2012 MERCEDES-BENZ A CLASS lane assist

Blind Spot Assist is only an aid. It may fail to
detect
some vehicles and is no substitute for
attentive driving.
General 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
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. For this pur-
pose, Blind Spot Assist uses sensors in the
rear bumper.
The radar sensor system is switched off auto-
matically in the vicinity of radio telescope
facilities ( Y page 350).
For Blind Spot Assist to assist you when driv-
ing, the radar sensor system must be:
R activated(Y page 223)
R operational
i In some countries you must deactivate
the radar sensor system ( Y page 223).
For further information about the radar sen-
sor system; see ( Y page 350).
Monitoring range of the sensors
In particular, the detection of obstacles can
be impaired in the case of:
R dirt on the sensors or anything else cover-
ing the sensors
R poor visibility, e.g. due to fog, heavy rain or
snow
R a narrow vehicle travelling in front, e.g. a
motorcycle or a bicycle
R very wide lanes
R narrow lanes
R vehicles not driving in the middle of their
lane
R barriers or other road boundaries
Vehicles in the monitoring range are then not
indicated. Blind Spot Assist monitors the area up to
3.0

m behind your vehicle and directly next to
your vehicle, as shown in the diagram. For this
purpose, Blind Spot Assist uses radar sensors
in the rear bumper.
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
driving in the middle of their lane. This may
be the case if the vehicles are driving on the
inner side of their lane.
Due to the nature of the system:
R warnings may be issued in error when driv-
ing close to crash barriers or similar solid
lane borders.
R warnings may be interrupted when driving
alongside particularly long vehicles, for
example lorries, for a prolonged time.
The two sensors for Blind Spot Assist are
integrated into the sides of the rear bumper.
Make sure that the bumper is free of dirt, ice
or slush in the vicinity of the sensors. The
radar sensors must not be covered, for exam-
ple by cycle racks or overhanging loads. Fol-
lowing a severe impact or in the event of dam-
age to the bumpers, have the function of the
radar sensors checked at a qualified special-
ist workshop. Blind Spot Assist may other-
wise not work properly. 198
Driving systems
Driving and parking

Indicator and warning display
Blind
Spot Assist is not active at speeds below
approximately 30 km/h. Vehicles in the mon-
itoring range are then not indicated. :
Yellow indicator lamp/red warning lamp
If Blind Spot Assist is switched on, indicator
lamp : in the exterior mirrors lights up yel-
low up to a speed of

30 km/h. At speeds
above 30 km/h, the indicator lamp goes out
and Blind Spot Assist is operational.
If a vehicle is detected within the monitoring
range of Blind Spot Assist at speeds above
30 km/h, warning lamp : on the corre-
sponding side lights up in red. This warning
always occurs 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 12 km/h.
The yellow indicator lamp goes out if reverse
gear is engaged. Blind Spot Assist is then
deactivated.
The brightness of the indicator/warning
lamps is adjusted automatically according to
the ambient light.
Collision warning
If a vehicle is detected in the monitoring range
of Blind Spot Assist and you switch on the
corresponding 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. Activating Blind Spot Assist
X
Make sure that the radar sensor system
(Y page 223) and Blind Spot Assist
(Y page

219) are activated in the on-board
computer.
X Turn the key to position 2 in 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 attach a trailer, make sure that you have
correctly established the electrical connec-
tion. This can be accomplished by checking
the trailer lighting. Blind Spot Assist is then
deactivated. The indicator lamp lights up yel-
low in the exterior mirrors and the Blind
Spot Assist currently unavailable
See Owner's Manual message appears in
the multifunction display.
i You can deactivate the indicator lamps in
the exterior mirrors.
To do so, switch off Blind Spot Assist if:
R the key is in position 2 in 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 a camera at
the top of the windscreen. Lane Keeping
Assist detects lane markings on the road and
warns you before you leave your lane unin-
tentionally. Driving systems
199
Driving and parking Z

:
Lane Keeping Assist camera
If you select km on the on-board computer in
the Display unit Speed-/odometer func-
tion (Y page 220), Lane Keeping Assist is
active starting at a speed of 60 km/h
. If the
miles display unit is selected, the assistance
range begins at 40 mph.
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
Keeping

Assist can neither reduce the risk of
an accident 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 respon-
sible for the distance to the vehicle in front, for vehicle speed, for braking in good time,
and for staying in the lane.
Lane

Keeping Assist does not keep your vehi-
cle in its lane.
The system may be impaired or may not func-
tion if:
R there is poor visibility, e.g. due to insuffi-
cient 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, dam-
aged or covered, for instance by a sticker
in the vicinity of the camera
R no, or several, unclear lane markings are
present for one lane, e.g. in a construction
area
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 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
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.
Activating Lane Keeping Assist
X Activate Lane Keeping Assist using the on-
board computer; to do so, select Stand‐
ard or Adaptive(Y page 219).
If you drive at speeds above

60 km/h and
lane markings are detected, the lane mark-
ings in the assistance graphics display
(Y page 217) are shown in green. 200
Driving systems
Driving and parking

X
Press the 9 or : button to select the
number you want to dial.
X Press the 6
or a button to start dial-
ling.
or
X If you do not want to make a call: press
the ~ or % button.
Redialling The on-board computer saves the last names
or numbers dialled in the redial memory.
X
Press the =
or ; button on the steer-
ing wheel to select the Tel menu.
X Press the 6 button to switch to the
redial memory.
X Press the 9
or : button to select the
desired name or number.
X Press the 6
or a button to start dial-
ling.
or
X If you do not want to make a call: press
the ~ or % button. Assistance menu
Introduction In the
Assist.
menu, you have the following
options:
R Showing the assistance graphic
R Showing Speed Limit Assist and activat-
ing/deactivating its message function
R Activating/deactivating ESP ®
R Activating/deactivating the distance warn-
ing function R
Activating/deactivating ATTENTION
ASSIST
R Activating/deactivating Blind Spot Assist
R Activating/deactivating Lane Keeping
Assist
Showing the assistance graphic X
Press the =
or ; button on the steer-
ing wheel to select the Assist. menu.
X Press the 9 or : button to select
Assistance graphic.
X Press the a button.
The multifunction display shows the DIS-
TRONIC

PLUS distance display in the assis-
tance graphic (Y page 175).
The assistance graphic can display the status
of
and information from other driving systems
or driving safety systems.
The assistance graphic shows:
R the è symbol when the rear window
wiper ( Y page 118) is activated
R the é symbol when ATTENTION ASSIST
(Y page 195) is deactivated
R the lane markings as bright lines when Lane
Keeping Assist (Y page 199) is activated
R the Ä symbol when Speed Limit Assist
(Y page 196) is operational and the mes-
sage function is activated
The assistance graphic can also display
traffic signs that are detected and indicate
speed limits.
R the æ symbol when the distance warn-
ing function (Y page 62) is deactivated Menus and submenus
217On-board computer and displays Z

Further information on the distance warning
function (
Y page 62).
Activating/deactivating ATTENTION
ASSIST X
Press the = or ; button on the steer-
ing wheel to select the Assist. menu.
X Press the 9 or : button to select
ATTENTION ASSIST.
X Press the a button.
The current selection is displayed.
X To activate/deactivate: press the a
button again.
When ATTENTION ASSIST is deactivated,
the é

symbol appears in the multifunc-
tion display in the assistance graphics dis-
play.
For further information about ATTENTION
ASSIST, see ( Y page 195).
Activating/deactivating Blind Spot
Assist X
Press the =
or ; button on the steer-
ing wheel to select the Assist. menu.
X Press the 9 or : button to select
Blind Spot Assist.
X Press the a button.
The current selection is displayed.
X To activate/deactivate: press the a
button again.
For further information about Blind Spot
Assist, see (Y page 197).
When the Blind Spot Assist Sensors
deactivated message is shown, the radar
sensors are deactivated.
X Switch on the radar sensor system
(Y page 223). Activating/deactivating Lane Keeping
Assist X
Press the =
or ; button on the steer-
ing wheel to select the Assist. menu.
X Press the 9 or : button to select
Lane Keeping Assist.
X Press the a button.
The current selection is displayed.
X Press a to confirm.
X Press the : or 9 button to set Off,
Standard or Adaptive.
X Press the a button to save the setting.
When

Lane Keeping Assist is activated, the
multifunction display shows the lane mark-
ings as bright lines in the assistance
graphic.
For further information about Lane Keeping
Assist, see (Y page 199). Service menu
In the
Serv. menu, you have the following
options:
R Calling up display messages in the mes-
sage memory

(Y page 229)
R Restarting the tyre pressure loss warning
system (Y page 323)
R Calling up the service due date
(Y page 289) Menus and submenus
219
On-board computer and displays Z

Display messages Possible causes/consequences and
M SolutionsVehicles with Becker
®
MAP PILOT: if the Becker ®
MAP PILOT is
not connected, the radar sensor system is deactivated automati-
cally.
Blind Spot Assist is not available.
X Connect the Becker ®
MAP PILOT; see the separate operating
instructions. Lane Keeping
Assist currently
unavailable See
Owner's Manual Lane Keeping Assist is deactivated and temporarily inoperative.
Possible causes:
R
the windscreen is dirty in the camera's field of vision.
R visibility is impaired due to heavy rain, snow or fog.
R there are no lane markings for a longer period.
R the
lane markings are worn, dark or covered, e.g. by dirt or snow.
Once the causes listed above no longer apply, the display message
goes out.
Lane Keeping Assist is operational again.
If the display message does not disappear:
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away ( Y page 162).
X Clean the windscreen. Lane Keeping
Assist inoperative Lane Keeping Assist is faulty.
X
Visit a qualified specialist workshop. Blind Spot Assist
currently unavail‐
able See Owner's
Manual Blind Spot Assist is temporarily inoperative.
You

have established the electrical connection between the trailer
and your vehicle.
X Press a on the steering wheel to confirm the display mes-
sage.
Blind Spot Assist is deactivated while towing a trailer. Display messages
247
On-board computer and displays Z