Driving and operating187Fault
If the adaptive cruise control does not work due to temporary conditions
(e.g. blockage by ice, overheated
brakes or low speed manoeuvres) or
if there is a permanent system error,
then a message is displayed in the
Driver Information Centre.
Vehicle messages 3 122.
Forward collision alert The forward collision alert may help toavoid or reduce the harm caused by
front-end crashes.
If the vehicle is equipped with
conventional cruise control, the
forward collision alert uses the front
camera in the windscreen to detect a
vehicle directly ahead, in your path.
If the vehicle is equipped with
adaptive cruise control, the forward
collision alert uses the radar sensor to detect a vehicle directly ahead, in
your path.
Number plate mounting 3 222
A vehicle ahead is indicated by the
control indicator A.
If a vehicle directly ahead is
approached too quickly, a warning
chime and alert in the Driver
Information Centre is provided.
A precondition is that forward collision
alert with front camera system or
radar sensor is not deactivated in the
vehicle personalisation menu 3 124.
Activation
Forward collision alert with front
camera detects vehicles to distances
and operates automatically at all
speeds above walking speed.
Forward collision alert with radar
sensor detects vehicles to distances
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.
The control indicator A changes to
yellow when the distance to a
preceding moving vehicle gets too
small 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.
Driving and operating189The 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 react
also to other objects.
In the following cases, forward
collision alert may not detect a vehicle ahead or sensor performance is
limited:
● driving on winding or hilly roads● 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
Following distance
indication
The following distance indication
displays the distance to a preceding
moving vehicle. The front camera in
the windscreen is used to detect the
distance of a vehicle directly ahead in the vehicle's path. It is active at
speeds above 40 km/h. Number plate
mounting 3 222
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 indicator
lever and turn the adjuster wheel to
choose following distance indication
page 3 115
On Uplevel display, select Info menu
via steering wheel buttons and press
o to select following distance
indication 3 115.
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.
190Driving and operating
If Adaptive cruise control is active,
this page shows the alert sensitivity
setting instead of following distance setting 3 179.
Active emergency braking Active emergency braking can help toreduce 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 3 187.
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 for
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 80 km/h.
With radar sensor active emergency
braking operates in forward gear
above walking speed at all speeds.
Number plate mounting 3 222.
A precondition is that forward collision
alert 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
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.
If equipped only with front camera the
system operates up to a speed of
80 km/h.
Driving and operating191Emergency 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 3 187.
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 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
not 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
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 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.
192Driving and operatingMinor brake pedal pulsations or pedalmovement 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,
3 187. 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.
We recommend to deactivate the
system or set it to alert only in the
following cases:
● when the vehicle is being towed
● if a trailer is attached to the vehicle
● before using an automatic car wash with ignition switched on
● if the windscreen has been damaged close to the camera
● if the front bumper has been damaged
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.
Driving and operating193In 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 infog, 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
stickered.
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.
Front pedestrian protection Front pedestrian protection may helpto avoid or reduce the harm causedby front-end crashes with nearby
pedestrians when driving in a forward
gear.
The system uses the front camera in
the windscreen to detect a pedestrian directly ahead, in your path.
Front pedestrian protection can
detect and alert to pedestrians in a
forward gear at speeds between
8 km/h and 80 km/h. Additionally
Front pedestrian protection can
provide a boost to braking or
automatically brake the vehicle.During daytime driving, the system
detects pedestrians up to a distance
of approx. 40 m. During nighttime
driving, system performance is
limited.
Front pedestrian protection can be
set to Off, Alert , or Alert & Brake in
vehicle personalisation 3 124.9 Danger
Front pedestrian braking does not
provide an alert or automatically
brake the vehicle, unless it detects
a pedestrian.
The system may not detect
pedestrians, including children,
when the pedestrian is not directly ahead, not fully visible, not
standing upright, or when part of a
group.
Front pedestrian protection includes:
● detecting front pedestrian ahead● front pedestrian alert
● automatic braking
252Vehicle careAfter inflating, some driving may be
required to update the tyre pressure
values in the Driver Information
Centre. During this time w may
illuminate.
If w illuminates at lower temperatures
and extinguishes after driving, this
could be an indicator for approaching
a low tyre pressure condition. Check
tyre pressure.
Vehicle messages 3 122.
If the tyre pressure must be reduced
or increased, switch off ignition.
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 pressure
monitoring system is not operational
for these tyres. Control indicator w
illuminates. For the further three
tyres, 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 the
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 to the tyre information label or tyre pressure chart 3 285, and
select the appropriate setting in Tyre
Load within the Vehicle Information
Menu 3 115. This setting determines
the reference pressures for the tyre
pressure warnings.
The Tyre Load menu only appears
when the vehicle is at a standstill and the parking brake is applied. On
vehicles with automatic transmission
the selector lever must be in P.
Midlevel display:
Select the Tyre load page under the
Vehicle Information Menu ? in the
Driver Information Centre 3 115.
Customer information295Operating data in the vehicleControl units process data for
operation of the vehicle.
This data includes, e.g.: ● vehicle status information (e.g. wheel rotation rate, speed,
movement delay, lateral
acceleration, "seatbelts
fastened" display),
● ambient conditions (e.g. temperature, rain sensor,
distance sensor).
As a rule such data is transient, not
stored for longer than an operational
cycle, and only processed on board
the vehicle itself. Control units often
include data storage (including the
vehicle key). This is used to allow information to be documented
temporarily or permanently on vehicle
condition, component stress,
maintenance requirements and
technical events and errors.Depending on the technical
equipment level, the data stored is as follows:
● system component operating states (e.g. fill level, tyre
pressure, battery status)
● faults and defects in important system components (e.g. lights,
brakes)
● system reactions in special driving situations (e.g. triggering
of an airbag, actuation of the
stability control systems)
● information on events damaging the vehicle
● for electric vehicles the amount of
charge in the high-voltage
battery, estimated range
In special cases (e.g. if the vehicle
has detected a malfunction), it may be
necessary to save data that would
otherwise just be volatile.
When you use services (e.g. repairs,
maintenance), the operating data
saved can be read together with the
vehicle identification number and
used when necessary. Staff working
for the service net-work ( e.g. garages,manufacturers) or third parties (e.g.
breakdown services) can read the
data from the vehicle. The same
applies to warranty work and quality
assurance measures.
Data is generally read via the OBD
(On-Board Diagnostics) port
prescribed by law in the vehicle. The operating data which is read out,
documents the technical condition of
the vehicle or individual components
and assists with fault diagnosis,
compliance with warranty obligations
and quality improvement. This data,
in particular information on
component stress, technical events,
operator errors and other faults, is
transmitted to the manufacturer
where appropriate, together with the
vehicle identification number. The
manufacturer is also subject to
product liability. The manufacturer
potentially also uses operating data
from vehicles for product recalls. This
data can also be used to check
customer warranty and guarantee
claims.