Page 193 of 299
Driving and operating191
Press button V; the current setting is
shown in the Driver Information
Centre. Press button V again to
change the alert sensitivity.
Alerting the driver
When approaching another vehicle
too rapidly, the collision alert warning page will be indicated in the Driver
Information Centre. Simultaneously a
warning chime sounds. Depress the
brake pedal, if it is required by the situation.
Deactivation
The system can be deactivated.
Press button 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.
Page 194 of 299

192Driving and operatingThe 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 on
other 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 path. It is active at speeds above 40 km/h.
When a preceding vehicle is detected
ahead, the distance is indicated in
seconds, displayed on a page in the
Driver Information Centre 3 117.
Press the MENU button 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 3 189.
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
3 130.
Page 195 of 299

Driving and operating193
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
results immediately in a strong
braking. This function helps the driver brake quicker and stronger before theimminent 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
Page 196 of 299

194Driving and operating
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, 3 130.
Fault
In the event of a system service
requirement, a message is displayed
in the Driver Information Centre.If the system does not work as it
should, vehicle messages are
displayed in the Driver Information
Centre.
Vehicle messages 3 123.
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 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.
Control indicator r 3 113.
Page 197 of 299

Driving and operating195
Button D
Parking assist is activated and deactivated by pressing the parking assist button D. If the vehicle is
equipped with parking assist and
advanced parking assist 3 197 both
use the same button to operate the
systems.
For activating or deactivating parking
assist, press button D once briefly.
For activating or deactivating
advanced parking assist, press
button D for approx. one second.
If one system is active, it is possible
to switch between both systems by
pressing the button shorter or longer.Activation
When reverse gear is engaged, the
system is activated automatically.
The front parking assist can also be activated at a low speed by pressing
the parking assist button D briefly.
An illuminated LED in the parking
assist button indicates that the
system is ready to operate.
Indication The system warns the driver withacoustic signals against obstacles in
front of or behind the vehicle.
Depending on which of the sensors
are closer to an obstacle, you will hear a buzzing sound of the respective
sensors. The interval between the
sounds becomes shorter as the
vehicle gets closer to the obstacle.
When the distance is less than
30 cm, the buzzing is continuous.
Additionally, the distance to obstacles
can be shown in the Driver
Information Centre (DIC) 3 117.
On version with Uplevel-Display, the
distance to a front obstacle is
indicated by changing segments.
Page 198 of 299

196Driving and operating
On version with Uplevel-Combi-
Display, the distance to a front and
rear obstacle is indicated by changing distance lines around the vehicle.
The distance indication in the display
can be inhibited and overwritten by
vehicle messages with a higher
priority. Once the distance indication
is overwritten by a vehicle message,
distance is no longer indicated until
parking assist is activated again.
Deactivation
Deactivate the system by pressing
the parking assist button D briefly.
The LED in the button extinguishes
and Park Assist Off will be displayed
in the Driver Information Centre
(DIC).
The system is deactivated
automatically when exceeding a
certain speed.
If button D is pressed once within an
ignition cycle, the front parking assist
is always reactivated when the
vehicle speed goes below a certain
value.
Fault
In the event of a fault in the system,
r illuminates or a message is
displayed in the Driver Information
Centre (DIC).
If the system does not work due to temporary conditions like snow
covered sensors, r illuminates or a
message is displayed in the Driver
Information Centre (DIC).
Vehicle messages 3 123.9 Warning
Under certain circumstances,
various reflective surfaces on
objects or clothing as well as
external noise sources may cause the system to fail to detect
obstacles.
Special attention has to be paid to
low obstacles which can damage
the lower part of the bumper.
Caution
Performance of the sensor can be reduced when sensors are
covered, e.g. by ice or snow.
Performance of the parking assist
system can be reduced due to
heavy loading.
Special conditions apply if there
are taller vehicles involved (e.g.
off-road vehicles, mini vans,
vans). Object identification in the
upper part of these vehicles
cannot be guaranteed.
Page 199 of 299

Driving and operating197Objects with a very small reflection
cross section, like objects of
narrow size or soft materials, may
not be detected by the system.
Parking assist will not detect
objects out of the detection range.
Note
The parking assist system
automatically detects factory-fitted
towing equipment. It is deactivated
when the connector is plugged in.
The sensor may detect a non-
existing object (echo disturbance)
caused by external acoustical or
mechanic disturbances.
Note
If engaging a forward gear and
exceeding a certain speed, the rear
parking assist will be deactivated
when the rear carrier system is
extended.
If engaging reverse at first, the
parking assist will detect the rear
carrier system and provide a buzzing
sound. Press r or D briefly to
deactivate the parking assist.
Advanced 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 advanced parking assist system manoeuvres the driver into a parking
slot by giving instructions on the
Driver Information Centre and
acoustic signals.
The system uses the sensors of the
parking assist system in combination
with two additional sensors on both
sides of the front bumper and the rear
bumper.
Button D
Advanced parking assist and parking
assist 3 194 both use the same button
to operate the systems. For activating or deactivating parking assist press
button once briefly. For activating or
deactivating advanced parking assist
press button D for approx.
one second.
If one system is active, it can be
switched between both systems by
pressing the button shorter or longer.
Page 200 of 299

198Driving and operating
Activation
When looking for a parking slot, the
system has to be activated by
pressing the button D for approx.
one second.
The system can only be activated at
a speed up to 30 km/h and the system searches for a parking slot at a speed
up to 30 km/h.
The maximum allowed parallel
distance between the vehicle and a
row of parking cars is 1.8 metres.
Functionality
When the vehicle passes a row of
cars and the system is activated, the
advanced parking assist system
begins looking for a suitable parking
slot. When a suitable slot is detected, a visual feedback on the Driver
Information Centre and an acoustic
signal are given.
If the driver does not stop the vehicle
within 10 metres after a parking slot is
proposed, the system starts to search for another suitable parking slot.
The parking slot suggestion of the
system is accepted when the vehicle
is stopped by the driver within
10 metres after the Stop message is
given. The system calculates the
optimal route into the parking slot.
Then it manoeuvres the driver into the
slot by giving detailed instructions.