192Driving and operatingA precondition is that forward collision
alert with front camera system is not
deactivated by pressing V on the
steering wheel or, with radar sensor,
that it is not deactivated in the vehicle
personalisation menu 3 123.
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.
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.
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 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 and
on some versions off.
Driving and operating193
The first button press shows the
current setting on the Driver
Information Centre. Additional button
presses will change this setting. The
chosen setting will remain until it is
changed. The alert timing will vary based on vehicle speed. The faster
the vehicle speed, the farther away
the alert will occur. Consider traffic
and weather conditions when
selecting the alert timing.Note that the alert timing sensitivity
setting is shared with the following
distance setting of the adaptive cruise
control. So changing the alert timing
sensitivity changes the adaptive
cruise control following distance
setting.
Deactivation
The system can be deactivated.
On forward collision alert with radar
sensor the system can be disabled by the personalisation menu, 3 123.
On forward collision alert with front
camera press V repeatedly until
Forward Collision Alert Off appears in
the Driver Information Centre.
If the forward collision alert was
deactivated, alert sensitivity is set to
"medium" when ignition is switched on next time.
The last selected setting will be stored
when the ignition is switched off.
General information9 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.
194Driving and operatingThe 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:
● on winding roads
● when weather limits visibility, such as fog, rain, or snow
● when the sensor 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.
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 turn
signal lever and turn the adjuster
wheel to choose following distance
indication page, 3 114On Uplevel display, select Info menu
via steering wheel buttons and press o to select following distance
indication 3 114.
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.
If Adaptive cruise control is active,
this page shows the alert sensitivity
setting instead of following distance
setting. 3 184.
Driving and operating195Active emergency braking
Active emergency braking can help to reduce 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 3 191.
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
pedestrians or 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 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 by pressing V on the
steering wheel 3 191or, with radar
sensor, that it is not deactivated in the
vehicle personalisation menu 3 123.
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 slightlypressurizes 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.
Emergency automatic braking After 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
196Driving and operatingonly occur if a vehicle ahead is
detected, indicated by the vehicle ahead indicator A 3 191.
If equipped only with front camera the
system operates up to a speed of 60
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.
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.
Driving and operating1979Warning
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,
3 191. 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, 3 123.
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.Emergency automatic braking may
not:
● detect a vehicle ahead on winding or hilly roads.
● detect all vehicles, especially vehicles with a trailer, tractors,
muddy vehicles, etc.
● detect a vehicle when weather limits visibility, such as in fog,rain, or snow.
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.
254Vehicle careThe 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 3 114.
Select ● Light for comfort pressure up to
three people.
● Eco for Eco pressure up to three
people.
● Max for full loading.
Uplevel display:
Select the Tyre load page under the
Options Menu in the Driver
Information Centre 3 114.
Select ● Light for comfort pressure up to
three people.
● Eco for Eco pressure up to
three people.
● Max for full loading.
Tyre pressure sensor matching
process
Each tyre pressure sensor has a
unique identification code. The
identification code must be matched
to a new wheel position after rotating the wheels or exchanging the
complete wheel set and if one or more tyre pressure sensors were replaced.
The tyre pressure sensor matching
process should also be performed
after replacing a spare wheel with a
road wheel containing the tyre
pressure sensor.
The malfunction light w and the
warning message or code should go
off at the next ignition cycle. The
sensors are matched to the wheel
positions, using a relearn tool, in the following order: left side front wheel,
right side front wheel, right side rear
wheel and left side rear wheel. The
turn signal light at the current active
position is illuminated until sensor is
matched.
Consult a workshop for service. There are two minutes to match the first
wheel position, and five minutes
overall to match all four wheel
Vehicle care255positions. If it takes longer, the
matching process stops and must be restarted.
The tyre pressure sensor matching
process is:
1. Apply the parking brake.
2. Turn the ignition on.
3. On vehicles with automatic transmission: set the selector
lever to P.
On vehicles with manual
transmission: select neutral.
4. Midlevel display: Use MENU on the turn signal
lever to select the Vehicle
Information Menu ? in the
Driver Information Centre.
Uplevel display:
Press p on the steering wheel to
open main menu page.
Select the Info page with Q or P.
Confirm with 9.
5. Select the tyre pressure menu. Midlevel display:
Uplevel display:
6. Midlevel display: Press SET/CLR to begin the
sensor matching process. A
message requesting acceptance
of the process should be
displayed.
Press SET/CLR again to confirm
the selection. The horn sounds
twice to indicate that the receiver
is in relearn mode.
Uplevel display:
Press 9 to begin the sensor
matching process. The horn
sounds twice to indicate that the receiver is in relearn mode.
7. Start with the left side front wheel.
8. Place the relearn tool against the tyre sidewall, near the valve stem.Then press the button to activate
the tyre pressure sensor. A horn
chirp confirms that the sensor
identification code has been
matched to this wheel position.
9. Proceed to the right side front wheel, and repeat the procedure
in Step 8.
10. Proceed to the right side rear wheel, and repeat the procedure
in Step 8.
11. Proceed to the left side rear wheel, and repeat the procedure
in Step 8. The horn sounds twice