2012 MERCEDES-BENZ B-CLASS warning light

monitored area. If you then switch on the
corresponding turn signal to change lanes,
you will also receive a visual and audible
collision warning.
For
this purpose, Blind Spot
Assist uses sensors in the rear bumper.
For Blind Spot Assist to assist you when
driving, the radar sensor system must be:
R activated(Y page 199)
R operational
Monitoring range of the sensors
In particular, the detection of obstacles can
be impaired if:
R dirt on the sensors or anything else
covering the sensors
R there is poor visibility, e.g. due to fog, heavy
rain or snow
R a narrow vehicle traveling in front, e.g. a
motorbike or bicycle
R the road has very wide lanes
R the road has narrow lanes
R you are not driving in the middle of the lane
R there are barriers or similar lane borders
Vehicles in the monitoring range are then not
indicated. Blind Spot Assist monitors the area up to
10 ft (
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
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.
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. For
example, the radar sensors must not be
covered by bicycle racks or overhanging
loads. Following a severe impact or in the
event of damage to the bumpers, have the
function of the radar sensors checked at a
qualified specialist workshop. Blind Spot
Assist may otherwise not work properly.
Indicator and warning display
Blind Spot Assist is not active at speeds below
approximately 20 mph (30 km/h). Vehicles in
the monitoring range are then not indicated. :
Yellow indicator lamp/red warning lamp
When Blind Spot Assist is activated, indicator
lamp : in the exterior mirrors lights up
yellow at speeds

of up to 20 mph (30 km/h).182
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At speeds above 20 mph (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
20 mph (30 km/h), warning lamp : on the
corresponding side lights up red. This warning
is always emitted 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).
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.
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, vehicles detected
are indicated by the flashing of red warning
lamp :. There are no further warning tones.
Switching on Blind Spot Assist
X Make sure that the radar sensor system
(Y page 199) and Blind Spot Assist
(Y page 195)
are

activated in the on-board
computer.
X Turn the SmartKey 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.
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 windshield. Lane Keeping Assist
detects lane markings on the road and warns you before you leave your lane
unintentionally.
:
Lane Keeping Assist camera
If you select km on the on-board computer in
the Display Unit Speed-/Odometer:
function ( Y page 196), 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 may not always clearly
recognize lane markings.
In this case, 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 stay in lane, in particular if
warned by Lane Keeping Assist. G
WARNING
The Lane Keeping Assist warning does not
return the vehicle to the original lane. There
is a risk of an accident.
You should always steer, brake or accelerate
yourself, in particular if warned by Lane
Keeping Assist.
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
the road, traffic and weather conditions. Lane Driving systems
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Driving and parking Z
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Keeping Assist is merely 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 your lane.
The Lane Keeping Assist does not keep the
vehicle in the 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 reflections (e.g. when the road
surface is wet)
R the windshield is dirty, fogged up, damaged
or covered, for instance by a sticker, in the
vicinity of the camera
R there are no, several or unclear lane
markings for a lane, e.g. in areas with road
construction work
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 strong shadows cast on the lane
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.
Switching on Lane Keeping Assist X
Switch on Active Lane Keeping Assist using
the on-board computer; to do so, select
Standard or Adaptive (Y page 195).
Symbol : appears in the multifunction
display.
If you drive at speeds above 40 mph
(60 km/h
) and lane markings are detected,
symbol : is highlighted. Lane Keeping
Assist is ready for use.
When 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 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, 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.
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.184
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Driving and parking
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Useful information
i This Operator's Manual describes all
models and all standard and optional
equipment of your vehicle available at the
time of publication of the Operator's
Manual. Country-specific differences are
possible. Please note
that your vehicle may
not be equipped with all features
described. This also applies to safety-
related systems and functions.
i Read the information on qualified
specialist workshops: ( Y page 24).Important safety notes
G
WARNING
If you operate information systems and
communication equipment integrated in the
vehicle while driving, you will be distracted
from traffic conditions. You could also lose
control of the vehicle. There is a risk of an
accident.
Only operate the equipment when the traffic
situation permits. If

you are not sure that this
is possible, park the vehicle paying attention
to traffic conditions and operate the
equipment when the vehicle is stationary. G
WARNING
If the instrument cluster has failed or
malfunctioned, you may not recognize
function restrictions in systems relevant to
safety. The operating safety of your vehicle
may be impaired. There is a risk of an
accident.
Drive on carefully. Have the vehicle checked
at a qualified specialist workshop
immediately.
You must observe the legal requirements for
the country in

which you are currently driving
when operating the on-board computer.
The on-board computer only shows messages
or warnings from certain systems in the multifunction display. You should therefore
make sure your vehicle is operating safely at
all times. Otherwise, a vehicle that is not
operating safely may cause an accident.
For an overview, see the instrument panel
illustration (
Y page 29). Displays and operation
Instrument cluster lighting
The lighting in the instrument cluster, in the
displays and the controls in the vehicle
interior can be

adjusted using the brightness
control knob.
The brightness control knob is located on the
bottom left of the instrument cluster
(Y page 29).
X Turn the brightness control knob clockwise
or counter-clockwise.
If the light switch is set to Ã, T or
L, the brightness is dependent upon
the brightness of the ambient light.
i The light sensor

in the instrument cluster
automatically controls the brightness of
the multifunction display.
In daylight, the displays in the instrument
cluster are not illuminated. Coolant temperature display
G
WARNING
Driving when your engine is overheated can
cause some fluids

which may have leaked into
the engine compartment to catch fire. You
could be seriously burned.
Steam from an overheated engine can cause
serious burns which can occur just by opening
the engine hood. Stay away from the engine
if you see or hear steam coming from it.
Stop the vehicle in a safe location away from
other traffic. Turn off the engine, get out of the
vehicle and do not stand near the vehicle until
the engine has cooled down. 186
Displays and operation
On-board computer and displays
ProCarManuals.com

A
Drive program (Y page 141)
B Transmission position ( Y page 141)
X To show menu bar ?: press the =
or ; button on the steering wheel.
Menu bar ? disappears after a few seconds.
Text field = shows the selected menu or
submenu as well as display messages.
i You can set the time using the audio
system or COMAND; see the separate
operating instructions.
The following messages may appear in the
multifunction display:
XjY Active Parking Assist (Y page 172)
CRUISE Cruise Control (Y page 157)
è Rear window wiper ( Y page 112)
_ Adaptive Highbeam Assist
(Y page 102)
À ATTENTION ASSIST (Y page 180)
à Lane Keeping Assist (Y page 183)
ë HOLD function ( Y page 167)
Ä Distance warning function
(Y page 233) Menus and submenus
Menu overview
Operating the on-board computer
(Y page 187).
Depending on the equipment installed in the
vehicle, you can call up the following menus:
R Trip menu (Y page 189)
R Navi menu (navigation instructions)
(Y page 191)
R Audio menu (Y page 192)
R Tel (telephone) menu ( Y page 193)
R DriveAssist (Assistance) menu
(Y page 194)
R Serv menu (Y page 196)
R Sett menu (Y page 196) The
Audio, Navi and
Tel
menus differ slightly
in vehicles with Audio 20 and in vehicles with
COMAND. The examples given in this
Operator's Manual apply to vehicles
equipped with COMAND. Trip menu
Standard display X
Press and hold the % button on the
steering wheel until the Trip menu with
trip odometer : and odometer ; is
shown.
Trip computer "From Start" or "From
Reset" Example: trip computer "From Start"
:
Distance
; Time
= Average speed
? Average fuel consumption
X Press the = or ; button on the
steering wheel to select the Trip menu.
X Press the 9 or : button to select
From Start or From Reset.
The values in the From Start submenu are
calculated from the start of a journey, while
the values in the From Reset submenu are
calculated from the last time the submenu
was reset ( Y page 190). Menus and submenus
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On-board computer and displays Z
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X
Start the engine.
X Press the = or ; button on the
steering wheel to select the DriveAssist
menu.
X Press the 9 or : button to select
ESP.
X Press the a button.
X To deactivate: press a again.
The å warning lamp in the instrument
cluster lights up.
X To activate: press a again.
The å warning lamp in the instrument
cluster goes out.
Switching the distance warning
function on and off X
Press the = or ; button on the
steering wheel to select the DriveAssist
menu.
X Press 9 or : to select Distance
Warning.
X Press the a button.
The current selection is displayed.
X To activate/deactivate: press the a
button again.
When the distance warning function is
activated, the multifunction display shows
the Ä symbol if the HOLD function is not
activated (Y page 167).
Vehicles with Active Parking Assist: if
PARKTRONIC is activated
and you are driving
at a speed under 22 mph (35 km/h), the j
Active Parking Assist symbol is shown instead
of the Ä symbol ( Y page 172).
Further information on the distance warning
function ( Y page 60). Activating/deactivating ATTENTION
ASSIST X
Press the = or ; button on the
steering wheel to select the DriveAssist
menu.
X Press 9 or : to select Attention
Asst.
X Press the a button.
The current selection is displayed.
X To activate/deactivate: press the a
button again.
When ATTENTION ASSIST (Y page 180) is
activated, the À symbol appears in the
multifunction display when

the ignition is on.
Activating/deactivating Blind Spot
Assist X
Press the = or ; button on the
steering wheel to select the DriveAssist
menu.
X Press 9 or :
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 181).
When the Blind Spot Assist: Sensors
Deactivated message is shown, the radar
sensors are deactivated.
X Switch on the radar sensor system
(Y page 199).
Activating/deactivating Lane Keeping
Assist X
Press the = or ; button on the
steering wheel to select the DriveAssist
menu.
X Press 9 or : on the steering wheel
to select Lane Keep. Asst. Menus and submenus
195
On-board computer and displays Z
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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.
If Lane Keeping Assist is activated
(Y page 183) and
the ignition is switched on,
the à symbol appears in the multifunction
display. Maintenance menu
In the
Serv menu, you have the following
options:
R Calling up display messages in message
memory ( Y page 200)
R Restarting the tire pressure loss warning
system (Y page 305)
R Calling up the service due date
(Y page 270) Settings menu
Introduction In the
Sett menu, you have the following
options:
R changing the instrument cluster settings
R changing the light settings
R changing the vehicle settings R
changing the convenience settings
R restoring the factory settings
Instrument cluster Selecting the unit of measurement for
distance
You can
determine

whether the multifunction
display shows some messages in miles or
kilometers.
X Press the = or ; button on the
steering wheel to select the Sett menu.
X Press the : or 9
button to select the
Inst. Cluster submenu.
X Press a to confirm.
X Press the :
or 9

button to select the
Display Unit Speed-/Odometer:
function.
You will see the selected setting km or
miles.
X Press the a button to save the setting.
The selected unit of measurement for
distance applies to:
R the digital speedometer in the Trip menu
R the odometer and the trip odometer
R the trip computer
R the current consumption and the range
R the navigation instructions in the Navi
menu
R cruise control
R DISTRONIC PLUS
R ASSYST PLUS service interval display
Switching the additional speedometer
on/off
Only vehicles
with

manual transmission have
this function.
X Press the = or ; button on the
steering wheel to select the Sett menu.
X Press the : or 9
button to select the
Inst. Cluster submenu.
X Press a to confirm.196
Menus and submenus
On-board computer and displays
ProCarManuals.com

Safety systems
Display messages Possible causes/consequences and
M Solutions!÷
Currently
Unavailable See
Operator's Manual ABS (Anti-lock Braking System), ESP
®
(Electronic Stability
Program), BAS (Brake Assist), the HOLD function and hill start
assist are temporarily unavailable.
COLLISION PREVENTION ASSIST may also have failed.
In addition, the ÷, å and ! warning lamps light up in
the instrument cluster.
ATTENTION ASSIST is deactivated.
Possible causes are:
R Self-diagnosis is not yet complete.
R The on-board voltage may be insufficient.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
The steerability and braking characteristics may be severely
affected. The braking distance in an emergency braking situation
can increase.
If ESP ®
is not
operational, ESP ®
is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
X Carefully drive a short distance on a suitable stretch of road,
making slight steering movements at a speed above 12 mph
(20 km/h).
If the display message disappears, the functions mentioned
above are available again.
If the display message continues to be displayed:
X Drive on carefully.
X Visit a qualified specialist workshop. !÷
Inoperative See
Operator's Manual ABS, ESP
®
, BAS, the HOLD function and hill start assist are
unavailable due to a malfunction.
COLLISION PREVENTION ASSIST may also have failed.
In addition, the J, ÷, å and ! warning lamps light
up in the instrument cluster.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example. Display messages
201On-board computer and displays Z
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