
Warning and display messages in the
multifunction displayXActivate ATTENTION ASSIST using the on-
board computer ( Y page 207).
Symbol : appears in the multifunction
display.
If ATTENTION ASSIST is active, you will be
warned no sooner than 20 minutes after your
journey has begun. You will then hear an
intermittent warning tone twice, and the
Attention Assist: Time for a rest?
message appears in the multifunction
display.
XIf necessary, take a break.XPress a to confirm the message.
On long journeys, take regular breaks in good
time to allow yourself to rest properly. If you
do not take a break and ATTENTION ASSIST
still detects typical indicators of fatigue or
increasing lapses in concentration, you will be
warned again after 15 minutes at the earliest.
ATTENTION ASSIST is reset when you
continue your journey and starts assessing
your tiredness again if:
R you switch off the engine.
R you take off your seat belt and open the
driver's door, e.g. for a change of drivers or
to take a break.
Lane Tracking package
General notes
The Lane Tracking package consists of Blind
Spot Assist ( Y page 186) and Lane Keeping
Assist ( Y page 188).
Blind Spot Assist
Important safety notes
Blind Spot Assist uses a radar sensor system
to monitor the areas on both sides of your
vehicle. It supports you from speeds of
approximately 20 mph (30 km/h). A warning
display in the exterior mirrors draws your
attention to vehicles detected in the
monitored area. If you then switch on the
corresponding turn signal to change lane, you
will also receive an optical and audible
collision warning. Blind Spot Assist uses
sensors in the rear bumper for monitoring
purposes.
GWARNING
Blind Spot Assist is only an aid designed to
assist driving. It may fail to detect some
vehicles and is no substitute for attentive
driving.
Blind Spot Assist cannot detect road and
traffic conditions. It may fail to detect narrow
vehicles, such as motorcycles or bicycles, or
may only detect them too late.
Monitoring may be affected by dirty sensors,
strong spray or poor visibility caused by snow,
rain or mist, for example. In this case, vehicles
are detected late or not at all.
Always pay attention to traffic conditions and
your surroundings. Otherwise, you may fail to
recognize dangers in time, cause an accident
and injure yourself and others.
i USA only:
This device has been approved by the FCC
as a “Vehicular Radar System”. The radar
sensor is intended for use in an automotive
radar system only. Removal, tampering, or
altering of the device will void any
warranties, and is not permitted by the
FCC. Do not tamper with, alter, or use in
any non-approved way.
Any unauthorized modification to this
device could void the user’s authority to
operate the equipment.
186Driving systemsDriving and parking

monitoring range. This warning is always
given when a vehicle enters the blind spot
monitoring range from behind or from the
side. When you are passing another vehicle,
the warning is emitted only if the difference
in speed is less than 7 mph (12 km/h).
The yellow indicator lamp goes out if reverse
gear is engaged. In this event, Blind Spot
Assist is no longer active.
The brightness of the indicator/warning
lamps is adjusted automatically according to
the ambient light.GWARNING
Blind Spot Assist is not active at speeds under
approximately 20 mph (30 km/h). The
indicator lamps in the exterior mirrors are
yellow. Vehicles in the monitoring range are
then not indicated.
Always pay attention to traffic conditions and
your surroundings. Otherwise, you may fail to
recognize dangers in time, cause an accident
and injure yourself and others.
Collision warning
If a vehicle is detected in the monitoring range
of Blind Spot Assist and you switch on the turn
signal, a double warning tone sounds. Red
warning lamp : flashes. If the turn signal
remains on, detected vehicles are indicated
by the flashing of red warning lamp :. There
are no further warning tones.
Switching on Blind Spot Assist
XMake sure that the radar sensor system
( Y page 210) and Blind Spot Assist
( Y page 207) are activated in the on-board
computer.XTurn the SmartKey to position 2 in the
ignition lock.
Warning lamps : light up red in the
exterior mirrors for approximately 1.5
seconds and then turn yellow.Lane Keeping Assist
Important safety notes
Lane Keeping Assist monitors the area in
front of your vehicle by means of a camera at
the top of the windshield. Lane Keeping Assist
detects lane markings on the road and warns
you before you leave your lane
unintentionally.
If you have chosen the (Y page 208) function
in the on-board computer and select as the
unit of measurement, Active Lane Keeping
Assist is active from speeds of 60 km/h. If
the display unit is selected, the assistance
range begins at 40 mph.
GWARNING
Lane Keeping Assist does not keep your
vehicle in its lane. It is only an aid and may
detect the lane markings on the road
incorrectly or not at all.
The system may be impaired or may not
function if:
R there is poor visibility, e.g. due to
insufficient illumination of the road, or due
to snow, rain, fog or spray.
R there is glare, e.g. from oncoming traffic,
the sun, or reflection from other vehicles.
R the windshield is dirty, fogged up or
covered, for instance by a sticker, in the
vicinity of the camera.
R several or no lane markings for a single lane
are present.
R the lane markings are worn away, dark or
covered up, e.g. by dirt or snow.
R the distance to the vehicle in front is too
small and the lane markings thus cannot be
detected.
R the lane markings on the road are unclear,
e.g. near roadworks.
R the lane markings change quickly, e.g.
lanes branch off, cross one another or
merge.
R the road is narrow and winding.
188Driving systemsDriving and parking

Lane Keeping Assist cannot detect road and
traffic conditions. It is not a substitute for
attentive driving. You are responsible for the
vehicle's speed, braking in good time, and
steering correctly. Always adapt your driving
style to suit the prevailing road and weather
conditions. Always pay attention to traffic
conditions and your surroundings. Otherwise,
you may fail to recognize dangers in time,
cause an accident and injure yourself and
others.
A warning can be given when a front wheel
passes over a lane marking. It will warn you
by means of intermittent vibration in the
steering wheel for up to 1.5 seconds.
Switching on Lane Keeping AssistXSymbol : appears in the multifunction
display.
Active Driving Assistance package
General notes
The Active Driving Assistance package
consists of DISTRONIC PLUS ( Y page 166),
Active Blind Spot Assist ( Y page 189) and
Active Lane Keeping Assist ( Y page 192).
Active Blind Spot Assist
Important safety notes
Active Blind Spot Assist uses a radar sensor
system to monitor the side areas of your
vehicle which are in back of the driver. A
warning display in the exterior mirrors draws
your attention to vehicles detected in the
monitored area. If you then switch on the
corresponding turn signal to change lane, you
will also receive an optical and audible
collision warning. If a risk of lateral collision
is detected, corrective braking may help you
avoid a collision. To support the course-
correcting brake application, Active Blind
Spot Assist also uses the forward-facing radar
sensor system. Active Blind Spot Assist
supports you from speeds of approximately
20 mph (30 km/h).GWARNING
Active Blind Spot Assist is only an aid, and
may detect vehicles/obstacles incorrectly or
not at all.
The system may be impaired or may not
function if:
R there is poor visibility, e.g. due to snow,
rain, fog or spray.
R the rear and/or front sensors are dirty.
Active Blind Spot Assist may not detect
narrow vehicles, such as motorcycles or
bicycles, or may only detect them too late. It
cannot detect vehicles that are overtaken at
a small distance and then enter the blind spot
area.
Active Blind Spot Assist cannot detect road
and traffic conditions. It is not a substitute for
attentive driving. You are responsible for the
vehicle's speed, braking in good time, and
steering correctly. Always adapt your driving
style to suit the prevailing road and weather
conditions. Always pay attention to traffic
conditions and your surroundings. Otherwise,
you may fail to recognize dangers in time,
cause an accident and injure yourself and
others.
i USA only:
This device has been approved by the FCC
as a “Vehicular Radar System”. The radar
sensor is intended for use in an automotive
radar system only. Removal, tampering, or
altering of the device will void any
warranties, and is not permitted by the
FCC. Do not tamper with, alter, or use in
any non-approved way.
Any unauthorized modification to this
device could void the user’s authority to
operate the equipment.
For Active Blind Spot Assist to assist you
when driving, the radar sensor system must
be activated ( Y page 210) and operational.
Driving systems189Driving and parkingZ

When your speed exceeds approximately
20 mph (30 km/h), warning lamp : lights up
red on the corresponding side whenever a
vehicle is detected in the blind spot
monitoring range. This warning is always
given when a vehicle enters the blind spot
monitoring range from behind or from the
side. When you are passing another vehicle,
the warning is emitted only if the difference
in speed is less than 7 mph (12 km/h).
The yellow indicator lamp goes out if reverse
gear is engaged. In this event, Active Blind
Spot Assist is no longer active.
The brightness of the indicator/warning
lamps is adjusted automatically according to
the ambient light.GWARNING
Active Blind Spot Assist is not active at speeds
lower than 20 mph (30 km/h). The indicator
lamps in the exterior mirrors are yellow.
Vehicles in the monitoring range are then not
indicated.
Always pay attention to traffic conditions and
your surroundings. Otherwise, you may fail to
recognize dangers in time, cause an accident
and injure yourself and others.
Visual and audible collision warnings
If you switch on the appropriate turn signals
and a vehicle is detected in the side
monitoring range, you will receive a visual and
acoustic collision warning. You will hear a
double warning tone and red warning
lamp : flashes. If the turn signal remains on,
vehicles detected are indicated by the
flashing of red warning lamp :. There are no
further warning tones.
Course-correcting brake application
If Active Blind Spot Assist detects a risk of a
lateral collision in the monitoring range, a
course-correcting brake application is carried
out. This is meant to assist you in avoiding a
collision.
The course-correcting brake application is
available in the range between 20 mph
(30 km/h) and 120 mph (200 km/h).
If a course-correcting brake application
occurs, red warning lamp : flashes in the
exterior mirror and the following is shown in
the multifunction display, for example:GWARNING
Active Blind Spot Assist is only an aid
designed to assist driving. It is not a substitute
for attentive driving. In some cases, the
course-correcting brake application is not
sufficient to avoid a collision. In such a case,
you must steer, brake or accelerate.
In very rare cases, the system may
erroneously detect a danger of collision in the
area of crash barriers or similar lane borders
and apply the brakes. Active Blind Spot Assist
does not detect all traffic situations and road
users. Always make sure that there is
sufficient distance on the side for other traffic
or obstacles. An inappropriate brake
application may be interrupted at any time if
you steer slightly in the opposite direction or
accelerate.
You are responsible for driving at appropriate
speeds, braking in good time, and steering
correctly. Always adapt your driving style to
suit the prevailing road and weather
conditions. Always pay attention to traffic
conditions and your surroundings. Otherwise,
you may fail to recognize dangers in time,
cause an accident and injure yourself and
others.
Driving systems191Driving and parkingZ

There will be either no or only a weak course-
correcting brake application if:
R there are vehicles or obstacles, e.g. crash
barriers, located on both sides of your
vehicle.
R a vehicle approaches you too closely at the
side.
R you have adopted a sporty driving style with
high cornering speeds.
R you clearly brake or accelerate.
R a driving safety system intervenes, e.g.
ESP ®
or PRE-SAFE ®
Brake.
R ESP ®
is switched off.
R a loss of tire pressure or a defective tire is
detected.
Switching on Active Blind Spot AssistXMake sure that the radar sensor system
( Y page 210) and Active Blind Spot Assist
( Y page 207) are activated in the on-board
computer.XTurn the SmartKey to position 2 in the
ignition lock.
Warning lamps : light up red in the
exterior mirrors for approximately 1.5
seconds and then turn yellow.
Active Lane Keeping Assist
Important safety notes
Active Lane Keeping Assist monitors the area
in front of your vehicle by means of a camera
at the top of the windshield. Active Lane
Keeping Assist detects lane markings on the
road and warns you before you leave your
lane unintentionally. If you do not react to the
warning, a lane-correcting application of the
brakes can bring the vehicle back into the
original lane.
:Active Lane Keeping Assist camera
If you have selected the Display Unit
Speed-/Odometer (Y page 208) function in
the on-board computer and select km as the
unit of measurement, Active Lane Keeping
Assist is active from speeds of 60 km/h. If
the miles display unit is selected, the
assistance range begins at 40 mph.
GWARNING
Active Lane Keeping Assist does not keep
your vehicle in its lane. It is only an aid and
may detect the lane markings on the road
incorrectly or not at all.
The system may be impaired or may not
function if:
R several or no lane markings for a single lane
are present.
R there is poor visibility, e.g. due to
insufficient illumination of the road, or due
to snow, rain, fog or spray.
R there is glare, e.g. from oncoming traffic,
the sun, or reflection from other vehicles.
R the windshield is dirty, fogged up or
covered, for instance by a sticker, in the
vicinity of the camera.
R the lane markings are worn away, dark or
covered up, e.g. by dirt or snow.
R the distance to the vehicle in front is too
small and the lane markings thus cannot be
detected.
R the lane markings on the road are unclear,
e.g. near roadworks.
192Driving systemsDriving and parking

Rthe lane markings change quickly, e.g.
lanes branch off, cross one another or
merge.
R the road is narrow and winding.
Active Lane Keeping Assist cannot detect
road and traffic conditions. It is not a
substitute for attentive driving. You are
responsible for the vehicle's speed, braking in
good time, and steering correctly. Always
adapt your driving style to suit the prevailing
road and weather conditions. Always pay
attention to traffic conditions and your
surroundings. Otherwise, you may fail to
recognize dangers in time, cause an accident
and injure yourself and others.
Warning vibration in the steering wheel
A warning can be given when a front wheel
passes over a lane marking. You will be
warned by means of intermittent vibration in
the steering wheel for up to 1.5 seconds.
In order that you are warned only when
necessary and in good time if you cross the
lane marking, the system recognizes certain
conditions and warns you accordingly.
The warning vibration occurs earlier if:
R you approach the outer lane marking on a
bend.
R the road has very wide lanes, e.g. a
freeway.
R the system recognizes solid lane markings.
The warning vibration occurs later if:
R the road has narrow lanes.
R you cut the corner on a bend.
No warning vibration occurs if:
R you clearly and actively steer, brake or
accelerate.
R you cut the corner on a sharp bend.
R a driving safety system intervenes, e.g.
ABS, BAS or ESP ®
.
R you switch on the turn signals. In this event,
the warnings are suppressed for a certain
period of time.Lane-correcting brake application
If you leave your lane under certain
circumstances the vehicle will brake briefly
on one side. This is meant to assist you in
bringing the vehicle back to the original lane.
This function is available in the range between
40 mph and 120 mph (60 km/h to
200 km/h).
A lane-correcting brake application can only
be made after driving over a solid,
recognizable lane marking. Before this, a
warning must be given by means of
intermittent vibration in the steering wheel.
In addition, a lane with lane markings on both
sides must be recognized. The brake
application also slightly reduces vehicle
speed.
If a lane-correcting brake application occurs,
the following, for example, appears in the
multifunction display:
i A further lane-correcting brake
application can only occur after your
vehicle has returned to the original lane.
GWARNING
Active Lane Keeping Assist does not keep
your vehicle in its lane. It is only an aid
designed to assist driving. It is not a substitute
for attentive driving. In some cases, the lane-
correcting brake application is not sufficient
to bring your vehicle back to the original lane.
In such cases, you must steer the vehicle
yourself to ensure that it does not leave the
lane.
Active Lane Keeping Assist does not detect
road and traffic conditions. Always make sure
that there is sufficient distance to the side for
other traffic or obstacles. In rare cases,
unclear markings or particular structures on
Driving systems193Driving and parkingZ

the roadway can be recognized as solid lane
markings. An inappropriate brake application,
e.g. after intentionally driving over a solid lane
marking, may be interrupted at any time by
steering slightly in the opposite direction.
Active Lane Keeping Assist cannot take
weather conditions into account.
You are responsible for the driving at
appropriate speeds, braking in good time, and
steering correctly. Always adapt your driving
style to suit the prevailing road and weather
conditions. Always pay attention to traffic
conditions and your surroundings. Otherwise,
you may fail to recognize dangers in time,
cause an accident and injure yourself and
others.
No lane-correcting brake application occurs
if:
R you clearly and actively steer, brake or
accelerate.
R you cut the corner on a sharp bend.
R you switch on the turn signals.
R a driving safety system intervenes, e.g.
ESP ®
, PRE-SAFE ®
Brake or Active Blind
Spot Assist.
R you have adopted a sporty driving style with
high cornering speeds or high rates of
acceleration.
R ESP ®
is switched off.
R the transmission is not in position D.
R a loss of tire pressure or a defective tire has
been detected and displayed.
Active Lane Keeping Assist does not detect
traffic situations or road users. An
inappropriate brake application may be
interrupted at any time if you:
R steer slightly in the opposite direction.
R use a turn signal.
R clearly brake or accelerate.A lane-correcting brake application is
interrupted automatically if:
R a driving safety system intervenes, e.g.
ESP ®
, PRE-SAFE ®
Brake or Active Blind
Spot Assist.
R lane markings can no longer be recognized.
Switching on Active Lane Keeping AssistXSwitch on Active Lane Keeping Assist using
the on-board computer ( Y page 207).
Symbol : appears in the multifunction
display.
If your speed exceeds 40 mph (60 km/h)
and lane markings are detected,
symbol : is highlighted. Active Lane
Keeping Assist is ready for use.194Driving systemsDriving and parking

! If the coolant temperature is too high a
display message is shown.
If the coolant temperature rises above
248 ‡(120 †), do not drive any further as
this could damage the engine.
Tachometer
The red band in the tachometer indicates the
engine's overrevving range.
! Do not drive in the overrevving range, as
this could damage the engine.
The fuel supply is interrupted to protect the
engine when the red band is reached.
Outside temperature display
The outside temperature display is in the
multifunction display ( Y page 198).
GWARNING
The outside temperature indicator is not
designed to serve as an ice-warning device
and is therefore unsuitable for that purpose.
Indicated temperatures just above the
freezing point do not guarantee that the road
surface is free of ice. The road may still be icy,
especially in wooded areas or on bridges.
Changes in the outside temperature are
displayed after a short delay.
Speedometer with segments
The segments in the speedometer indicate
which speed range is available.
Cruise control ( Y page 164) activated:
The segments light up from the stored speed
to the maximum speed.
DISTRONIC PLUS ( Y page 166) activated:
One or two segments in the set speed range
light up.
DISTRONIC PLUS detects a vehicle in front:
The segments between the speed of the
vehicle in front and the stored speed light up.
Operating the on-board computer
Overview
The on-board computer is activated as soon
as you turn the SmartKey to position 1 in the
ignition lock.
You can control the multifunction display and
the settings in the on-board computer using
the buttons on the multifunction steering
wheel.
:Multifunction display;To switch on the Voice Control System;
see the separate operating instructions=Right control panel?Left control panelABack buttonDisplays and operation197On-board computer and displaysZ