
The evaluation of your attention level is deleted
and restarted when continuing the journey, if:
R you switch off the engine
R you take off your seat belt and open the driv-
er's door, e.g. for a change of drivers or to
take a break
Displaying the attention level You can have current status information dis-
played in the assistance menu (Y page 220) of
the on-board computer.
X Select the assistance graphics display for
ATTENTION ASSIST using the on-board com-
puter (Y page 220).
The following information is displayed:
R the length of the journey since the last break
R the attention level determined by ATTENTION
ASSIST, displayed in a bar display in five levels from high to low
R if ATTENTION ASSIST is unable to calculate
the attention level and cannot output a warn-
ing, the System suspended
System suspended message
appears. The bar display then changes the
display, e.g. if you are driving at a speed below
60 km/h or above 200 km/h.
Activating ATTENTION ASSIST X
Activate ATTENTION ASSIST using the on-
board computer (Y page 222).
The system determines the attention level of
the driver depending on the setting selected:
Standard selected: the sensitivity with which
the system determines the attention level is set
to normal.
Sensitive selected: the sensitivity is set higher.
The attention level detected by ATTENTION
ASSIST is adapted accordingly and the driver is
warned earlier.
When ATTENTION ASSIST is deactivated, the
À symbol and OFF appear in the multifunc-
tion display in the assistance graphics display
when the engine is running. When ATTENTION ASSIST has been deactivated,
it is automatically reactivated after the engine
has been switched off. The sensitivity selected
corresponds to the last selection activated
(standard/sensitive).
Warning in the multifunction display If fatigue or increasing lapses in concentration
are detected, a warning appears in the multi-
function display:
Attention AttentionAssist:
Assist:Take
Take a
a
break!
break!
In addition to the message shown in the multi-
function display, you will then hear a warning
tone.
X If necessary, take a break.
X Confirm the message by pressing the a
button on the steering wheel.
On long journeys, take regular breaks in good
time to allow yourself to rest. If you do not take a break, you will be warned again after
15 minutes at the earliest. This will only happen
if ATTENTION ASSIST still detects typical indi-
cators of fatigue or increasing lapses in concen- tration.
Vehicles with COMAND Online: if a warning is
output in the multifunction display, a service
station search is performed in the multimedia
system. You can select a service station and
navigation to this service station will then begin. This function can be activated and deactivated
in the multimedia system. Traffic Sign Assist
General notes Traffic Sign Assist displays the maximum speed
permitted and overtaking restrictions to the
driver in the instrument cluster. Driving onto a Driving systems
197Driving and parking Z

Activating Blind Spot Assist
X Make sure that Blind Spot Assist
(Y page 222) is activated in the on-board
computer.
X Turn the key to position 2in the ignition lock.
Warning lamps :in the exterior mirrors light
up red for approximately 1.5 seconds and
then turn yellow.
Towing a trailer
If you couple up a trailer, make sure that you
have correctly established the electrical con-
nection. This can be accomplished by checking
the trailer lighting. Blind Spot Assist is then
deactivated. The indicator lamps in the exterior
mirrors light up yellow and the Blind Spot
Blind Spot
Assist not available when towing a
Assist not available when towing a
trailer See Owner's Manual
trailer See Owner's Manual message
appears in the multifunction display.
i You can deactivate the indicator lamps in
the exterior mirrors.
To do so, you will need to deactivate Blind
Spot Assist if:
R the key is in position 2in the ignition lock
R the engine is not running
R the electrical connection to the trailer has
been established
Lane Keeping Assist General notes
Lane Keeping Assist monitors the area in front of
your vehicle by means of camera :at the top of
the windscreen. Lane Keeping Assist detects
lane markings on the road and can warn you
before you leave your lane unintentionally.
This function is available within a speed range
between 60 km/h and 200 km/h. A warning may be given if a front wheel passes
over a lane marking. It will warn you by means of
intermittent vibration through the steering
wheel for up to 1.5 seconds.
Important safety notes G
WARNING
Lane Keeping Assist cannot always clearly
identify lane markings.
In these cases, Lane Keeping Assist may:
R give an unnecessary warning
R not give a warning
There is a risk of an accident.
Always pay particular attention to the traffic
situation and keep in lane, especially if Lane
Keeping Assist alerts you. G
WARNING
The Lane Keeping Assist warning does not
return the vehicle to the original lane. There is a risk of an accident.
Always steer, apply the brakes or accelerate
the vehicle yourself, especially if Lane Keep-
ing Assist alerts you.
If you fail to adapt your driving style, Lane Keep-
ing Assist can neither reduce the risk of an acci-
dent nor override the laws of physics. Lane
Keeping Assist cannot take into account road,
weather or traffic conditions. Lane Keeping
Assist is only an aid. You are responsible for the distance to the vehicle in front, for vehicle
speed, for braking in good time, and for staying
in lane.
Lane Keeping Assist does not keep your vehicle in its lane.
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 (e.g. if
the road surface is wet)
R the windscreen is dirty, misted up, damaged
or covered, for instance by a sticker, in the
vicinity of the camera
R no or several, unclear lane markings are pres-
ent for one lane, e.g. in a construction area 202
Driving systemsDriving and pa
rking

Active Lane Keeping Assist
General notes
Active Lane Keeping Assist monitors the area in
front of your vehicle by means of multifunction
camera :at the top of the windscreen. 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 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 an
accident nor override the laws of physics. Active Lane Keeping Assist cannot take account of
road and weather conditions. It may not detect
traffic situations. Active Lane Keeping Assist is
only an aid. You are responsible for the distance to the vehicle in front, for vehicle speed, for
braking in good time and for staying in 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
to the vehicle
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 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 windscreen is dirty, misted up, damaged
or covered, for instance by a sticker, in the
vicinity of the camera
R the radar sensors in the front or rear bumpers
or the radiator trim are dirty, e.g. obscured by snow
R no or several, unclear lane markings are pres-
ent for one lane, e.g. in a construction area
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 small
and the lane markings thus 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
R there are highly variable shade conditions on
the road
If no vehicle is detected in the adjacent lane and broken lane markings are detected, no lane-cor-
recting brake application is made.
Warning vibration through 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 seconds. 206
Driving systemsDriving and pa
rking

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 only detects traf-
fic conditions or road users to a limited
extent. In very rare cases, the system may
make an inappropriate brake application, e.g. after intentionally driving 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 to 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 intended to help you return the vehicle to
the original lane.
If a lane-correcting brake application occurs,
display :appears in the multifunction display.
A lane-correcting brake application can be made
after driving over a lane marking detected as
being solid or broken. Before this, a warning
must have been issued by means of intermittent
vibration through the steering wheel. In addi-
tion, a lane with lane markings on both sides
must be 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 adopted a sporty driving style with
high cornering speeds or high rates of accel-
eration
R you have switched on the turn signal
R a driving safety system intervenes, such as
ESP ®
, PRE-SAFE ®
Brake or Active Blind Spot
Assist
R ESP ®
is deactivated
R the transmission is not in position D
R on vehicles with a trailer tow hitch, the elec-
trical connection to the trailer has been cor-
rectly established
R an obstacle has been detected in the lane in
which you are driving
R a loss of tyre pressure or a defective tyre 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:
R you steer slightly in the opposite direction
R you switch on the turn signal
R you clearly brake or accelerate
A lane-correcting brake application is interrup-
ted automatically if:
R a driving safety system intervenes, such as
ESP ®
, PRE-SAFE ®
Brake or Active Blind Spot
Assist
R lane markings are no longer detected
Activating Active Lane Keeping Assist
X Activate Active Lane Keeping Assist using the
on-board computer; to do so, select Stand‐
Stand‐
ard ard orAdaptive
Adaptive (Ypage 222).
If you drive at speeds above 60 km/h and lane
markings are detected, the lines in the assis- tance graphic display (Y page 220) are
shown in green. Active Lane Keeping Assist is
ready for use.
If Standard Standard is selected, no warning vibration
occurs if: Driving systems
207Driving and parking Z

the power output of the engine, and conse-
quently the vehicle's gradient-climbing capa-
bility, decrease with increasing altitude.
Folding the ball coupling in/out
Folding out the ball coupling G
WARNING
If the ball coupling is not correctly engaged,
the trailer can detach. There is a risk of an
accident.
Always engage the ball coupling as described. G
WARNING
If you release the ball coupling or it does not
engage correctly when folding in, it will swing out. Within pivoting range of the ball coupling,
there is an increased risk of an accident and
injury.
Only release the ball coupling if the pivoting
range is unobstructed. Always make sure that the ball coupling engages when folding in.
Before you can tow a trailer with your vehicle,
you must fold out the ball coupling. The release wheel is located behind the left-
hand side trim panel in the boot.
Opening the cover:
X Turn handle :around anti-clockwise and
fold cover ;down. Unlocking and folding out the ball coupling:
X Pull out release wheel ?.
X Turn release wheel ?anti-clockwise until the
ball coupling releases and folds out from
under the rear bumper. Indicator lamp =
flashes. X
Pull the ball coupling in the direction of the
arrow until it engages in a vertical position.
The trailer power socket is integrated into the ball coupling and swivels out with it.
Indicator lamp =goes out.
The multifunction display shows the
Trailer hitch Check lock mech. Trailer hitch Check lock mech. mes-
sage until the ball coupling is engaged.
X Remove the protective covering from the ball
coupling and store it in a safe place.
X Make sure that the ball of the ball coupling is
clean and greased.
HYBRID vehicles : make sure that you read the
"HYBRID" Supplement included in the vehicle
literature. Otherwise, you may not recognise
dangers. 210
Towing a trailerDriving an
d parking

Folding in the ball coupling
i
Fold the ball coupling back in if you are not
using the trailer tow hitch.
X Place the protective covering on the ball cou-
pling.
Opening the cover: X Turn handle :anti-clockwise and fold down
cover ;.
Unlocking and lowering the ball coupling:
X Pull out release wheel ?.
X Turn release wheel ?anti-clockwise.
The ball coupling unlocks and lowers. Indica-
tor lamp =flashes.
X Press the ball coupling in the direction of the
arrow until it engages behind the bumper.
Indicator lamp =goes out and the message
in the multifunction display disappears. Coupling up a trailer
X Make sure that the transmission is in position
P .
X Apply the parking brake.
X Position the trailer horizontally behind the
vehicle.
X Couple up the trailer.
X Establish the electric connection between the
vehicle and the trailer.
X Check that the trailer lighting system is work-
ing.
A connected trailer is only recognised when
the electrical connection is established cor-
rectly and when the lighting system is working
properly. The function of other systems, such
as ESP ®
, PARKTRONIC and Active Parking
Assist also depends on this. Uncoupling a trailer
G
WARNING
If you uncouple a trailer with an engaged over- run brake, you could trap your hand between
the vehicle and the trailer drawbar. This poses a risk of injury.
Do not uncouple a trailer with an engaged
overrun brake. G
WARNING
Vehicles with level control:
If you disconnect the trailer cable, the vehicle is lowered. This can cause you or others to
become trapped between the vehicle body
and tyres, or underneath the vehicle. This
poses a risk of injury.
Make sure that no-one is in the immediate
vicinity of the wheel arch or underneath the
vehicle when disconnecting the trailer cable.
! Do not disconnect a trailer with an engaged
overrun brake. Otherwise, your vehicle could
be damaged by the rebounding of the overrun
brake.
X Make sure that the transmission is in position
P.
X Apply the parking brake.
X Secure the trailer against rolling away.
X Remove the trailer cable and decouple the
trailer. Trailer power supply
! You can connect accessories to the perma-
nent power supply up to a maximum of 240 W.
You cannot charge a trailer battery using the
power supply.
X To switch the connected power supply on
or off: turn the key in the ignition lock to
position 2or 0respectively (Y page 139).
When it leaves the factory, your vehicle's trailer
socket is equipped with a permanent power
supply and a power supply that is switched on
via the ignition lock.
The permanent power supply is supplied via
trailer socket pin 9.
The power supply that is switched on via the
ignition lock is supplied via trailer socket pin 10.
The trailer's permanent power supply is
switched off in the event of low vehicle supply
voltage and after six hours at the latest.
You can find more information about fitting the
trailer electrics at a qualified specialist work-
shop. Towing a trailer
211Driving and parking Z

Under normal operating conditions and with the
specified coolant level, the coolant temperature
may rise to 120 †.
At high outside temperatures and when driving
uphill, the coolant temperature may rise to the
end of the scale. Operating the on-board computer
Overview :
Multifunction display
; Switches on voice-operated control for nav-
igation or LINGUATRONIC
= Right control panel
? Left control panel
A Back button
X To activate the on-board computer: turn
the key to position 1in 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.
You can find further information on LINGUA-
TRONIC in the separate operating instruc-
tions in vehicles with a COMAND Online mul-
timedia system.
You can find further information on voice-
operated control for navigation in the manu-
facturer's operating instructions in vehicles
with an Audio 20 multimedia system. Left control panel =
; R
Calls up the menu and menu bar 9
: Press briefly:
R Scrolls through lists
R Selects a submenu or function
R In the Audio Audio menu: selects the
previous or next station, when the preset list or station list is active,
or an audio track or video scene
R In the Tel Tel(telephone) menu:
switches to the phone book and
selects a name or telephone num-
ber 9
: Press and hold:
R
In the Audio Audio menu: selects a pre-
set list or a station list in the
desired frequency range, or an
audio track or video scene using
rapid scrolling
R In the Tel Tel(Telephone) menu:
starts rapid scrolling if the phone
book is open a R
Confirms the selection or display
message
R In the Tel Tel(Telephone) menu:
switches to the telephone book
and starts dialling the selected
number Right control panel
~ R
Rejects or ends a call
R Exits the telephone book/redial
memory 6 R
Makes or accepts a call
R Switches to the redial memory W
X R
Adjusts the volume 8 R
Mute 214
Displays and operationOn-board computer and displays

Back button
% Press briefly:
R Back
R Switches off voice-operated con-
trol for navigation or LINGUA-
TRONIC
R Hides display messages or calls up
the last Trip Tripmenu function used
R Exits the telephone book/redial
memory % Press and hold:
R
Calls up the standard display in the
Trip
Trip menu Multifunction display
:
Text field
; Menu bar
= Drive program
? Transmission position
A Permanent display: outside temperature or
speed
X To display menu bar ;:press the =
or ; button on the steering wheel.
If you do not press the buttons any longer,
menu bar ;is faded out after a few seconds.
Text field :shows the selected menu or sub-
menu as well as display messages.
Possible displays in the multifunction dis-
play:
R ZGearshift recommendation for manual
transmission (Y page 147) or for automatic
transmission (shifting manually)
(Y page 151)
R j Active Parking Assist (Y page 183)
R ¯ Cruise control (Y page 163) R
È SPEEDTRONIC (Y page 165)
R _ Adaptive Highbeam Assist Plus
(Y page 117)
R ¤ ECO start/stop function (Y page 142)
R ë HOLD function (Y page 177)
R 120 km/h! 120 km/h! Maximum permissible speed
exceeded (only for certain countries) Menus and submenus
Menu overview
Press the =or; button on the steering
wheel to call up the menu bar and select a menu.
Operating the on-board computer (Y page 214).
Depending on the equipment fitted in the vehi-
cle, you can call up the following menus:
R Trip Trip menu (Y page 215)
R Navi
Navi menu (navigation instructions)
(Y page 217)
R Audio
Audio menu (Y page 218)
R Tel
Tel menu (telephone) (Y page 219)
R Assist.
Assist. menu (assistance) (Y page 220)
R Serv.
Serv. menu (Y page 222)
R Settings
Settings menu (settings) (Y page 223)
The displays are dependent on the multimedia
system. This is why the displays for the Audio Audio,
Navi
Navi andTel
Tel menus may differ slightly to those
in your vehicle. Trip menu
Standard display X
Press and hold the %button on the steer-
ing wheel until the Trip
Tripmenu with trip
meter :and total distance recorder ;
appears. Menus and submenus
215On-board computer and displays Z