Driving and operating173Brakes
The brake system comprises two
independent brake circuits.
If a brake circuit fails, the vehicle can
still be braked using the other brake
circuit. However, braking effect is
achieved only when the brake pedal
is depressed firmly. Considerably
more force is needed for this. The
braking distance is extended. Seek the assistance of a workshop before
continuing the journey.
When the engine is not running, the
support of the brake servo unit
disappears once the brake pedal has
been depressed once or twice.
Braking effect is not reduced, but
braking requires significantly greater
force. It is especially important to bear this in mind when being towed.
Control indicator R 3 105.
Antilock brake system
Antilock brake system (ABS)
prevents the wheels from locking.ABS starts to regulate brake pressure as soon as a wheel shows a tendency to lock. The vehicle remains
steerable, even during hard braking.
ABS control is made apparent
through a pulse in the brake pedal
and the noise of the regulation
process.
For optimum braking, keep the brake
pedal fully depressed throughout the
braking process, despite the fact that
the pedal is pulsating. Do not reduce
the pressure on the pedal.
After starting off, the system performs
a self-test which may be audible.
Control indicator u 3 106.
Adaptive brake light During full braking, all three brake
lights flash for the duration of ABS
control.
Fault9 Warning
If there is a fault in the ABS, the
wheels may be liable to lock due
to braking that is heavier than
normal. The advantages of ABS are no longer available. During
hard braking, the vehicle can no longer be steered and may
swerve.
Have the cause of the fault remedied
by a workshop.
174Driving and operatingParking brake
Manual parking brake9 Warning
Always apply parking brake firmly
without operating the release
button, and apply as firmly as
possible on a downhill or uphill
slope.
To release the parking brake, pull
the lever up slightly, press the
release button and fully lower the
lever.
To reduce the operating forces of
the parking brake, depress the
brake pedal at the same time.
Control indicator R 3 105.
Electric parking brake
Applying when vehicle is stationary
9 Warning
Pull switch m for a minimum of
one second until control indicator
m illuminates constantly and
electric parking brake is applied
3 105. The electric parking brake
operates automatically with
adequate force.
Before leaving the vehicle, check
the electric parking brake status.
Control indicator m 3 105.
The electric parking brake can always
be activated, even if the ignition is off.
Do not operate electric parking brake
system too often without engine
running as this will discharge the vehicle battery.
Releasing
Switch on ignition. Keep brake pedal
depressed and then push switch m.
Drive away function Vehicles with manual transmission:
Depressing the clutch pedal and then
slightly releasing the clutch pedal and slightly depressing the accelerator
pedal releases the electric parking
brake automatically. This is not
possible when switch m is pulled at
the same time.
184Driving and operatingIt then adjusts the vehicle speed to
follow the vehicle ahead at the
selected following distance. The
vehicle speed increases or decreases to follow the vehicle in front, but will
not exceed the set speed. It may
apply limited braking with activated
brake lights.
The adaptive cruise control can store
and maintain speeds over approx.
15 mph. If following a vehicle ahead
driving slower than 15 mph, the
slower speed will be set. On vehicles
with automatic transmission, the
system can also brake to a stop.
Adaptive cruise control uses a radar
sensor to detect vehicles ahead. If no
vehicle is detected in the driving path, the adaptive cruise control will
behave like a traditional cruise
control.
For safety reasons, the system
cannot be activated before the brake
pedal or clutch pedal has been
depressed once after switching on
ignition.
Adaptive cruise control is mainly
advised to be used on long straight
roads like highways or country roads
with steady traffic. Do not use the
system if it is not advisable to
maintain a constant speed.
Control indicator A 3 109, m 3 109,
C 3 109.9 Warning
The complete driver attention is
always required while driving with adaptive cruise control. The driver stays fully in control of the vehicle
because the brake pedal, the
accelerator pedal and the cancel
switch have priority over any
adaptive cruise control operation.
Switching on
Press C to switch on adaptive cruise
control. The control indicator m in the
instrument cluster illuminates white.
Additionally C appears in the Driver
Information Centre.
Activation by setting the speed
Adaptive cruise control can be
activated between 15 mph and
112 mph.
Accelerate to the desired speed and
turn thumb wheel to SET/-, the
current speed is stored and
maintained. Control indicator m in the
instrument cluster illuminates green.
Driving and operating189● Adaptive cruise control does notbrake for pedestrians, animals,
very slow speed driving or
stopped vehicles.
● Do not use adaptive cruise control when towing a trailer.
Bends
The adaptive cruise control calculates
a predicted path based on the
centrifugal force. This predicted path
considers the current bend
characteristic, but cannot consider a
future bend change. The system may lose the current vehicle ahead or
consider a vehicle which is not in the
actual lane. This can happen when
entering or exiting a bend or if the
bend gets stronger or weaker. If it no
longer detects any vehicle ahead,
then control indicator A will
extinguish.
If the centrifugal force is too high in a bend, the system slows down the vehicle slightly. This braking level is
not designed to avoid spinning-off the
bend. The driver is responsible for
reducing the selected speed before
entering a bend and in general to
adapt the speed to the road type and
to existing speed limits.
Motorways
On motorways, adapt the set speed
to the situation and the weather.
Always consider that adaptive cruise
control has a limited visibility range, a
limited braking level and a certain
reaction time to verify if a vehicle is on
the driving path or not. Adaptive
cruise control may not be able to
brake the vehicle in time to avoid a
collision with a much slower vehicle or after a lane change. This is
particularly true if driving fast or if the
visibility is reduced due to weather
conditions.
While entering or exiting a motorway,
adaptive cruise control may lose the
vehicle ahead and accelerate up to
the set speed. For this reason,
decrease the set speed before the
exit or entry of a motorway.
Vehicle path changes
If another vehicle enters your driving
path, adaptive cruise control will first
consider the vehicle when it is
completely in your path. Be ready to
take action and depress the brake
pedal, if you need to brake more
quickly.
192Driving and operating
Press E, the current setting is shown
in the Driver Information Centre.
Press E again to change the alert
sensitivity. The setting is also displayed in the Driver Information
Centre.Note that the alert timing sensitivity
setting is shared with the following
distance setting of the adaptive cruise control 3 183. So changing the alert
timing sensitivity changes the
adaptive cruise control following
distance setting.
Alerting the driver
The vehicle ahead control indicator A illuminates green in the instrument
cluster when the system has detected
a vehicle in the driving path.
The control indicator A changes to
yellow when the distance to a
preceding moving vehicle gets too
short or when approaching another
vehicle too rapidly.Caution
The colour lighting of this control
indicator does not correspond to
local traffic laws on following
distance. The driver bears full
responsibility for maintaining safe
following distance according to
applicable traffic rules, weather
and road conditions etc. at all
times.
If a collision is imminent, the collision
alert symbol pops-up in the Driver
Information Centre and a warning
chime sounds. Depress the brake
pedal if it is required by the situation.
Driving and operating195Active 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 3 191.
The feature uses various inputs (e.g.
radar sensor, brake pressure, vehicle speed) to calculate the probability of
a frontal collision.
Active emergency braking operates automatically above walking speed, provided that Auto Collision
Preparation setting is not deactivated
in the vehicle personalisation menu
3 120.
The system includes: ● brake preparation system
● emergency automatic braking
● forward looking brake assist9Warning
This system is not intended to
replace the driver responsibility for driving the vehicle and looking
ahead. Its function is limited to
supplemental use only. The driver must 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.
Below a speed of 11 mph the system
can apply full braking.
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,
depressing the brake pedal less
strongly results in immediate hard
braking. This function helps the driver
brake quicker and harder before the
imminent collision.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 stopped vehicles,
pedestrians or animals. After a
Driving and operating205Detection zones
The system sensors cover a zone of
approx. 3.5 metres parallel on both
vehicle sides and approx. 3 metres
rearwards on side blind zone alert
(A) and approx. 70 metres rearwards
on lane change alert (B) on parallel
lanes. The zones start at each
exterior mirror. The height of the zone
is approx. between 0.5 metres and
2 metres off the ground.
Deactivation
Activation or deactivation of the lane
change alert can be set in the vehicle personalisation menu in the Colour-
Info-Display.
Select the relevant setting in Settings,
I Vehicle in the Colour-Info-Display.
Colour-Info-Display 3 117.
Vehicle personalisation 3 120.
The system is deactivated if the
vehicle is towing a trailer.
Deactivation is indicated by a
message in the Driver Information
Centre.
Notice
After production, the system
requires a calibration. For optimal performance, drive as soon as
possible on a straight highway road
with roadside objects, e.g. guardrails
and barriers for some distance.
Fault
Occasional missed alerts can occur
under normal circumstances or in
sharp curves. The system can
temporarily alert of objects in the blind spot at specific weather conditions
(rain, hail etc). Driving on a wet road
or in the transitions from a dry area to a wet area can cause the system to
light up, as water splash can be
interpreted as an object. Otherwisethe system may light up due to
guardrails, signs, trees, shrubs or
other immobile objects. This is normal operation and the system does not
need to be serviced.
Lane change alert may not operate
when the left or right corners of the
rear bumper are covered with mud,
dirt, snow, ice or slush. Cleaning
instructions 3 271.
In the event of a fault in the system or if the system does not work due to
temporary conditions, a message is
displayed in the Driver Information Centre. Seek the assistance of a
workshop.
Rear view camera
The rear view camera assists the
driver when reversing, by displaying a view of the area behind the vehicle.
The view of the camera is displayed
in the Colour-Info-Display.
206Driving and operating9Warning
The rear view camera does not
replace driver vision. Note that
objects that are outside the
camera's field of view and the
advanced parking assist sensors,
e.g. below the bumper or
underneath the vehicle, are not
displayed.
Do not reverse the vehicle by only looking at the Info-Display and
check the surrounding area
behind and around the vehicle
before reversing.
Activation
Rear view camera is automatically
activated when reverse gear is
engaged.
Functionality
The camera is mounted between the
number plate lights and has a viewing angle of 130°.
Due to the high position of the camera
the rear bumper can be seen on the
display as a guide to position.
The area displayed by the camera is
limited. The distance of the image that appears on the display differs from
the actual distance.
Guiding lines
Dynamic guiding lines are horizontal
lines in 1 metre intervals projected on
the picture to define the distance to
shown objects.
Trajectory lane of the vehicle is
shown in accordance with the
steering angle.