188Driving and operating
SettingsSettings 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.
Alerting 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.
Driving and operating189
Deactivation
The system can be deactivated.
Press 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 onother 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 lane.
It is active at speeds above 25 mph.
When a preceding vehicle is detected ahead, the distance is indicated inseconds, displayed on a page in the
Driver Information Centre 3 117.
Press MENU on the turn signal lever
to select Vehicle Information Menu
X and turn the adjuster wheel to
choose following distance indication
page.
190Driving and operating
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 3 186.
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 3 129.
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
Driving and operating191
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, 3 129.
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.
Driving and operating205signs. Do not ignore traffic signs
which are not displayed by the
system.
The system does not discern any
other than the conventional traffic signs that might give or end a
speed limit.
Do not let this special feature
tempt you into taking risks when
driving.
Always adapt speed to the road
conditions.
The driver assistance systems do not relieve the driver from full
responsibility for vehicle
operation.
Lane departure warning
The lane departure warning system
observes the lane markings between
which the vehicle is driving via a front camera. The system detects lane
changes and warns the driver in the
event of an unintended lane change
via visual and acoustic signals.
Criteria for the detection of an
unintended lane change are:
■ No operation of turn signals.
■ No brake pedal operation.
■ No active accelerator operation or speeding-up.
■ No active steering.
If the driver is active, no warning will
be issued.
Activation
The lane departure warning system is activated by pressing ). The
illuminated LED in the button
indicates that the system is switched
on. When the control indicator ) in
the instrument cluster illuminates
green, the system is ready to operate.
The system is only operable at
vehicle speeds above 35 mph and if
lane markings are available.
When the system recognises an
unintended lane change, the control
indicator ) changes to yellow and
flashes. Simultaneously a chime
sound is activated.
Deactivation
The system is deactivated by
pressing ), the LED in the button
extinguishes.
Driving and operating215
General informationThe 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 version
respectively applicable), 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.Natural gas
The fuel consumption information
was obtained using reference fuel
G20 (methane proportion
99 - 100 mol%) under prescribed
driving conditions. When using
natural gas with a lower proportion of
methane, the fuel consumption can
differ from the specified values.Trailer hitch
General information
Only use towing equipment that has
been approved for your vehicle.
Vehicles with natural gas engines
require special towing equipment.
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
4x 5 Watt bulbs, the function only
detects lamp outage when only a
single 5 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.
216Driving and operatingDriving characteristics and
towing tips Before attaching a trailer, lubricatethe coupling ball. However, do not do
so if a stabiliser, which acts on the
coupling ball, is being used to reduce
snaking movements.
For trailers with low driving stability
and caravan trailers with a permitted
gross vehicle weight of more than
1300 kg the use of a stabiliser is
strongly recommended when driving
above 50 mph.
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 3 285.Trailer towing
Trailer loads The 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 max. 12 %.
The permitted trailer load applies up
to the specified incline and up to an
altitude of 1000 metres above 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 additional
altitude. The gross train weight doesnot 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
3 270.
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) 2)
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.2) Engines B16DTH, B16DTJ, B20DTH and B20DTJ: Depending on the equipment the maximum permissible vertical coupling load can
be 75 kg or 60 kg.
Driving and operating219
Eye for break-away stopping cable
Attach breakaway stopping cable to
eye.
Check that the coupling ball bar is correctly installed
■ Green marking on rotary knob must
point towards green marking on
coupling ball bar.
■ There must be no gap between the
rotary handle and the coupling ball
bar.
■ The coupling ball bar must be firmly
engaged in the opening.
■ The coupling ball bar must be locked and the key removed.9 Warning
Towing a trailer is permitted only
when a coupling ball bar is fitted correctly. If the coupling ball bardoes not engage correctly, seekthe assistance of a workshop.
Dismounting the coupling ball
bar
Open the protective flap and turn the
key to position c to unlock the
coupling ball bar.
Pull out rotary handle and turn
clockwise as far as it will go. Pull out coupling ball bar downwards.
Insert sealing plug in opening. Fold away socket.
Trailer stability assist If the system detects snaking
movements, engine power is reduced
and the vehicle/trailer combination is
selectively braked until the snaking ceases. While system is working keep steering wheel as still as possible.
Trailer stability assist (TSA) is a
function of the Electronic Stability
Control 3 174.