188Driving and operating
Hill and trailer considerations
System performance on hills and
when towing a trailer depends on your
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, 3 132.
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.
190Driving and operating
Press button E; the current setting is
shown on the Driver Information
Centre. Press button 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.
Alerting the driver
A green illuminated vehicle ahead
control indicator A lights up 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.
192Driving and operating
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.
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 to
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, e.g. 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 in
seconds, displayed on a page in the
Driver Information Centre 3 119.
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.
Driving and operating193
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 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
3 132.
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
194Driving and operating
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
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, 3 132.
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 do, vehicle messages are
displayed in the Driver Information
Centre.
Vehicle messages 3 126.
196Driving and operating
The front parking assist can also be
activated at a low speed by pressing
the parking assist button r or 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 handicaps 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 3 119.
On version with Uplevel-Display, the
distance to a front obstacle is
indicated by changing segments.
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 by vehicle messages
with a higher priority. Once the
distance indication was overwritten by a vehicle message, distance is no
more indicated until parking assist is
activated again.
Deactivation
Deactivate the system by pressing
the parking assist button r or D
briefly.
The LED in the button extinguishes
and Park Assist Off will be displayed
in the Driver Information Centre.
The system is deactivated
automatically when exceeding a
certain speed.
If the r or D button is pressed
once within an ignition cycle, the front
parking assist is always reactivated
when the vehicle speed goes below a certain value.
Driving and operating197
FaultIn the event of a fault in the system,
r illuminates or a message is
displayed in the Driver Information
Centre.
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.
Vehicle messages 3 126.9 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.
Objects 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.
Notice
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.
Notice
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.
200Driving and operating
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.
Changing the parking side
The system is configured to detect parking slots on the passenger side.
To detect parking slots on the driver
side, switch turn indicator to the driver
side.
Display priorities
After activating the advanced parking assist, a message appears on the
Driver Information Centre. Indication
of messages with higher priority like
vehicle messages 3 126 will be
displayed. After approving the
message by pressing the SET/CLR
button, parking assist messages
appear again and parking can be
continued.
Deactivation
The system is deactivated by:
■ pushing button D for approx.
one second
■ parking manoeuvre successfully ended
■ driving faster than 18 mph
■ switching off the ignition
Deactivation by the driver or by the
system during manoeuvring will be indicated by Parking Deactivated in
the Driver Information Centre.
Fault A message appears in the Driver
Information Centre when:
■ there is a fault in the system
■ the driver did not successfully complete the parking manoeuvre
■ the system is not operationalIf an object is detected during parking instructions, Stop is indicated in the
Driver Information Centre. Removing
the object will resume the parking
manoeuvre. If the object is not
removed, the system will be
deactivated. Push button D for
approx. one second to activate the
system and search for a new parking
slot.
Important hints for using the
parking assist systems9 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.