2012 MERCEDES-BENZ B-CLASS air condition

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).Overview of climate control systems
Important safety notes
Observe the settings recommended on the
following pages. The windows could
otherwise fog up.
To prevent the windows from fogging up:
R switch off climate control only briefly
R switch on air-recirculation mode only
briefly
R switch on the cooling with air
dehumidification function
R switch on the defrost windshield function
briefly, if required
The automatic climate control regulates the
temperature and the humidity of the vehicle
interior and filters out undesirable
substances from the air.
Automatic climate control/dual-zone
automatic climate control is only operational
when the engine is running. Optimum
operation is only achieved with the side
windows and panorama

roof with power tilt/
sliding panel closed.
The residual heat function can only be
activated or deactivated with the ignition
switched off (Y page 129).
i Ventilate the vehicle for a brief period
during warm weather, e.g. using the
convenience opening feature ( Y page 78).This will speed up the cooling process and
the desired vehicle interior temperature
will be reached more quickly.
i The integrated filter can filter out most
particles of dust,

and completely filters out
pollen. A clogged filter reduces the amount
of air supplied to the vehicle interior. For
this reason, you should always observe the
interval for replacing the filter, which is
specified in the Maintenance Booklet. As it
depends on environmental conditions, e.g.
heavy air pollution, the interval may be
shorter than stated in the Maintenance
Booklet.
i It is possible that the dehumidification
function of the climate control system may
be activated automatically an hour after the
SmartKey has been removed. The vehicle
is then ventilated for 30 minutes. 118
Overview of climate control systems
Climate control
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?
To activate/deactivate air-recirculation mode ( Y page 129)
A To set the airflow ( Y page 126)
B To switch cooling with air dehumidification on/off ( Y page 123)
C To switch the rear window defroster on/off (Y page 128) Notes on using automatic climate
control
Automatic climate control The following contains notes and
recommendations on optimum use of the
automatic climate control.
R
Switch on the air-conditioning system by
turning control knob A clockwise to the
desired position (except position 0).
R Set the temperature to 72 ‡ (22 †).
R Recommendation for preventing
fogged up windows with low outside
temperatures
or rain: switch ¯ on for
the air distribution and switch P and
O off if possible (Y page 126).
In air-recirculation mode, switch d off
(Y page 129).
Set airflow control A to a setting between
3 and 6(Y page 126).
R Recommendation for rapid cooling or
heating of the vehicle interior: briefly set
airflow control A to a setting between 3
and 6(Y page 126).
R Recommendation for a constant
vehicle interior temperature: set airflow
control A to a setting between 1 and
3(Y page 126).
R Recommendation for air distribution in
the winter: set O and
¯(Y page 126).
Recommendation for air distribution in
the summer: set P or P and
¯(Y page 126).
R Only use the "windshield defrosting"
function briefly until the windshield is clear
again. R
Only use
air-recirculation

mode briefly, e.g.
if there are unpleasant outside odors or
when in a tunnel. The windows could
otherwise fog up, since no fresh air is drawn
into the vehicle in air-recirculation mode.
R If you change the settings of the climate
control system, the climate status display
appears for three seconds at the bottom of
the screen in the COMAND display. See
also the separate COMAND operating
instructions 4
. You will see the current
settings of the various climate control
functions.
ECO start/stop function During automatic engine switch-off, the ECO
start/stop function only operates at a
reduced capacity. If you require the full
climate control
output,

you can switch off the
ECO start/stop function by pressing the ECO
button ( Y page 138).
4 Only for vehicles with "COMAND Multimedia System" optional equipment120
Overview of climate control systemsClimate control
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The stop/start function is automatically
activated each
time
you start the engine with
the SmartKey.
If the ECO start/stop function has been
manually deactivated ( Y page 138) or a
malfunction has caused the system to be
deactivated, the ¤ symbol is not
displayed.
Automatic engine switch-off General notes
The ECO start/stop function is operational
and the ¤ symbol is displayed in the
multifunction display, if:
R
the indicator lamp in the ECO button is lit
green.
R the outside temperature is within the
comfort range.
R the engine is at normal operating
temperature.
R the set temperature

for the vehicle interior
has been reached.
R the battery is sufficiently charged.
R the system detects that the windshield is
not fogged up when the air-conditioning
system is switched on.
R the hood is closed.
R the driver's door is closed and the driver's
seat belt is fastened.
If conditions for automatic engine switch-off
have not been fulfilled, the ¤ symbol will
not be shown.
i All of the vehicle's systems remain active
when the engine has been stopped
automatically.
i The engine can be switched off
automatically a maximum of four times
(first stop and three subsequent stops) in
succession. Automatic engine switch-off is
possible again once the ECO symbol
appears in the multifunction display. Vehicles with automatic transmission
If the vehicle is braked to a standstill in
D or
N, the ECO start/stop function switches off
the engine automatically.
i The HOLD function

can be activated if the
engine has been switched off
automatically. It is then not necessary to
continue applying the brakes during the
automatic stop phase. When you depress
the accelerator pedal, the engine starts
automatically and the braking effect of the
HOLD function is deactivated.
Automatic engine start General notes
The engine starts automatically if:
R
you switch off

the ECO start/stop function
by pressing the ECO button.
R you engage reverse gear R.
R the vehicle starts to roll.
R the brake system requires this.
R the temperature in the vehicle interior
deviates from the set range.
R the system detects moisture on the
windshield when the air-conditioning
system is switched on.
R the condition of charge of the battery is too
low.
R the driver's seat belt is removed or the
driver's door is opened.
Vehicles with automatic transmission
The engine is started automatically if you:
R release the brake pedal when HOLD is not
activated and the transmission is in
position D or N.
R depress the accelerator pedal.
R move the transmission out of position P.
i Shifting the transmission to position P
does not start the engine.
i If you shift the transmission from R to D,
the ECO start/stop function is available Driving
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i
On long journeys
at a constant speed, e.g.
on the highway, only the bar for Constant
will change.
i The ECO display summaries the driving
characteristics from the start of the journey
to its completion. For this reason, the bars
change dynamically at the beginning of the
journey. On longer journeys, there are
fewer changes. For more dynamic changes,
carry out a manual reset.
Further information on the ECO display
(Y page 190). Brakes
Important safety notes G
WARNING
If you shift down on a slippery road surface in
an attempt to increase the engine's braking
effect, the drive wheels could lose their grip.
There is an increased danger of skidding and
accidents.
Do not shift down for additional engine
braking on a slippery road surface.
Downhill gradients !
On long and steep gradients, you must
reduce the load

on the brakes by shifting to
a lower gear in good time. This allows you
to take advantage of the engine's braking
effect. For this, you need to have selected
manual drive program M. This helps you to
avoid overheating the brakes and wearing
them out excessively.
When you take advantage of the engine's
braking effect, a drive wheel may not turn
for some time, e.g. on a slippery road
surface. This could cause damage to the
drive train. This type of damage is not
covered by the Mercedes-Benz warranty.
i Briefly depressing the accelerator pedal
on downhill gradients while the manual
drive program M is temporarily activated:
the automatic transmission may switch to the last active automatic drive program
E
or S. The automatic

transmission may shift
to a higher gear. This can reduce the
engine's braking effect.
Heavy and light loads G
WARNING
If you rest your foot on the brake pedal while
driving, the braking

system can overheat. This
increases the stopping distance and can even
cause the braking system to fail. There is a
risk of an accident.
Never use the brake pedal as a footrest. Never
depress the brake pedal and the accelerator
pedal at the same time.
! Depressing the brake pedal constantly
results in excessive and premature wear to
the brake pads.
If the brakes have been subjected to a heavy
load, do not stop the vehicle immediately.
Drive on for a short while. This allows the
airflow to cool the brakes more quickly.
Wet roads If you have driven for a long time in heavy rain
without braking, there may be a delayed
reaction from
the

brakes when braking for the
first time. This may also occur after the
vehicle has been washed or driven through
deep water.
You have to depress the brake pedal more
firmly. Maintain a greater distance from the
vehicle in front.
After driving on a wet road or having the
vehicle washed, brake firmly while paying
attention to the traffic conditions. This will
warm up the brake discs, thereby drying them
more quickly and protecting them against
corrosion.
Limited braking performance on salt-
treated roads If you drive on salted roads, a layer of salt
residue may form on the brake discs and154
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Front wheel
Rear wheel
X
Bring the vehicle and wheels into a suitable
position so that you can attach test gauge
A.
X Secure the vehicle against rolling away
(Y page 149).
X Move the selector lever to position P.
X Switch off the engine.
X Place test gauge A between the wheel's
spokes on brake pad/lining =. X
Hold test gauge A vertically on brake
disc : and slide measuring pin ; onto
brake disc :.
X Check which color field ? the arrow on
measuring pin ; is pointing to.
Green: the brake pad/lining thickness is
sufficient.
Red: the brake pad/lining thickness is not
sufficient. Have the brake pads/lining
checked at
a
qualified specialist workshop.
i To avoid an inaccurate measurement:
R make sure you position the wheels
suitably
R do not
put

the measuring pin on a recess
in the brake disc Driving on wet roads
Hydroplaning If water has accumulated to a certain depth
on the road surface, there is a danger of
hydroplaning occurring, even if:
R
you drive at low speeds.
R the tires have adequate tread depth.
For this reason, in the event of heavy rain or
in conditions in which hydroplaning may
occur, you must drive in the following
manner:
R lower your speed.
R avoid ruts.
R brake carefully.
Driving on flooded roads !
Do not drive through flooded areas.
Check the depth

of any water before driving
through it. Drive slowly through standing
water. Otherwise, water may enter the
vehicle interior or the engine compartment.
This can damage the electronic
components in the engine or the automatic
transmission. Water can also be drawn in
by the engine's air suction nozzles and this
can cause engine damage. 156
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Winter driving
General notes G
WARNING
If you shift down on a slippery road surface in
an attempt to increase the engine's braking
effect, the drive wheels could lose their grip.
There is an increased danger of skidding and
accidents.
Do not shift down for additional engine
braking on a slippery road surface. G
DANGER
If the exhaust pipe is blocked or adequate
ventilation is not possible, poisonous gases
such as carbon
monoxide (CO) may enter the
vehicle. This is the case, e.g. if the vehicle
becomes trapped in snow. There is a risk of
fatal injury.
If you leave the engine or the auxiliary heating
running, make sure the exhaust pipe and area
around the vehicle are clear of snow. To
ensure an adequate supply of fresh air, open
a window on the side of the vehicle that is not
facing into the wind.
Have your vehicle winterproofed at a qualified
specialist workshop at the onset of winter.
Observe the notes in the "Winter operation"
section ( Y page 300).
Driving with summer tires Observe the notes in the "Winter operation"
section (
Y page 300).
Slippery road surfaces G
WARNING
If you shift down on a slippery road surface in
an attempt to increase the engine's braking
effect, the drive wheels could lose their grip.
There is an increased danger of skidding and
accidents.
Do not shift down for additional engine
braking on a slippery road surface. If the vehicle threatens to skid or cannot be
stopped when moving at low speed:
X
Shift the transmission to position N.
Drive particularly carefully on slippery road
surfaces. Avoid sudden

acceleration, steering
and braking maneuvers. Do not use the cruise
control or DISTRONIC PLUS.
The outside temperature indicator is not
designed to serve as an ice-warning device
and is therefore unsuitable for that purpose.
Changes in the outside temperature are
displayed after a short delay.
Indicated temperatures just above the
freezing point do not guarantee that the road
surface is free of ice. The road may still be icy,
especially in wooded areas or on bridges. You
should pay special attention to road
conditions when temperatures are around
freezing point.
i For more information on driving with
snow chains, see ( Y page 301). Driving systems
Cruise control
Important safety notes If you fail to adapt your driving style, cruise
control can neither reduce the risk of an
accident nor override the laws of physics.
Cruise control cannot take into account the
road, traffic and weather conditions. Cruise
control 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 your lane.
Do not use cruise control:
R in road and traffic conditions which do not
allow you to maintain a constant speed e.g.
in heavy traffic or on winding roads
R on slippery road surfaces. Braking or
accelerating could cause the drive wheels Driving systems
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In such cases, DISTRONIC PLUS may:
R
give an unnecessary warning and then
brake the vehicle
R neither give a warning nor intervene
R accelerate unexpectedly
There is a risk of an accident.
Continue to drive carefully and be ready to
brake, in particular when warned to do so by
DISTRONIC PLUS. G
WARNING
DISTRONIC PLUS brakes your vehicle with up
to 40% of the maximum braking force. If this
braking force is
insufficient, DISTRONIC PLUS
warns you visually and audibly. There is a risk
of an accident.
In such cases, apply the brakes yourself and
try to take evasive action.
! If DISTRONIC PLUS or the HOLD function
is activated, the vehicle brakes
automatically in certain situations. To
prevent damage to the vehicle, deactivate
DISTRONIC PLUS and the HOLD function in
the following or other similar situations:
R when towing the vehicle
R in the car wash
If you fail to adapt your driving style,
DISTRONIC PLUS can neither reduce the risk
of accident nor override the laws of physics.
DISTRONIC PLUS cannot take into account
the road, traffic and weather conditions.
DISTRONIC PLUS 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 your lane.
Do not use DISTRONIC PLUS:
R in road and traffic conditions which do not
allow you to maintain a constant speed e.g.
in heavy traffic or on winding roads
R on slippery road surfaces. Braking or
accelerating could cause the drive wheels to lose traction and the vehicle could then
skid
R when there is

poor visibility, e.g. due to fog,
heavy rain or snow
DISTRONIC PLUS may not detect narrow
vehicles driving in front, e.g. motorcycles, or
vehicles driving on a different line.
In particular, the detection of obstacles can
be impaired if:
R dirt on the sensors or anything else
covering the sensors
R snow or heavy rain
R interference by other radar sources
R strong radar reflections, for example, in
parking garages
If DISTRONIC PLUS no longer detects a
vehicle in front, DISTRONIC PLUS may
unexpectedly accelerate the vehicle to the
stored speed.
This speed may:
R be too high if you are driving in a filter lane
or an exit lane
R be so high when driving in the right-hand
lane that you overtake vehicles in the left-
hand lane
R be so high when driving in the left-hand lane
that you overtake vehicles in the right-hand
lane
If there is a change of drivers, advise the new
driver of the speed stored.
General notes DISTRONIC PLUS regulates the speed and
automatically helps you maintain the
distance to the vehicle detected in front.
DISTRONIC PLUS brakes automatically so
that the set speed is not exceeded.
On long and steep downhill gradients,
especially if the vehicle is laden, you must
select a low gear in good time. For this, you
will need to have selected manual drive
program
M(Y page 154).

By doing so, you will
make use of the braking effect of the engine.
This relieves the load on the brake system and 160
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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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