186Driving and operating
■ Electronic Stability Control isoperating,
■ there is no traffic and nothing detected on the road sides for
several minutes. In this case there 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,
■ 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 button 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.
Driver'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.
188Driving and operating
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 3 130.
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
Vehicle messages 3 123.
Forward collision alert The forward collision alert can help to
avoid or reduce the damage caused
by front-end crashes. If a vehicle
directly ahead is approached too
quickly, a warning chime and alert in
the Driver Information Centre is
provided.
The green illuminated vehicle ahead
symbol A appears in the
speedometer when the system has
detected a vehicle in the driving path. A precondition is that forward collision
alert is activated in the vehicle
personalisation menu 3 130 or that it
is not deactivated by the button V
(depending on the system, see
following).
Depending on the vehicle's
equipment, there are two variants of
the forward collision alert available:
■ Forward collision alert based on
radar system
on vehicles equipped with adaptive cruise control 3 182.
■ 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 collisionpreparation setting is not deactivated
in the vehicle personalisation menu 3 130.
Selecting the alert sensitivity
The alert sensitivity can be set to
near, medium or far.
Press button E; the current setting is
shown in 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.
190Driving and operating
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
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.
SettingsSettings can be changed in the Auto
collision preparation menu in the
vehicle personalisation 3 130.
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 40 km/h, if it is
not deactivated by button V, see
below.
Selecting the alert sensitivity
The alert sensitivity can be set to
near, medium or far.
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.
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
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.
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.