2012 MERCEDES-BENZ B-CLASS engine

Top view
The sensors must be free from dirt, ice or
slush. They can otherwise not function
correctly. Clean
the
sensors regularly, taking
care not to scratch or damage them
(Y page 275).
Front sensors Center Approx. 40in (approx.
100cm)
Corners Approx. 24in (approx.
60cm)
Rear sensors
Center Approx. 48 in (approx.
120 cm)
Corners Approx. 32in (approx.
80cm)
Minimum distance
Center Approx. 8in (approx. 20cm)
Corners Approx. 8in (approx. 20cm)
If there is an obstacle within this range, the
relevant warning displays light up and a
warning tone sounds. If the distance falls
below the minimum, the distance may no
longer be shown.
Warning displays
The warning displays show the distance
between the sensors and the obstacle. The
warning display for the front area is located on the dashboard above the center air vents.
The warning display for the rear area is
located on the headliner in the rear
compartment.
Warning display for the front area
:
Segments on the left-hand side of the
vehicle
; Segments on the right-hand side of the
vehicle
= Segments showing operational readiness
The warning display for each side of the
vehicle is divided

into five yellow and two red
segments. PARKTRONIC is operational if
yellow segments showing operational
readiness = light up.
The selected transmission position and the
direction in which the vehicle is rolling
determine which warning display is active
when the engine is running. Transmission
position Warning display
D
Front area activated
R, N or the vehicle
is rolling
backwards Rear and front areas
activated
P
No areas activated
One or more segments light up as the vehicle
approaches an obstacle, depending on the
vehicle's distance from the obstacle.170
Driving systems
Driving and parking
ProCarManuals.com

The Park Assist Active Select R
Observe Surroundings

message appears in
the multifunction display.
X Further transmission shifts may be
necessary.
As soon as the parking procedure is
complete, the Park Assist Finished
message appears in the multifunction
display.
Active Parking Assist is then deactivated.
PARKTRONIC is still available.
X Maneuver if necessary.
X Always observe the warning messages
displayed by PARKTRONIC (
Y page 170).
Parking tips:
R The way your vehicle is positioned in the
parking space after parking is dependent
on various factors. These include the
position and shape of the vehicles parked
in

front and
behind it and the conditions of
the location. It may be the case that Active
Parking Assist guides you too far into a
parking space, or not far enough into it. In
some cases, it may also lead you across or
onto the curb. If necessary, you should
cancel the parking procedure with Active
Parking Assist.
R You can also engage forward gear
prematurely. The vehicle redirects and
does not drive as far into the parking space.
Should a gear be changed too early, the
parking procedure will be canceled. A
sensible parking position can no longer be
achieved from this position.
Exiting a parking space In order that Active Parking Assist can
support you
when

you exit the parking space:
R the border of the parking space must not
be too low.
R the border of the parking space must not
be too wide. The system maneuvers the
vehicle into a position at a maximum of 45° to the starting position in the parking
space.
R a maneuvering distance of at least 24 in
(0.60 m) must be available.
Active Parking Assist

can only assist you with
exiting a parking space if you have parked the
vehicle using Active Parking Assist.
X Start the engine.
X Switch on the turn signal on the side facing
the street.
X Shift the transmission to position D or R.
The Start Park Assist? Yes: OK No:
% message appears

in the multifunction
display.
X To cancel the procedure: press the
% button on the multifunction steering
wheel or pull away.
or
X To exit a parking space using Active
Parking Assist: press the a button on
the multifunction steering wheel.
The Park Assist Active Accelerate
and Brake Observe Surroundings
message appears in the multifunction
display.
X Let go of the multifunction steering wheel.
X Reverse the vehicle or drive forwards, being
ready to brake at all times. Do not exceed
a maximum speed of approximately
6 mph (10 km/h) when exiting a parking
space. Otherwise

Active Parking Assist will
be canceled.
X Stop when PARKTRONIC sounds the
continuous warning tone, if not before.
X Shift the transmission to position D or R
as
required while the vehicle is stationary.
Active Parking Assist immediately steers in
the other direction. The Park Assist
Active Accelerate and Brake
Observe Surroundings message appears
in the multifunction display.
i You will achieve the best results by
waiting for the steering procedure to
complete before pulling away. Driving systems
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Driving and parking Z
ProCarManuals.com

Warning and display messages in the
multifunction display
X
Activate ATTENTION ASSIST using the on-
board computer ( Y page 195).
Symbol : appears in the multifunction
display.
If ATTENTION ASSIST is active, it will not
warn you until at least 20 minutes after
your journey has begun. You then hear an
intermittent warning tone twice and the
Attention Assist: Drowsiness
Detected message appears in the
multifunction display.
X If necessary, take a break.
X Press the
a button 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, you will be warned again
after 15 minutes at the earliest. The
precondition for this is that
ATTENTION ASSIST still detects typical
indicators of fatigue or increasing lapses in
concentration.
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 181) and Lane Keeping
Assist (Y page 183).
Blind Spot Assist Important safety notes
G
WARNING
Blind Spot Assist does not react to:
R vehicles overtaken too closely on the side,
placing them in the blind spot area
R vehicles approaching and driving by with a
speed difference of more than 6.8 mph
(11 km/h )
As a result, Blind Spot Assist may not give
warnings in

such situations. There is a risk of
an accident.
Always observe the traffic conditions
carefully, and maintain a safe lateral distance.
Blind Spot Assist is only an aid. It may fail to
detect some vehicles and is no substitute for
attentive driving.
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. Removing, tampering
with, or altering 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.
General notes
Blind Spot Assist uses a radar sensor system
to monitor the areas on both sides of your
vehicle. It supports you from a speed of
approximately 20 mph (30 km/h). A warning
display in the exterior mirrors draws your
attention to vehicles detected in the Driving systems
181
Driving and parking Z
ProCarManuals.com

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 display message
is shown if the coolant
temperature is too high.
If the coolant temperature is over
248 ‡(120 †), do not continue driving. The
engine will otherwise be damaged.
The coolant temperature gage is in the
instrument cluster on the right-hand side.
Under normal operating conditions and with
the specified coolant level, the coolant
temperature may rise to 248 ‡ (120 †). Tachometer
! Do not drive in the overrevving range, as
this could damage the engine.
The red band

in the tachometer indicates the
engine's overrevving range.
The fuel supply is interrupted to protect the
engine when the red band is reached. Outside temperature display
You should pay special attention to road
conditions when temperatures are around
freezing point.
The outside temperature display is in the
multifunction display.
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.
R Cruise control activated ( Y page 157):
The segments light up from the stored
speed to the maximum speed.
R DISTRONIC PLUS activated (Y page 159):
One or two segments in the set speed
range light up.
R 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 :
Multifunction display
; Switches on the Voice Control System;
see the separate operating instructions
= Right control panel
? Left control panel
A Back button
X To activate the on-board computer: 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. Displays and operation
187
On-board computer and displays Z
ProCarManuals.com

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
ProCarManuals.com

Activating/deactivating surround
lighting and exterior lighting delayed
switch-off
If you have activated the
Locator
Lighting: function
and
the light switch is set
to Ã, the following functions are activated
when it is dark:
R surround lighting: the exterior lighting
remains lit for 40 seconds after unlocking
with the SmartKey. If you start the engine,
the surround lighting is switched off and
automatic headlamp mode is activated
(Y page 99).
R exterior lighting delayed switch-off: the
exterior lighting remains lit for
60 seconds after the engine is switched off.
If you close all the doors and the trunk lid,
the exterior lighting goes off after
15 seconds.
X Press the = or ; button on the
steering wheel to select the Sett. menu.
X Press the :
or 9
button to select the
Lights submenu.
X Press a to confirm.
X Press the : or 9
button to select the
Locator Lighting function.
You will see the selected setting: Enabled
or Disabled.
X Press the a button to save the setting.
Deactivating delayed switch-off of the
exterior lighting temporarily:
X Before leaving the vehicle, turn the
SmartKey to position 0

in the ignition lock.
X Turn the SmartKey to position 2 in the
ignition lock.
The exterior lighting delayed switch-off is
deactivated.
Delayed switch-off of the exterior lighting is
reactivated the next time you start the
engine.
i Depending on your vehicle's equipment,
when the surround lighting and delayed
switch-off exterior lighting are on, the
following light up: R
Parking lamps
R Front fog lamps
R Low-beam headlamps
R Daytime running lamps
R Side marker lamps
R Surround lighting in the exterior mirrors
Activating/deactivating the interior
lighting delayed switch-off
If you activate the Interior Lighting
Delay function, the interior lighting remains
on for 20seconds after you remove the
SmartKey from the ignition lock.
X Press the = or ; button on the
steering wheel to select the Sett. menu.
X Press the : or 9
button to select the
Lights submenu.
X Press a to confirm.
X Press the :
or 9

button to select the
Interior Lighting Delay function.
You will see the selected setting: Enabled
or Disabled.
X Press the a button to save the setting.
Vehicle Activating/deactivating the automatic
door locking mechanism
X
Press the = or ; button on the
steering wheel to select the Sett menu.
X Press the :
or 9
button to select the
Vehicle submenu.
X Press a to confirm.
X Press the :
or 9

button to select the
Automatic Door Lock function.
You will see the selected setting: Enabled
or Disabled.
X Press the a button to save the setting.
If you select the Automatic Door Lock
function, the
vehicle

is centrally locked above
a speed of around 9 mph (15 km/h).
i For further information on the automatic
locking feature, see ( Y page 74).198
Menus and submenus
On-board computer and displays
ProCarManuals.com

Display messages Possible causes/consequences and
M SolutionsThe yellow
! warning lamp lights up. If you manually apply or
release the electric parking brake, the red F (USA
only)/! (Canada only) indicator lamp flashes.
The electric parking brake is malfunctioning. It is not possible to
apply the electric parking brake manually.
X Shift the transmission to P.
X Visit a qualified specialist workshop. F(USA
only)!(Canada
only)
Parking Brake
Inoperative The yellow
! warning lamp lights up. The red F (USA
only)/! (Canada only) indicator lamp flashes for about ten
seconds after the electric parking brake has been applied or
released. It then goes out or remains lit.
The electric parking brake is malfunctioning, e.g. because of
overvoltage or undervoltage.
X Remove the cause for the overvoltage or undervoltage, e.g. by
charging the battery or restarting the engine.
X Engage or release the electric parking brake.
If it remains impossible to apply or release the electric parking
brake:
X Switch off the ignition and turn it back on.
X Engage or release the electric parking brake.
If the electric parking brake still cannot be released:
X Consult a qualified specialist workshop. The display message is only shown while the vehicle is in motion.
The yellow
! warning lamp lights up and the red F (USA
only)/ ! (Canada only) indicator lamp flashes.
It is not possible to apply the electric parking brake manually.
X Shift the transmission to P.
X Visit a qualified specialist workshop. F(USA
only)!(Canada
only)
Turn On the
Ignition to
Release the
Parking Brake The red
F (USA
only)/ ! (Canada only) indicator lamp lights
up.
You attempted to release the electric parking brake while the
ignition was switched off.
X Turn the SmartKey to position 1 in the ignition lock.206
Display messages
On-board computer and displays
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