Driving and operating199A precondition is that forward collision
alert in the vehicle personalisation
menu is not deactivated 3 126.
Activation
Forward collision alert with front
camera detects vehicles to distances
of approximately 60 metres and
operates automatically at all speeds
above walking speed.
Forward collision alert with radar
sensor detects vehicles to distances
of approximately 150 metres and
operates automatically at all speeds
above walking speed.
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. On
vehicles with head-up display, A is
projected on the windscreen.
The control indicator A changes to
yellow when the distance to a
preceding moving vehicle gets too
small.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.
When the time to a potential collision
with a vehicle in front gets too small
and a collision is imminent, the
collision alert symbol pops-up in the
Driver Information Centre and the
driver gets notified by a flashing red
LED stripe or the pop-up symbol in
the head-up display which is
projected on the windscreen in the
driver's field of view.
Simultaneously a warning chime
sounds. Depress the brake pedal and
steer the vehicle, if it is required by the
situation.
Selecting the alert sensitivity Press V or E to set the alert
sensitivity to near, medium or far.
202Driving and operating● Weather limits visibility, such asfog, rain, or snow.
● The sensor is blocked by snow, ice, slush, mud, dirt, windscreen
damage or affected by foreign
items, e.g. stickers.
Active emergency braking
Active emergency braking can help to reduce the damage and injury from
crashes with vehicles, pedestrians 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 3 198 or the Front pedestrian
protection alert 3 205.
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
supplemental use only to reduce
the vehicle speed before a
collision.
The system may not react to
animals. After a sudden lane
change, the system needs a
certain time to detect the next
preceding vehicle.
The driver must 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 85 km/h.
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 in the vehicle
personalisation menu 3 126.
The system includes: ● brake preparation system
● emergency automatic braking ● forward looking brake assist
● intelligent brake assist (only with radar sensor)
● front pedestrian protection system
Brake preparation system
When approaching a vehicle ahead
or a pedestrian 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 80
km/h.
Driving and operating203Emergency automatic brakingAfter 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 may
automatically brake moderately or
hard. This front automatic braking can
only occur if a vehicle ahead is
detected, indicated by the vehicle
ahead indicator A 3 198 . On vehicles
with front pedestrian protection, front automatic braking can also occur
when a pedestrian ahead is detected,
indicated by the pedestrian ahead
indicator 7.
If equipped only with front camera the system operates up to a speed of 80
km/h.
Below a speed of 40 km/h 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 electricparking 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
not brake outside of its operating speed range and only responds to
detected vehicles and
pedestrians.
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 85
km/h.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 to 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 must 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.
Intelligent Brake Assist
If the vehicle is equipped with radar
sensor Intelligent brake assist may
activate when the brake pedal is
204Driving and operatingapplied 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.
Front pedestrian protection
3 205.
Deactivation
Active emergency braking can be
deactivated in the personalisation
menu 3 126. If deactivated a
message is displayed in the Driver
Information Centre.
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 if the situation and the
surroundings permit.
In the following cases, Active
emergency braking performance is limited:
● Driving on winding or hilly roads.
● Detecting all vehicles, especially vehicles with a trailer, tractors,
muddy vehicles, etc.● Detecting a vehicle when weather limits visibility, such as in
fog, rain, or snow.
● During nighttime driving.
● Weather limits visibility, such as fog, rain, or snow.
● The sensor in the windscreen is blocked by snow, ice, slush, mud,dirt, windscreen damage or
affected by foreign items, e.g.
stickers.
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.
266Vehicle careA detected low tyre pressure
condition is indicated by the control
indicator w 3 110.
If w illuminates, stop as soon as
possible and inflate the tyres as
recommended 3 301.
Ensure that vehicle loading status
matches selected tyre pressure.
Vehicle loading status, see below in
this chapter.
After inflating, some driving may be
required to update the tyre pressure
values in the Driver Information
Centre. During this time w may
continue to illuminate.
If w illuminates at lower temperatures
and extinguishes after some driving,
this could be an indicator for
approaching a low tyre pressure
condition. Check tyre pressure.
Vehicle messages 3 124.
Only mount wheels with pressure
sensors, otherwise the tyre pressure
will not be displayed and w
illuminates continuously.
A spare wheel or temporary spare
wheel is not equipped with pressure
sensors. The tyre pressuremonitoring system is not operational
for these wheels. Control indicator w
illuminates. For the further three
wheels the system remains
operational.
The use of commercially available
liquid tyre repair kits can impair the
function of the system. Factory-
approved repair kits can be used.
Operating electronic devices or being
close to facilities using similar wave
frequencies could disrupt the tyre
pressure monitoring system.
Each time the tyres are replaced tyre
pressure monitoring system sensors
must be dismounted and serviced.
For the screwed sensor replace valve core and sealing ring, for clipped
sensor replace complete valve stem.
Use only original plastic valve caps to
protect valve on any damage.Caution
Do not use metal valve caps as
they lead to valve oxidation and
damage.
Vehicle loading status
Adjust tyre pressure to load condition
according tyre information label or
tyre pressure chart 3 301, and select
the appropriate setting in the Tyre
loading page under the Settings
menu in the Driver Information Centre 3 113. This setting determines the
reference pressures for the tyre
pressure warnings.
Depending on the display, the menu
Tyre loading only appears if the
vehicle is at a standstill and the
parking brake is applied. On vehicles
with automatic transmission the
selector lever must be in P.