turn signal lever
to select Vehicle Information Menu
X and turn the adjuster wheel to
choose following distance indication
page.
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 3 188.
The feature uses various inputs (e.g.
radar sensor, brake pressure, vehicle speed) to calculate the probability of
a 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 assist9Warning
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.
Driving and operating193Brake preparation system
When approaching a vehicle ahead
so quickly that a collision is likely, the brake preparation system slightlypressurises 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
results immediately in a strong
braking. This function helps the driver
brake quicker and stronger before the imminent collision.9 Warning
Active emergency braking is not
designed to apply strong
autonomous braking or to avoid automatically a collision. It is
designed to reduce the vehicle
speed before collision. It may not
react on stopped vehicles,
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 wearing their seat belts.
System limitations
The active emergency braking has
limited or no function during rain,
snow or heavy dirt, as the radar
sensor can be covered by a water
film, dust, ice or snow. In case of
sensor blockage, clean the sensor
cover.
In some seldom cases the active
emergency braking system may
provide a short automatic braking in
situations that seem to be
unnecessary, for instance due to
traffic signs in a curve or due to
vehicles in another lane. This is
acceptable operation, the vehicle
does not need service. Firmly apply
the accelerator pedal to override the
automatic braking.
Settings
Settings can be changed in the Auto
collision preparation menu in the
vehicle personalisation, 3 129.
Fault
In the event of a system service
requirement, a message is displayed
in the Driver Information Centre.
Driving and operating195Parking assist button D and
operation logic
Front-rear parking assist is equipped
with D. If the vehicle is additionally
equipped with advanced parking
assist (see the following separate
description), both systems will be
operated by pressing 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.
Button logic to operate the systems is as follows:
● 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: short press 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 3 116.