
ranties, 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.
i Canada only: This device complies with
RSS-210 of Industry Canada. Operation is
subject to the following two conditions:
1. This device may not cause interference,
and
2. This device must accept any interference
received, including interference that may
cause undesired operation of the device.
Removal, tampering, or altering of the device
will void any warranties, and is not permitted. 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.
Radar sensors The Active Blind Spot Assist radar sensors are
integrated into the front and rear bumpers and
behind a cover in the radiator trim. Make sure
that the bumpers and the cover in the radiator
grill are free of dirt, ice or slush. The sensors
must not be covered, for example by cycle racks or overhanging loads. Following an accident or
in the event of damage to the bumpers, have the
function of the radar sensors checked at a quali-
fied specialist workshop. Active Blind Spot
Assist may otherwise no longer work properly.
Monitoring area G
WARNING
Active Blind Spot Assist does not detect all
traffic situations and road users. There is a
risk of an accident.
Always make sure that there is sufficient dis-
tance on the side for other traffic or obstacles. At a distance of approximately 1.6 ft (0.5
m)0044
from the vehicle, Active Blind Spot Assist mon-
itors the area up to 10 ft (3 m) next to 0087and
behind 0043your vehicle, as shown in the picture.
In particular, the detection of obstacles can be
impaired if:
R there is dirt on the sensors or anything else
covering the sensors
R poor visibility, e.g. due to rain, snow or spray
Vehicles in the monitoring range are then not
reliably indicated.
Active Blind Spot Assist may not detect narrow
vehicles, such as motorcycles or bicycles, or
may only detect them too late.
If the lanes are narrow, vehicles driving in the
lane beyond the lane next to your vehicle may be
indicated, especially if the vehicles are not driv- ing in the middle of their lane. This may be the
case if there are vehicles at the inner edge of
your lane.
On very wide lanes, vehicles in the adjacent lane
may not be shown if they are too far away.
Due to the nature of the system:
R warnings may be issued in error when driving
close to crash barriers or similar solid lane
borders.
R warnings may be interrupted when driving
alongside particularly long vehicles, e.g.
trucks, for a prolonged time. Driving systems
195Driving and parking Z

Warning lamp
0043
Warning lamp
Active Blind Spot Assist is not operational at
speeds below approximately 20 mph (30 km/h). Vehicles in the monitoring range are then not
indicated.
If Active Blind Spot Assist is activated, warning
lamp 0043in the exterior mirrors lights up yellow
at speeds of up to 20 mph (30 km/h). At speeds
above 20 mph (30 km/h), the warning lamp
goes out and Active Blind Spot Assist is opera-
tional.
If a vehicle is detected within the monitoring
range at speeds above approximately 20 mph
(30 km/h), warning lamp 0043on the correspond-
ing side lights up red. This warning lamp always lights up when a vehicle enters the blind spot
monitoring range from behind or from the side.
When you overtake a vehicle, the warning only
occurs if the difference in speed is less than
7 mph (12 km/h).
If you select the reverse gear, Active Blind Spot Assist is not operational.
The brightness of the warning lamps is auto-
matically adapted to the brightness of the sur-
roundings.
Visual and acoustic collision warning
If you switch on the turn signals to change lanes
and a vehicle is detected in the side monitoring range, you receive a visual and acoustic collision
warning. You then hear a double warning tone
and red warning lamp 0043flashes. If the turn sig-
nal remains on, detected vehicles are indicated
by the flashing of red warning lamp 0043. There are
no further warning tones. Course-correcting brake application
If Active Blind Spot Assist detects a risk of a lat-
eral collision in the monitoring range, a course-
correcting brake application is carried out. This
is meant to assist you in avoiding a collision. G
WARNING
A course-correcting brake application cannot always prevent a collision. There is a risk of an
accident.
Always steer, brake or accelerate yourself,
especially if Active Blind Spot Assist warns
you or makes a course-correcting brake appli-
cation. Always maintain a safe distance at the sides.
If a course-correcting brake application occurs, red warning lamp 0043flashes in the exterior mir-
ror and a double warning tone sounds. In addi-
tion, a display underlining the danger of a side
collision appears in the multifunction display.
In very rare cases, the system may make an
inappropriate brake application. A course-cor-
recting brake application may be interrupted at
any time by countersteering slightly or acceler-
ating.
The course-correcting brake application is avail-
able in the speed range between 20 mph
(30 km/h) and 120 mph (200 km/h).
Either no braking application, or a course-cor-
recting brake application adapted to the driving situation occurs 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 Assist 196
Driving systemsDriving and parking

X
Make sure that Active Blind Spot Assist
(Y page 217) is activated in the on-board
computer.
X Turn the SmartKey to position 0048in the igni-
tion lock.
Warning lamps 0043in the exterior mirrors light
up red for approximately 1.5 seconds and
then turn yellow.
Towing a trailer
When you attach a trailer, make sure you have
correctly established the electrical connection.
This can be accomplished by checking the trailer
lighting. Active Blind Spot Assist is then deacti-
vated. The indicator lamp lights up yellow in the
exterior mirrors and the Active Blind Spot
Active Blind Spot
Asst. Not Available When Towing a Asst. Not Available When Towing a
Trailer See Operator's Manual
Trailer See Operator's Manual message
appears in the multifunction display.
Active Lane Keeping Assist General notes
Active Lane Keeping Assist monitors the area in
front of your vehicle by means of multifunction
camera 0043at the top of the windshield. Various
different areas to the front, rear and side of your vehicle are also monitored with the aid of the
radar sensor system. Active Lane Keeping
Assist detects lane markings on the road and
can warn you before you leave your lane unin-
tentionally. If you do not react to the warning, a
lane-correcting application of the brakes can
bring the vehicle back into the original lane.
This function is available in a speed range
between 40 mph and 120 mph (60 km/h and
200 km/h).
For Active Lane Keeping Assist to assist you
when driving, the radar sensor system must be
operational. Important safety notes
If you fail to adapt your driving style, Active Lane Keeping Assist can neither reduce the risk of
accident nor override the laws of physics. ActiveLane Keeping Assist cannot take into account
road, weather or traffic conditions. Active Lane
Keeping Assist is only an aid. You are responsi-
ble for the distance to the vehicle in front, for
vehicle speed, for braking in good time and for
staying in your lane.
Active Lane Keeping Assist cannot continuously
keep your vehicle in its lane. G
WARNING
Active Lane Keeping Assist cannot always
clearly detect lane markings.
In such cases, Active Lane Keeping Assist
can:
R give an unnecessary warning and then
make a course-correcting brake application
R neither give a warning nor intervene
There is a risk of an accident.
Always pay particular attention to the traffic
situation and keep within the lane, especially
if Active Lane Keeping Assist alerts you. Ter-
minate the intervention in a non-critical driv-
ing situation.
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 heavy spray
R there is glare, e.g. from oncoming traffic, the
sun or reflection from other vehicles (e.g. if
the road surface is wet)
R the windshield is dirty, fogged up, damaged or
covered, for instance by a sticker, in the vicin- ity of the camera
R there are no or several unclear lane markings
for one lane, e.g. roadworks
R the lane markings are worn away, dark or cov-
ered up, e.g. by dirt or snow
R the distance to the vehicle in front is too short
and thus the lane markings cannot be detec-
ted
R the lane markings change quickly, e.g. lanes
branch off, cross one another or merge
R the road is narrow and winding Driving systems
197Driving and parking Z

R
there are highly variable shade conditions on
the roadway
R no vehicle is detected in the adjacent lane and
there are broken lane markings
Warning vibration in the steering wheel
A warning may be given if 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 second s.
In orde r that you are warned only when neces-
sary and in good time if you cross the lane mark-
ing, the system detects 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 detects solid lane markings
The warning vibration occurs later if:
R the road has narrow lanes
R you cut the corner on a bend
Lane-correcting brake application G
WARNING
A lane-correcting brake application cannot
always bring the vehicle back into the original lane. There is a risk of an accident.
Always steer, brake or accelerate yourself,
especially if Active Lane Keeping Assist warns
you or makes a lane-correcting brake appli-
cation. G
WARNING
Active Lane Keeping Assist does not detect
traffic conditions or road users. In very rare
cases, the system may make an inappropriate brake application, e.g. after intentionally driv-
ing over a solid lane marking. There is a risk of an accident.
An inappropriate brake application may be
interrupted at any time if you steer slightly in
the opposite direction. Always make sure that
there is sufficient distance on the side for
other traffic or obstacles. If you leave your lane, under certain circumstan-
ces the vehicle will brake briefly on one side.
This is meant to assist you in bringing the vehicle
back to the original lane.
If a lane-correcting brake application occurs,
display 0043appears in the multifunction display.
A lane-correcting brake application can be made
after driving over a solid or broken 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 have been detected.
In the case of a broken lane marking being
detected, a lane-correcting brake application
can only be made if a vehicle has been detected
in the adjacent lane. The following vehicles can
have an influence on brake application: oncom- ing traffic, vehicles that are overtaking and vehi-cles that are driving parallel to your vehicle.
i A further lane-correcting brake application
can only occur after your vehicle has returned
to the original lane.
No lane-correcting brake application occurs if:
R you clearly and actively steer, brake or accel-
erate
R you cut the corner on a sharp bend
R you have switched on the turn signal
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 accel-
eration
R ESP ®
is switched off
R the transmission is not in position 005B
R on vehicles with a trailer tow hitch, the elec-
trical connection to the trailer has been cor-
rectly established 198
Driving systemsDriving and parking

R
an obstacle has been detected in the lane in
which you are driving
R when a loss of tire pressure or a defective tire
has been detected and displayed
There is a possibility that the Active Lane Keep- ing Assist could misjudge the given traffic sit-
uation. An inappropriate brake application may
be interrupted at any time if you:
R steer slightly in the opposite direction
R switch on the turn signal
R clearly brake or accelerate
A lane-correcting brake application is interrup-
ted automatically if:
R a driving safety system intervenes, e.g. ESP ®
,
PRE-SAFE ®
Brake or Active Blind Spot Assist
R lane markings are no longer detected
Switching on Active Lane Keeping Assist X Switch on Active Lane Keeping Assist using
the on-board computer; to do so, select
Standard
Standard orAdaptive Adaptive (Ypage 217).
If you drive at speeds above 40 mph
(60 km/h) and lane markings are detected,
the lines in the assistance graphic are shown in green (Y page 216). Active Lane Keeping
Assist is ready for use.
If Standard Standard is selected, no warning vibration
occurs if:
R you switch on the turn signals. In this event,
the warnings are suppressed for a certain
period of time.
R a driving safety system intervenes, such as
ABS, BAS or ESP ®
.
When Adaptive
Adaptive is selected, no warning vibra-
tion occurs if:
R you switch on the turn signals. In this event,
the warnings are suppressed for a certain
period of time.
R a driving safety system intervenes, e.g.
ABS, BAS or ESP ®
.
R you accelerate hard, e.g. kickdown.
R you brake hard.
R you steer actively, e.g. swerve to avoid an
obstacle or change lanes quickly.
R you cut the corner on a sharp bend.
Towing a trailer
When you attach a trailer, make sure you have
correctly established the electrical connection.
This can be accomplished by checking the trailer lighting. Lane-correcting brake application does
not take place when towing a trailer. Active Lane
Keeping Assist is not activated and the lines in
the assistance graphic are gray. Towing a trailer
Important safety notes
G
WARNING
Installing an unsuitable ball coupling may
overload the trailer tow hitch and the rear
axle. This is particularly likely in the case of
longer or differently angled ball couplings.
Consequently, the driving characteristics may
be significantly impaired and the trailer may
detach. This presents the risk of an accident
or even fatal injuries!
Install only a ball coupling that adheres to the permissible dimensions and is designed for
your intended purpose for towing a trailer. Do
not make any changes to the ball coupling or the trailer tow hitch.
You will find the values approved by the manu-
facturer on the vehicle identification plates and
those for the towing vehicle under "Technical
data" (Y page 367). G
WARNING
If the ball coupling is not installed correctly or not secured with the bolt provided and the
corresponding spring cotter, the trailer may
come loose. There is a risk of an accident.
Always install and secure the ball coupling as
described. Before every journey, ensure that
the ball coupling is secured with the bolt and
the corresponding spring cotter. G
WARNING
When the vehicle/trailer combination begins
to lurch, you could lose control of it. The vehi- cle/trailer combination could even rollover.
There is a risk of an accident.
On no account should you attempt to
straighten up the vehicle/trailer combination
by increasing the speed. Reduce vehicle Towing a trailer
199Driving and parking
Z

speed and do not countersteer. Apply the
brake as necessary.
Please observe the manufacturer's operating
instructions for the trailer coupling if a detach-
able trailer coupling is used.
Couple and uncouple the trailer carefully. If you do not couple the trailer to the towing vehicle
correctly, the trailer could become detached.
Make sure that the following values are not
exceeded:
R the permissible trailer drawbar noseweight
R the permissible trailer load
R the permissible rear axle load of the towing
vehicle
R the maximum permissible gross vehicle
weight of both the towing vehicle and the
trailer
The applicable permissible values, which must
not be exceeded, can be found:
R in the vehicle documents
R on the identification plates for the trailer tow
hitch and the trailer
R on the vehicle identification plate
If the values differ, the lowest value applies.
When towing a trailer, your vehicle's handling
characteristics will be different in comparison
with when driving without a trailer.
The vehicle/trailer combination:
R is heavier
R is restricted in its acceleration and gradient-
climbing capability
R has an increased braking distance
R is affected more by strong crosswinds
R demands more sensitive steering
R has a larger turning circle
This could impair the handling characteristics.
When towing a trailer, always adjust your speed to the current road and weather conditions. Do
not exceed the maximum permissible speed for
your vehicle/trailer combination. Notes on towing a trailer
General notes !
If you have a trailer tow hitch retrofitted,
changes to the cooling system and drive train may be necessary, depending on the vehicle
type.
If you have a trailer tow hitch retrofitted,
observe the anchorage points on the chassis
frame.
R Do not exceed the legally prescribed maxi-
mum speed for vehicle/trailer combinations
in the relevant country.
This lowers the risk of an accident.
R Only install an approved trailer coupling on
your vehicle.
More information on availability and installa-
tion can be obtained at any qualified special-
ist workshop.
R The bumpers of your vehicle are not suitable
for installing detachable trailer couplings.
R Do not install hired trailer couplings or other
detachable trailer couplings on the bumpers
of your vehicle.
R If you no longer need the ball coupling,
remove it from the ball coupling recess. This
will reduce the risk of damage to the ball cou- pling.
When towing a trailer, set the tire pressure on
the rear axle of the towing vehicle for the max-
imum load. You will find the values in the tire
pressure table in the fuel filler flap of the vehicle
(Y page 346).
Please note that when towing a trailer, the fol-
lowing driving systems have limited availability
or are not available at all:
R Parking Assist PARKTRONIC (Y page 173)
R Blind Spot Assist (Y page 191)
R Active Lane Keeping Assist (Y page 197)
On vehicles without level control, the height of
the ball coupling will alter according to the load
placed on the vehicle. If necessary, use a trailer
with a height-adjustable drawbar.
You will find installing dimensions and loads
under "Technical data" (Y page 367).
Driving tips Also observe the notes on pulling away with a
trailer (Y
page 130).
The maximum permissible speed for vehicle/
trailer combinations depends on the type of
trailer. Before beginning the journey, check the
trailer's documents to see what the maximum
permissible speed is for your trailer. Observe the 200
Towing a trailerDriving and parking

X
Establish the electrical connection between
the vehicle and the trailer.
X Check that the trailer lighting system is work-
ing.
X Push the combination switch upwards/down-
wards and check whether the corresponding
turn signal on the trailer flashes.
A trailer that is connected is recognized only
when the electrical connection is established
correctly and when the lighting system is work-
ing properly. The function of other systems also depends on this, for example:
R ESP ®
R Parking Assist PARKTRONIC
R Active Parking Assist
R Parking Package with rear view camera
R Active Blind Spot Assist
R Active Lane Keeping Assist
i Vehicles with the AIRMATIC Package: if you
couple up a trailer, the vehicle always remains
at normal level. When coupling up a trailer,
please observe the following:
R If the normal level has not been set man-
ually, the vehicle is automatically lowered
to normal level. This is the case if a speed of
5 mph (8 km/h) is reached.
R The Sport drive program is not available.
These restrictions apply to all accessories
powered through a connection to the trailer
power socket of your vehicle, e.g. a bicycle
carrier.
Observe the maximum permissible trailer
dimensions (width and length).
Most U.S. states and all Canadian provinces
require by law: R Safety chains between the towing vehicle and
the trailer. The chains should be cross-woundunder the trailer drawbar. They must be fas-
tened to the vehicle's trailer coupling, not to
the bumper or the axle.
Leave enough play in the chains to make tight
cornering possible.
R A separate brake system for certain types of
trailer.
R Safety switch for braked trailers. Check the
specific legal requirements applicable to your
state.
If the trailer becomes detached from the tow-
ing vehicle, the safety feature triggers the
trailer brakes. Towing a trailer
There are numerous legal requirements con-
cerning the towing of a trailer, e.g. speed restric- tions. Make sure that your car/trailer combina-
tion complies with the local regulations:
R in your place of residence
R in the location to which you are driving
The police and local authorities can provide reli- able information.
Observe the following when towing a trailer:
R To gain driving experience and to become
accustomed to the new handling characteris-
tics, you should practice the following in a
traffic-free location:
- cornering
- stopping
- backing up
R Before driving, check:
- trailer tow hitch
- safety switch for braked trailers
- safety chains
- electrical connections
- lights
- wheels
R Adjust the exterior mirrors to provide an
unobstructed view of the rear section of the
trailer.
R If the trailer has electronically controlled
brakes, pull away carefully. Brake manually
using the brake controller and check whether
the brakes function correctly.
R Secure any objects on the trailer to prevent
the cargo from slipping when the vehicle is in
motion.
R When you couple up a trailer, check at regular
intervals that the load is firmly secured. If the trailer is equipped with trailer lights and
brakes, check the trailer to ensure that these
are working.
R Bear in mind that the handling will be less
stable when towing a trailer than when driving
without one. Avoid sudden steering move-
ments.
R The vehicle/trailer combination is heavier,
accelerates more slowly, has a decreased
gradient climbing capability and a longer
braking distance.
It is more susceptible to side winds and
requires more careful steering. Towing a trailer
203Driving and parking Z

Assistance menu
Introduction Depending on the equipment installed in the
vehicle, you have the following options in the
DriveAssist
DriveAssist menu:
R Displaying the assistance graphic
(Y page 216)
R Activating/deactivating the Traffic Sign
Assist display (Y page 216)
R Activating or deactivating Active Steering
Assist (Y page 216)
R Activating/deactivating Active Brake Assist
(Y page 216)
R Activating/deactivating Active Brake Assist
with cross-traffic function (Y page 216)
R Activating/deactivating ATTENTION ASSIST
(Y page 217)
R Activating/deactivating Blind Spot Assist or
Active Blind Spot Assist (Y page 217)
R Activating/deactivating Lane Keeping Assist
or Active Lane Keeping Assist (Y page 217)
Displaying the assistance graphic X
Press the 0059or0065 button on the steering
wheel to select the DriveAssist
DriveAssist menu.
X Press 0063or0064 to select Assistance
Assistance
Graphic Graphic.
X Confirm by pressing 0076on the steering
wheel.
The multifunction display shows the Active
Distance Assist DISTRONIC distance display
on the assistant display.
The assistance graphic displays the status of
and information from the following driving
systems or driving safety systems:
R Traffic Sign Assist (Y page 190)
R Active Distance Assist DISTRONIC
(Y page 157)
R Active Brake Assist (Y page 65)
R Active Brake Assist with cross-traffic func-
tion (Y page 70) R
ATTENTION ASSIST (Y page 189)
R Lane Keeping Assist (Y page 193) or Active
Lane Keeping Assist (Y page 197)
R DSR (Y page 167)
X Press 0064to display the ATTENTION ASSIST
assessment.
Traffic Sign Assist You can switch the Traffic Sign Assist message
function on or off in the
Traffic TrafficSign
SignAssist
Assist
menu. When the function is activated, detected traffic signs and information appear in the mul-
tifunction display for five seconds.
X Press the 0059or0065 button on the steering
wheel to select the DriveAssist DriveAssistmenu.
X Press the 0063or0064 button to select
Traffic Sign Assist
Traffic Sign Assist .
X Confirm by pressing 0076on the steering
wheel.
The current selection appears.
X To activate/deactivate the message func-
tion: press the 0076button again.
For further information about Traffic Sign Assist, see (Y page 190).
Activating or deactivating Active Steer- ing Assist X
Press the 0059or0065 button on the steering
wheel to select the DriveAssist DriveAssistmenu.
X Press the 0063or0064 button to select
Active Steering Assist
Active Steering Assist .
X Confirm by pressing 0076on the steering
wheel.
The current selection appears.
X To activate/deactivate: press the0076but-
ton again.
When Active Steering Assist is activated, the
multifunction display shows the Active Active
Steering Assist
Steering Assist On
Onmessage.
Further information about Active Distance
Assist DISTRONIC with Active Steering Assist
(Y page 164).
Activating/deactivating Active Brake
Assist You can use these functions to activate/deac-
tivate Active Brake Assist or, on vehicles with
the Driving Assistance package, to activate or216
Menus and sub
menusOn-board computer and displays