Driving and operating187Brake preparation system
When approaching a vehicle ahead
so quickly that a collision is likely, the brake preparation system slightlypressurises 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 the imminent 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
vehicle personalisation menu in the
Info-Display.
Select the relevant setting in
Settings in the Info-Display.
Vehicle personalisation 3 125.
Fault
In the event of a system service
requirement, a message is displayed
in the Driver Information Centre.
Driving and operating191mirror, when detecting objects that
may not be visible in the interior and
exterior mirrors.
The system's sensors are located in
the bumper on the left and right side
of the vehicle.9 Warning
Side blind spot alert does not
replace driver vision.
The system does not detect:
● vehicles outside the side blind zones which may be rapidly
approaching
● pedestrians, cyclists or animals
Before changing a lane, always
check all mirrors, look over the
shoulder and use the turn signal.
When the system detects a vehicle in the side blind zone while driving
forward, either while passing a
vehicle or being passed, a yellow
warning symbol B will illuminate in
the relevant exterior mirror. If the
driver then activates the turn signal,
the warning symbol B starts flashing
yellow as a warning not to change
lanes.
Note
If the passing vehicle is at least
10 km/h faster than the passed
vehicle, the warning symbol B in the
relevant exterior mirror may not
illuminate.
Side blind spot alert is active from
speeds of 10 km/h up to 140 km/h.
Driving faster than 140 km/h
deactivates the system, indicated by
low lighting warning symbols B in
both exterior mirrors. Reducing the speed again will extinguish the
warning symbols. If a vehicle is then
detected in the blind zone, the
warning symbols B will illuminate as
normal on the relevant side.
When the vehicle is started, both exterior mirror displays will briefly
illuminate to indicate that the system
is operating.
The system can be activated or
deactivated in the Info-Display,
vehicle personalisation 3 125.
The system is deactivated if the
vehicle is towing a trailer.
Deactivation is indicated by a
message in the Driver Information
Centre.
Detection zones
The detection zones start at the rear
bumper and extend approx.
three metres rearwards and to the
sides. The height of the zone is
approx. between half a metre and two metres off the ground.
194Driving and operatingFault
Fault messages are displayed with a 9 on the top line of the Info-Display.
The rear view camera may not
operate properly when:
● The surrounding area is dark.● The sun or the beam of headlights is shining directly into
the camera lens.
● Ice, snow, mud, or anything else covers the camera lens. Clean
the lens, rinse it with water, and
wipe it with a soft cloth.
● The tailgate is not closed correctly.
● The vehicle had a rear-end accident.
● There are extreme temperature changes.Traffic sign assistant
Functionality
The traffic sign assistant system
detects designated traffic signs via a
front camera and displays them in the
Driver Information Centre.
Traffic signs which will be detected
are:
Limit and no passing signs ● speed limit
● no passing
● end of speed limit
● end of no passingRoad signs
beginning and end of:
● city regions (country specific)
● motorways
● A-roads
● play streetsAdd-on signs ● additional hints to traffic signs
● restriction of trailer towing
● tractor constraints
● wet warning
● ice warning
● direction arrows
Speed limit signs are displayed in the
Driver Information Centre until the
next speed limit sign or end of speed
limit is detected or up to a defined sign timeout.
Driving and operating195Combinations of multiple signs in the
display are possible.
An exclamation mark in a frame
indicates that there is an additional
sign detected which is not recognised
by the system.
The system operates without loss of
performance up to a speed of
200 km/h depending on the lighting
conditions. At night the system is
active up to a speed of 160 km/h.
Display indication Information about the currently valid
traffic signs is available on the
designated traffic sign assistant page in the Driver Information Centre.
Additionally, the currently valid speed
limit is displayed permanently in the
lower line of the Driver Information
Centre. In case a speed limit with
addon is available, a + symbol is
displayed in this area.
Choose ? via MENU and select
traffic sign assistant page with the adjuster wheel on the turn signal lever
3 117.
When another page on the Driver
Information Centre menu was
selected and then traffic sign
assistant page is chosen again, the
last recognised traffic sign will be
displayed.
Alert function
The alert function can be activated or
deactivated in the setting menu of the
traffic sign assistant page.
Once activated and when the traffic
sign detection page is currently not
displayed, newly detected speed limit
and no passing signs are displayed
as popup alerts in the Driver
Information Centre.
Driving and operating197Reasons for signs being cleared:● A predefined distance was driven
or time has elapsed (differs for
each sign type)
● Vehicle drives through a turn
● The speed becomes slower than 52 km/h (city entry detection)
Fault
The traffic sign assistant system may
not operate correctly if:
● The area of the windscreen, where the front camera is
located, is not clean or affected
by foreign items, e.g. stickers.
● Traffic signs are completely or partially covered or difficult to
discern.
● There are adverse environmental
conditions, e.g. heavy rain, snow,direct sunlight or shadows.
● Traffic signs are incorrectly mounted or damaged.
● Traffic signs do not comply with the Vienna Convention on traffic
signs (Wiener Übereinkommen
über Straßenverkehrszeichen).Caution
The system is intended to help the driver within a defined speed
range to discern certain traffic
signs. 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
198Driving and operatingThe lane departure warning system isactivated 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 56 km/h 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.
At speeds below 56 km/h the system
is inoperable.
Fault
The lane departure warning system may not operate properly when:
● The windscreen is not clean.
● There are adverse environmental
conditions like heavy rain, snow,
direct sunlight or shadows.
The system can not operate when no
lane marking is detected.Fuel
Fuel for petrol engines Only use unleaded fuel that complies
with European standard EN 228 or
equivalent.
The engine is capable of running with
fuel that contains up to 10% ethanol
(e.g. named E10).
Use fuel with the recommended
octane rating. A lower octane rating
can reduce engine power and torque
and slightly increases fuel
consumption.Caution
Do not use fuel or fuel additives
that contain metallic compounds
such as manganese-based
additives. This may cause engine
damage.
Driving and operating199Caution
Use of fuel that does not comply toEN 228 or equivalent can lead to
deposits or engine damage.
Caution
Use of fuel with a lower octane
rating than the lowest possible
rating could lead to uncontrolled combustion and engine damage.
The engine specific requirements
regarding octane rating are given in
the engine data overview 3 268. A
country specific label at the fuel filler
flap can supersede the requirement.
Fuel additives outside Europe
Fuel should contain detergent
additives that help prevent engine
and fuel system deposits from
forming. Clean fuel injectors and
intake valves will allow the emission
control system to work properly.
Some fuel does not contain sufficient
quantities of additive to keep fuel
injectors and intake valves clean.
To make up for this lack of
detergency, add Fuel System
Treatment PLUS to the fuel tank at
every engine oil change or every
15,000 km, whichever occurs first. It
is available at your workshop.
Fuels containing oxygenates such as
ethers and ethanol, as well as
reformulated fuel, are available in
some cities. If these fuels comply with the previously described
specification, then they are
acceptable to use. However, E85
(85% ethanol) and other fuels
containing more than 15% ethanol
must be used only in FlexFuel
vehicles.Caution
Do not use fuel containing
methanol. It can corrode metal
parts in the fuel system and also
damage plastic and rubber parts.
This damage would not be
covered by the vehicle warranty.
Some fuels, mainly high octane
racing fuels, can contain an octane
enhancing additive called
methylcyclopentadienyl manganese
tricarbonyl (MMT). Do not use fuels or fuel additives with MMT as they can
reduce spark plug life and affect
emission control system
performance. The malfunction
indicator light Z may illuminate
3 112. If this occurs, seek the
assistance of a workshop.
Fuel for diesel engines Only use diesel fuel that complies
with EN 590 and which has a sulphur
concentration of max. 10 ppm.
Fuels with a biodiesel (compliant with
EN 14214) content of max. 7% by
volume may be used (e.g. named
B7).
If travelling in countries outside the
European Union, occasional use of
Euro-Diesel fuel with a sulphur
concentration below 50 ppm is
possible.
200Driving and operatingCaution
Frequent usage of diesel fuelcontaining more than 15 ppm
sulphur will cause severe engine
damage.
Caution
Use of fuel that does not comply to EN 590 or similar can lead to
engine powerloss, increased wear
or engine damage and may affect
your warranty.
Do not use marine diesel oils, heating
oils, Aquazole and similar diesel-
water emulsions. Diesel fuels must
not be diluted with fuels for petrol
engines.
Fuel for natural gas operation
Use natural gas with a methane
content of approx. 78 - 99%. L-gas
(low) has approx. 78 - 87% and H-gas (high) has approx. 87 - 99%. Biogas
with the same methane content can
also be used if it has been chemically
prepared and desulphurised.
Only use natural gas or biogas that complies with DIN 51624.
Liquid gas or LPG must not be used.
Fuel selector
Pressing Y switches between petrol
and natural gas operation. Switching
is not possible at high loads (e.g.
powerful acceleration, driving at full
throttle). The LED status shows the
current operating mode.
1 off:natural gas
operation1 illumi‐
nates:petrol operation1 flashes:no switching is
possible, one type of
fuel is empty
As soon as the natural gas tank is empty, petrol operation is
automatically engaged until the
ignition is switched off.
If the natural gas tank is not refuelled, the system must be manually
switched to petrol operation before
the engine is restarted. This will
prevent damage to the catalytic
converter (overheating caused by
irregular fuel supply).
If the selector switch is operated
several times within a short time, a
switchover inhibitor is activated. The
engine remains in the current
operating mode. The inhibitor
remains active until the ignition is
switched off.
A slight loss of power and torque can
be expected during petrol operation.
You must therefore adapt your driving