194Driving 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.
Deactivation The system can be deactivated.
On forward collision alert with radar
sensor the system can be disabled by
the personalisation menu, 3 124.
On forward collision alert with front
camera press V repeatedly until
Forward Collision Alert Off appears in
the Driver Information Centre.
If the forward collision alert was
deactivated, alert sensitivity is set to
"medium" when ignition is switched on next time.
The last selected setting will be stored
when the ignition is switched off.
General information9 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
Forward collision alert is designed to warn on vehicles only, but may reactalso to other 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,
windscreen damage or affected
by foreign items, e.g. stickers
Following distance indication
The following distance indication
displays the distance to a preceding
moving vehicle. The front camera in
Driving and operating195the windscreen and the Radar sensor
are used to detect the distance of a
vehicle directly ahead in the vehicle's
path. 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.
On Midlevel display, choose Info
Menu ? via MENU on the turn
signal lever and turn the adjuster wheel to choose following distance
indication page, 3 114On Uplevel display, select Info menu
via steering wheel buttons and press o to select following distance
indication 3 114.
The minimum indicated distance is 0.5 seconds.
If there is no vehicle ahead or the
vehicle ahead is out of range, two
dashes will be displayed: -.- sec.
If Adaptive cruise control is active,
this page shows the alert sensitivity
setting instead of following distance
setting. 3 184.
Active emergency braking
Active emergency braking can help to reduce the damage and injury 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 3 192.
The feature uses various inputs (e.g.
camera sensor, radar sensor, brake
pressure, vehicle speed) to calculate
the probability of a frontal collision.9 Warning
This system is not intended to
replace the driver responsibility for driving the vehicle and looking
ahead. Its function is limited to
196Driving and operatingsupplemental use only to reduce
the vehicle speed before a
collision.
The system may not react for
pedestrians or animals. After a
sudden lane change, the system
needs a certain time to detect the
next preceding vehicle.
The driver shall always be ready to take action and apply the brakes
and steer to avoid collisions.
Functionality
If equipped only with front camera the active emergency braking operates in
forward gear above walking speed up to 53 mph.
With radar sensor active emergency
braking operates in forward gear
above walking speed at all speeds.
A precondition is that forward collision
alert with front camera system is not
deactivated by pressing V on the
steering wheel 3 192or, with radar
sensor, that it is not deactivated in the vehicle personalisation menu 3 124.
The system includes:
● brake preparation system
● emergency automatic braking
● forward looking brake assist
● intelligent brake assist (only with radar sensor)
Brake preparation system
When approaching a vehicle ahead
so quickly that a collision is likely, the brake preparation system slightly
pressurizes 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.
If equipped only with front camera the
system operates up to a speed of 50
mph.
Emergency automatic braking After activation of brake preparation
system and just before the imminent
collision, this function automatically
applies limited braking to reduce the
impact speed of the collision or
prohibit a crash. Depending on the situation, the vehicle mayautomatically brake moderately or
hard. This front automatic braking can
only occur if a vehicle ahead is
detected, indicated by the vehicle
ahead indicator A 3 192.
If equipped only with front camera the
system operates up to a speed of 37
mph.
Below a speed of 25 mph the system
can apply full braking.
Emergency automatic braking may
slow the vehicle to a complete stop to
try to avoid a potential crash. If this
happens, emergency automatic
braking may engage the electric
parking brake to hold the vehicle at a
stop. To release press the electric
parking brake button or firmly press
the accelerator pedal.9 Warning
Emergency automatic braking is
an emergency crash preparation
feature and is not designed to
avoid crashes. Do not rely on the
system to brake the vehicle.
Emergency automatic braking will
Driving and operating197not brake outside of its operating
speed range and only responds to
detected vehicles.
Forward looking brake assist
In addition to the brake preparation
system and emergency automatic
braking, the forward looking brake
assist function makes the brake assist more sensitive. Therefore, pressing
the brake pedal less strongly results
in immediate hard braking. This
function helps the driver brake
quicker and harder before the
imminent collision.
If equipped only with front camera the system operates up to a speed of 53
mph.
9 Warning
Active emergency braking is not
designed to apply hard
autonomous braking or to
automatically avoid a collision. It is designed to reduce the vehicle
speed before a collision. It may not
react for 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 wearingtheir seat belts.
Intelligent Brake Assist
If the vehicle is equipped with radar
sensor Intelligent brake assist may
activate when the brake pedal is
applied quickly by providing a boost
to braking based on the speed of
approach and distance to a vehicle
ahead.
Minor brake pedal pulsations or pedal movement during this time is normal
and the brake pedal should continue to be applied as needed. Intelligent
brake assist will automatically
disengage only when the brake pedal is released.
9 Warning
Intelligent brake assist may
increase vehicle braking in
situations when it may not be
necessary. You could block the
flow of traffic. If this occurs, take
your foot off the brake pedal and
then apply the brakes as needed.
Deactivation
On vehicles with front camera active
emergency braking can be
deactivated by repeatedly pressing
the gap switch V to Off setting,
198Driving and operating3 192. If deactivated a message is
displayed in the Driver Information
Centre.
On vehicles with radar sensor the
system can be disabled in the
personalisation menu in the Info-
display, 3 124.
System limitations In some cases, the active emergencybraking system may provide an
automatic braking in situations that
seem to be unnecessary, for instance
in parking garages, due to traffic signs in a curve or due to vehicles in
another lane. This is normal
operation, the vehicle does not need
service. Firmly apply the accelerator
pedal to override the automatic
braking.Emergency automatic braking may
not:
● detect a vehicle ahead on winding or hilly roads.
● detect all vehicles, especially vehicles with a trailer, tractors,
muddy vehicles, etc.
● detect a vehicle when weather limits visibility, such as in fog,rain, or snow.
To avoid malfunction keep the areas
of the camera sensor in the
windscreen and the radar sensor in
the radiator grille always clean from
dirt, dust, ice and snow.
Complete attention is always required
while driving, and you should be
ready to take action and apply the
brakes and/or steer the vehicle to
avoid crashes.
Fault
In case the system requires a service,
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 3 122.
Parking assist
General information When the trailer hitch is attached,
change the configuration settings in
the vehicle personalisation menu in
the Info-Display. Vehicle
personalisation 3 124.
When attaching a trailer or bike
carrier to the trailer hitch, the parking
assist is deactivated.
Rear parking assist9 Warning
It is the driver who bears full
responsibility for the parking
manoeuvre.
Always check the surrounding
area while reversing and using the rear parking assist system.
220Driving and operatingFor the values specific to your
vehicle, refer to the EEC Certificate of Conformity provided with your vehicle
or other national registration
documents.
General information
The official fuel consumption and
specific CO 2 emission figures quoted
relate to the EU base model with
standard equipment.
Fuel consumption data and CO 2
emission data are determined
according to regulation R (EC)
No. 715/2007 (in the latest applicable version), taking into consideration the
vehicle weight in running order, as specified by the regulation.
The figures are provided only for the
purpose of comparison between
different vehicle variants and must
not be taken as a guarantee for the
actual fuel consumption of a
particular vehicle. Additional
equipment may result in slightly
higher results than the stated
consumption and CO 2 figures.Furthermore, fuel consumption is
dependent on personal driving style
as well as road and traffic conditions.Trailer hitch
General information
Only use towing equipment that has
been approved for your vehicle.
Entrust retrofitting of towing
equipment to a workshop. It may be
necessary to make changes that
affect the cooling system, heat
shields or other equipment.
The bulb outage detection function for
trailer brake light cannot detect a
partial bulb outage, e.g. in case of four times five watt bulbs, the function only
detects lamp outage when only a
single five Watt lamp remains or none remain.
Fitting of towing equipment could
cover the opening of the towing eye. If this is the case use the coupling ball
bar for towing. Always keep the
coupling ball bar in the vehicle when
not in use.
Driving and operating221Driving characteristics and
towing tips
Before attaching a trailer, lubricate
the coupling ball. However, do not do
so if a stabiliser, which acts on the
coupling ball, is being used to reduce snaking movements.
During trailer towing do not exceed a
speed of 50 mph. A maximum speed
of 60 mph is only appropriate if an
oscillation damper is used and the
permissible gross trailer weight does
not exceed the vehicle's curb weight.
For trailers with low driving stability
and caravan trailers, the use of an
oscillation damper is strongly
recommended.
If the trailer starts snaking, drive more slowly, do not attempt to correct the
steering and brake sharply if
necessary.
When driving downhill, drive in the
same gear as if driving uphill and
drive at a similar speed.
Adjust tyre pressure to the value
specified for full load 3 292.Trailer towing
Trailer loadsThe permissible trailer loads are
vehicle and engine-dependent
maximum values which must not be
exceeded. The actual trailer load is the difference between the actual
gross weight of the trailer and the
actual coupling socket load with the
trailer coupled.
The permissible trailer loads are
specified in the vehicle documents. In general, they are valid for gradients
up to 12%.
The permissible trailer load applies
up to the specified incline and at sea
level. Since engine power decreases
as altitude increases due to the air
becoming thinner, therefore reducing
climbing ability, the permissible gross
train weight also decreases by 10%
for every 1000 metres of altitude. The gross train weight does not have to be
reduced when driving on roads with
slight inclines (less than 8%, e.g.
motorways).The permissible gross train weight must not be exceeded. This weight is specified on the identification plate
3 279.
Vertical coupling load
The vertical coupling load is the load
exerted by the trailer on the coupling
ball. It can be varied by changing the
weight distribution when loading the
trailer.
The maximum permissible vertical
coupling load (75 kg) is specified on
the towing equipment identification
plate and in the vehicle documents.
Always aim for the maximum load,
especially in the case of heavy
trailers. The vertical coupling load
should never fall below 25 kg.
Rear axle load
When the trailer is coupled and the
towing vehicle fully loaded, the
permissible rear axle load (see
identification plate or vehicle
documents) may be exceeded by
40 kg. If the permissible rear axle load is exceeded, a maximum speed of60 mph applies.
Driving and operating225Stow the coupling ball bar in the bag
and secure by fixing the strap through
the rear right lashing eye. Wrap
around twice and tighten the strap to
secure the bag.
Trailer stability assist
If the system detects snaking
movements, engine power is reduced and the vehicle/trailer combination isselectively braked until the snaking
ceases. While system is working keep
steering wheel as still as possible.
Trailer stability assist is a function of
the Electronic Stability Control 3 179.