warning MERCEDES-BENZ B-CLASS 2012 Owners Manual

X
Open the tailgate.
X Lift the cargo compartment floor up
(Y page 246).
i Towing eye ; is located under tire
inflation compressor :.
Vehicles with a tire-change tool kit X
Open the tailgate.
X Lift the cargo compartment floor up
(Y page 246).
X Remove the tire-change tool kit.
The tire-change tool kit contains:
R Jack
R Lug wrench
R One pair of gloves
R Folding wheel chock Flat tire
Preparing the vehicle
Your vehicle may be equipped with:
R MOExtended tires (tires with run-flat
properties) ( Y page 281)
Vehicle preparation is not necessary on
vehicles with MOExtended tires.
R a TIREFIT kit (Y page 280)
Information on changing/mounting a wheel
(Y page 319).
X Stop the vehicle on solid, non-slippery and
level ground, as far away as possible from
traffic.
X Switch on the hazard warning lamps.
X Secure the vehicle against rolling away
(Y page 149).
X If possible, bring the front wheels into the
straight-ahead position.
X Switch off the engine.
X Remove the SmartKey from the ignition
lock. X
All occupants must get out of the vehicle.
Make sure that
they are not endangered as
they do so.
X Make sure that no one is near the danger
area while a wheel is being changed.
Anyone who is not directly assisting in the
wheel change should, for example, stand
behind the barrier.
X Get out of the vehicle. Pay attention to
traffic conditions when doing so.
X Close the driver's door.
i Vehicles equipped with

MOExtended tires
are not equipped with a TIREFIT kit at the
factory. It is therefore recommended that
you additionally equip your vehicle with a
TIREFIT kit if you mount tires that do not
feature run-flat properties, e.g. winter tires.
A TIREFIT kit can be obtained from a
qualified specialist workshop. MOExtended tires (tires with run-flat
properties)
General notes With MOExtended tires (tires with run flat
characteristics), you can continue to drive
your vehicle even if there is a total loss of
pressure in one or more tires. The affected
tire must
not

show any clearly visible damage.
You can recognize MOExtended tires by the
MOExtended marking which appears on the
sidewall of the tire. You will find this marking
next to the tire size designation, the load-
bearing capacity and the speed index
(Y page 313).
MOExtended tires may only be used in
conjunction with an active tire pressure loss
warning system.
If the pressure loss warning message
appears in the multifunction display:
R Observe the instructions in the display
messages ( Y page 219).
R Check the tire for damage.
R If driving on, observe the following notes. Flat tire
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The maximum driving distance is
approximately 50 miles (80 km) when the
vehicle is partially laden and approximately
18 miles (30 km) when the vehicle is fully
laden.
In addition to the vehicle load, the driving
distance possible depends upon:
R Speed
R Road condition
R Outside temperature
The driving
distance possible in run-flat mode
may be reduced by extreme driving
conditions/maneuvers, or it can be increased
through a moderate style of driving.
The maximum permissible distance which
can be driven in run-flat mode is counted from
the moment the tire pressure loss warning
appears in the multifunction display.
You must not exceed a maximum speed of
50 mph (80 km/h).
i When replacing one or all tires, make sure
that you use only tires:
R of the size specified for the vehicle and
R marked "MOExtended"
If a tire has gone flat and cannot be
replaced with a MOExtended tire, a
standard tire may be used as a temporary
measure. Make sure that you use the
proper size and type (summer or winter
tire).
i Vehicles equipped with MOExtended tires
are not equipped with a TIREFIT kit at the
factory. It is therefore recommended that
you additionally equip your vehicle with a
TIREFIT kit if you mount tires that do not
feature run-flat properties, e.g. winter tires.
A TIREFIT kit can be obtained from a
qualified specialist workshop.
Important safety notes G
WARNING
When driving in emergency mode, the driving
characteristics deteriorate, e.g. when cornering, accelerating quickly and when
braking. There is a risk of an accident.
Do not exceed the stated maximum speed.
Avoid abrupt
steering
and driving maneuvers,
and driving over obstacles (curbs, potholes,
off-road). This applies in particular to a laden
vehicle.
Stop driving in emergency mode if:
R you hear banging noises.
R the vehicle starts to shake.
R you see smoke and smell rubber.
R ESP ®
is intervening constantly.
R there are tears in the sidewalls of the tire.
After driving in emergency mode, have the
wheel rims checked at a qualified specialist
workshop with regard to their further use. The
defective tire must be replaced in every case. TIREFIT kit
Important safety notes G
WARNING
In the following situations, the tire sealant is
unable to provide sufficient breakdown
assistance, as it is unable to seal the tire
properly:
R there are cuts

or punctures in the tire larger
than those mentioned above.
R the wheel rim is damaged.
R you have driven at very low tire pressures
or on a flat tire.
There is a risk of an accident.
Do not drive any further. Contact a qualified
specialist workshop. G
WARNING
The tire sealant is harmful and causes
irritation. It must not come into contact with
your skin, eyes or clothing or be swallowed.
Do not inhale

TIREFIT fumes. Keep tire sealant
away from children. There is a risk of injury. 282
Flat tire
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X
Press on/off switch ? on the tire inflation
compressor to ON.
The tire inflation compressor is switched
on. The tire is inflated.
i First, tire sealant is pumped into the tire.
The pressure can briefly rise to
approximately 500 kPa (5 bar/73 psi).
Do not switch off the tire inflation
compressor during this phase.
X Let the tire inflation compressor run for a
maximum of ten minutes. The tire should
then have attained a pressure of at least
200 kPa (2.0 bar/29 psi).
! Do not operate the tire inflation
compressor for longer than ten minutes at
a time without a break. It may otherwise
overheat.
The tire inflation compressor can be
operated again once it has cooled down.
If a pressure

of 200 kPa (2.0 bar/29 psi) has
been attained after a maximum of after ten
minutes, see ( Y page 284).
If a pressure of 200 kPa (2.0 bar/29 psi) has
not been attained after a maximum of ten
minutes, see ( Y page 284).
i If tire sealant leaks out, allow it to dry. It
can then be removed like a layer of film.
If your clothes are soiled with tire sealant,
have them cleaned with perchloroethylene
at a dry cleaner as soon as possible.
Tire pressure not reached If a pressure of 200 kPa (
2.0 bar
/29 psi) has
not been achieved after ten minutes:
X Switch off the tire inflation compressor.
X Unscrew the filler hose from the valve of
the faulty tire.
X Very slowly drive forwards or reverse
approximately 30 ft (10 m).
X Pump up the tire again.
After a maximum of ten minutes, the tire
pressure

must be
at least 200 kPa (2.0 bar/
29 psi). G
WARNING
If the required tire pressure is not reached
after the specified time, the tire is too badly
damaged. The tire sealant cannot repair the
tire in this

instance. Damaged tires and a tire
pressure that is too low can significantly
impair the vehicle's braking and driving
characteristics. There is a risk of accident.
Do not continue driving. Contact a qualified
specialist workshop.
Tire pressure reached G
WARNING
A tire temporarily sealed with tire sealant
impairs the driving characteristics and is not
suitable for higher speeds. There is a risk of
accident.
You should therefore adapt your driving style
accordingly and drive

carefully. Do not exceed
the specified maximum speed with a tire that
has been repaired using tire sealant.
! After use, excess tire sealant may run out
of the filler hose. This could cause stains.
Therefore, place the filler hose in the plastic
bag that contained the TIREFIT kit. H
Environmental note
Have the used tire sealant bottle disposed of
professionally, e.g. at a qualified specialist
workshop.
If a tire

pressure of 200 kPa (2.0 bar/29 psi)
has been achieved after ten minutes:
X Switch off the tire inflation compressor.
X Unscrew the filler hose from the valve of
the faulty tire.
X Stow the tire sealant bottle and the tire
inflation compressor.
X Pull away immediately.
The maximum speed for a tire sealed with tire
sealant is 50 mph (

80 km/h). The upper part
of the TIREFIT sticker must be affixed to the
instrument cluster in the driver's field of
vision. 284
Flat tire
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X
Stop after driving for approximately ten
minutes and check the tire pressure with
the tire inflation compressor.
The tire pressure must now be at least
130 kPa (1.3 bar/19 psi). G
WARNING
If the required tire pressure is not reached
after driving for a short period, the tire is too
badly damaged. The
tire sealant cannot repair
the tire in this instance. Damaged tires and a
tire pressure that is too low can significantly
impair the vehicle's braking and driving
characteristics. There is a risk of accident.
Do not continue driving. Contact a qualified
specialist workshop.
X Correct the tire pressure if it is still at least
130 kPa (1.3 bar/19 psi) (for the values,
see the Tire and Loading Information
placard on the driver's side B-pillar or tire
pressure table on the fuel filler flap).
X To increase the tire pressure: switch on
the tire inflation compressor. X
To reduce the tire pressure: depress
pressure release button : next to
pressure gauge ;. X
To remove the tire sealant bottle from the
tire inflation compressor, press together
the locking tabs on the yellow cap.
X Pull the tire sealant bottle out of the tire
inflation compressor.
The filler hose

remains attached to the tire
sealant bottle.
X Stow the tire sealant bottle and the tire
inflation compressor.
X Drive to the nearest qualified specialist
workshop and have

the tire changed there.
X Have the tire sealant bottle and the filler
hose replaced as soon as possible at a
qualified specialist workshop.
X Have the tire sealant bottle replaced every
four years at a qualified specialist
workshop. Battery (vehicle)
Important safety notes
Special tools and expert knowledge are
required when working on the battery, e.g.
removal and installing. You should therefore
have all work

involving the battery carried out
at a qualified specialist workshop. G
WARNING
Work carried out incorrectly on the battery
can, for example, lead to a short circuit and
damage your vehicle's

electronic system. This
can disrupt driving safety systems such as
ABS (anti-lock braking system) or ESP ®
(Electronic Stability Program). Battery (vehicle)
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R
If ABS malfunctions, the wheels can lock
during braking. This limits the steerability
of the vehicle
when braking and the braking
distance may increase. There is a risk of
accident.
R If ESP ®
malfunctions, the vehicle will not be
stabilized if it starts to skid or a wheel starts
to spin. There is a risk of accident.
You should therefore have all work involving
the battery carried out at a qualified specialist
workshop. G
WARNING
Electrostatic build-up can lead to the creation
of sparks, which could ignite the highly
explosive gases of

a battery. There is a risk of
an explosion.
Before handling the battery, touch the vehicle
body to remove any existing electrostatic
build-up.
The highly flammable gas mixture forms when
charging the battery as well as when jump-
starting.
Always make sure that neither you nor the
battery is electrostatically charged. There is
a build-up of electrostatic charge, e.g.:
R by wearing clothing made from synthetic
fibers
R due to friction between clothing and seats
R if you push or pull the battery across the
carpet or other synthetic materials
R if you wipe the battery with a cloth. G
WARNING
During the charging process, a battery
produces hydrogen gas. If a short circuit
occurs or sparks are created, the hydrogen
gas can ignite.

There is a risk of an explosion.
R Make sure that the positive terminal of a
connected battery does not come into
contact with vehicle parts.
R Never place metal objects or tools on a
battery. R
It is important that you observe the
described order of the battery terminals
when connecting and disconnecting a
battery.
R When jump-starting, make sure that the
battery poles with identical polarity are
connected.
R It is particularly important to observe the
described order when connecting and
disconnecting the jumper cables.
R Never connect or disconnect the battery
terminals while the engine is running. G
WARNING
Battery acid is caustic. There is a risk of injury.
Avoid contact with

the skin, eyes or clothing.
Do not inhale any battery gases. Do not lean
over the battery. Keep children away from
batteries. Wash battery acid immediately with
water and seek medical attention. H
Environmental note Batteries contain dangerous
substances. It is against the
law to dispose of them with
the household rubbish. They
must be
collected

separately
and recycled to protect the
environment. Dispose of batteries in an
environmentally friendly
manner. Take discharged
batteries to a qualified
specialist workshop or a
special collection point for
used batteries.
! Have the battery checked regularly at a
qualified specialist workshop.
Observe the service intervals in the
Maintenance Booklet or

contact a qualified
specialist workshop for more information.
! You should have all work involving the
battery carried out at a qualified specialist
workshop. In the exceptional case that it is 286
Battery (vehicle)
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necessary for you to disconnect the battery
yourself, make sure that:
R
you switch off
the engine and remove the
SmartKey. Check that all the indicator
lamps in the instrument cluster are off.
Otherwise, electronic components, such
as the alternator, may be damaged.
R you first remove the negative terminal
clamp and then the positive terminal
clamp. Never swap the terminal clamps.
Otherwise, the vehicle's electronic
system may be damaged.
R on vehicles with automatic transmission,
the transmission is locked in position P
after disconnecting the battery. The
vehicle is secured against rolling away.
You can then no longer move the vehicle.
The battery and the cover of the positive
terminal clamp must be installed securely
during operation.
Comply with safety precautions and take
protective measures when handling
batteries. WARNING
Fire, open flames and smoking are
prohibited when handling the
battery. Avoid creating sparks.
Battery acid is caustic. Avoid
contact with the skin, eyes or
clothing.
Wear suitable protective clothing,
in particular gloves, an apron and
a face mask.
Immediately rinse acid splashes
off with clean water. Consult a
doctor if necessary.
Wear eye protection. Keep children away.
Observe this Operator's Manual.
For safety reasons, Mercedes-Benz
recommends that you only use batteries
which have been tested and approved for
your vehicle by Mercedes-Benz. These
batteries provide increased impact
protection to prevent

vehicle occupants from
suffering acid burns should the battery be
damaged in the event of an accident.
In order for the battery to achieve the
maximum possible service life, it must always
be sufficiently charged.
Like other batteries, the vehicle battery may
discharge over time if you do not use the
vehicle. In this case, have the battery
disconnected at a qualified specialist
workshop. You can also charge the battery
with a charger recommended by Mercedes-
Benz. Contact a qualified specialist workshop
for further information.
Have the battery charge level checked more
frequently if you use the vehicle mainly for
short trips or if you leave it standing idle for
a lengthy period. Consult a qualified specialist
workshop if you wish to leave your vehicle
parked for a long period of time.
Only replace a battery with a battery that has
been recommended by Mercedes-Benz.
i Remove the SmartKey if you park the
vehicle and do not require any electrical
consumers. The vehicle will then use very
little energy, thus conserving battery
power. Battery (vehicle)
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i
If the power supply has been interrupted,
e.g. if you reconnect the battery, you will
have to:
R set the clock (audio system/COMAND,
see the
separate operating instructions).
R reset the function for folding the exterior
mirrors in/out automatically, by folding
the mirrors out once ( Y page 93).Charging the battery
G
WARNING
During charging and jump-starting, explosive
gases can escape

from the battery. There is a
risk of an explosion.
Particularly avoid fire, open flames, creating
sparks and smoking. Ensure there is sufficient
ventilation while charging and jump-starting.
Do not lean over a battery. G
WARNING
Battery acid is caustic. There is a risk of injury.
Avoid contact with

the skin, eyes or clothing.
Do not inhale any battery gases. Do not lean
over the battery. Keep children away from
batteries. Wash battery acid immediately with
water and seek medical attention. G
WARNING
A discharged battery can freeze at
temperatures below freezing point. When
jump-starting the vehicle or charging the
battery, gases can escape from the battery.
There is a risk of an explosion.
Allow the frozen battery to thaw out before
charging it or jump-starting.
! Only use battery chargers with a
maximum charging voltage of 14.8 V.
! Only charge the battery using the jump-
starting connection point.
The jump-starting connection point is in the
engine compartment (Y

page 289). X
Open the hood (Y page 266).
X Connect the battery charger to the positive
terminal and ground point in the same
order as when connecting the donor
battery in the jump-starting procedure
(Y page 289).
If, at low temperatures, the indicator lamps/
warning lamps in the instrument cluster do
not light up, it is highly likely that the
discharged battery has frozen. In this case
you may neither jump-start the vehicle nor
charge the battery. The service life of a
thawed-out battery may be shorter. The
starting characteristics can be impaired,
particularly at low temperatures. Have the
thawed-out battery checked at a qualified
specialist workshop.
Only charge the installed battery with a
battery charger which has been tested and
approved by Mercedes-Benz. An accessory
battery charge unit specially adapted for
Mercedes-Benz vehicles and tested and
approved by Mercedes-Benz is available. It
permits the charging of the battery in its
installed position. Contact an authorized
Mercedes-Benz Center for further
information and availability.

Read the battery
charger's operating instructions before
charging the battery. 288
Battery (vehicle)
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Jump-starting
For the jump-starting
procedure, use only the jump-starting connection point, consisting of a
positive terminal and an earth point, in the engine compartment. G
WARNING
Battery acid is caustic. There is a risk of injury.
Avoid contact with the skin, eyes or clothing. Do not inhale any battery gases. Do not lean over
the battery. Keep children away from batteries. Wash battery acid immediately with water and
seek medical attention. G
WARNING
During charging and jump-starting, explosive gases can escape from the battery. There is a risk
of an explosion.
Particularly avoid fire, open flames, creating sparks and smoking. Ensure there is sufficient
ventilation while charging and jump-starting. Do not lean over a battery. G
WARNING
During the charging process, a battery produces hydrogen gas. If a short circuit occurs or sparks
are created, the hydrogen gas can ignite. There is a risk of an explosion.
R Make sure that the positive terminal of a connected battery does not come into contact with
vehicle parts.
R Never place metal objects or tools on a battery.
R It is important

that you observe the described order of the battery terminals when connecting
and disconnecting a battery.
R When jump-starting, make sure that the battery poles with identical polarity are connected.
R It is particularly important to observe the described order when connecting and disconnecting
the jumper cables.
R Never connect or disconnect the battery terminals while the engine is running. G
WARNING
A discharged battery can freeze at temperatures below freezing point. When jump-starting the
vehicle or charging

the battery, gases can escape from the battery. There is a risk of an explosion.
Allow the frozen battery to thaw out before charging it or jump-starting. G
WARNING
Non-combusted fuel can collect in the exhaust system and ignite. There is a risk of fire. Avoid
repeated and lengthy starting attempts.
! Avoid repeated and

lengthy starting attempts. Otherwise, the catalytic converter could be
damaged by the non-combusted fuel.
If, at low temperatures, the indicator lamps/warning lamps in the instrument cluster do not
light up, it is highly likely that the discharged battery has frozen. In this case you may neither
jump-start the vehicle nor charge the battery. The service life of a thawed-out battery may be Jump-starting
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Position number
B identifies the charged battery of the other vehicle or an equivalent jump-
starting device.
X Press together cover : of positive clamp ; and slide it back.
X Connect positive terminal ; on your vehicle to positive terminal = of donor battery B
using the jumper cable, beginning with your own battery.
X Start the engine of the donor vehicle and run it at idling speed.
X Connect negative terminal ? of
donor
battery B to ground point A of your vehicle using
the jumper cable, connecting the jumper cable to donor battery B first.
X Start the engine.
X Before disconnecting the jumper cables, let the engine run for several minutes.
X First, remove the jumper cables from earth point A and negative terminal ?, then from
positive clamp ; and positive terminal =. Begin each time at the contacts on your own
vehicle first.
X Close cover : of positive terminal ; after removing the jumper cables.
X Have the battery checked at a qualified specialist workshop.
i Jump-starting is not considered to be a normal operating condition.
i Jumper cables and further information regarding jump-starting can be obtained at any
qualified specialist workshop. Towing and tow-starting
Important safety notes
G
WARNING
Functions relevant to safety are restricted or
no longer available if:
R the engine is not running.
R the brake system or the power steering is
malfunctioning.
R there is a

malfunction in the voltage supply
or the vehicle's electrical system.
If your vehicle is being towed, much more
force may be necessary to steer or brake.
There is a risk of an accident.
In such cases, use a tow bar. Before towing,
make sure that the steering moves freely. G
WARNING
If the weight of the vehicle to be towed or tow-
started is greater than the permissible gross
weight of your vehicle:
R the towing eye could detach itself
R the vehicle/trailer combination could
rollover.
There is a risk of an accident.
When towing or tow-starting another vehicle,
its weight should not be greater than the
permissible gross weight of your vehicle.
Information on your vehicle's gross vehicle
weight rating can be found on the vehicle
identification plate ( Y page 328). G
WARNING
The vehicle is braked if the HOLD function is
activated. Therefore, deactivate HOLD if the
vehicle is to be towed. Towing and tow-starting
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Towing the vehicle with the front axle
raised
! The ignition must be switched off if the
vehicle is being towed with the front axle
raised. Otherwise, ESP®

may intervene and
damage the brake system.
X Turn the SmartKey to position 2 in the
ignition lock.
X When the vehicle is stationary, depress the
brake pedal and keep it depressed.
X Shift the automatic transmission to
position P.
X Release the brake pedal.
X Release the electric parking brake.
X Deactivate automatic locking
(Y page 198).
X Switch on the hazard warning lamps
(Y page 101).
X Turn the SmartKey to position 0 in the
ignition lock and

leave the SmartKey in the
ignition lock.
When towing your vehicle with the front axle
raised, it is important that you observe the
safety instructions ( Y page 291).Towing a vehicle with both axles on
the ground
G
WARNING
The power assistance for the steering and the
brake force booster do not work when the
engine is not running. You will then need
much more effort to brake and steer the
vehicle. Adapt your style of driving
accordingly.
i In order to signal a change of direction
when towing with

the hazard warning lamps
switched on, use the combination switch as
usual. In this case, only the turn signals for
the desired direction flash. When you reset
the combination switch, the hazard
warning lamps start flashing again. The automatic transmission automatically
shifts
to position P

when you open the driver's
or front-passenger door or when you remove
the SmartKey from the ignition lock. In order
to ensure that the automatic transmission
stays in position N when towing the vehicle,
you must observe the following points:
X Make sure that the vehicle is stationary.
X Turn the SmartKey to position 2 in the
ignition lock.
X Depress and hold the brake pedal.
X Shift the automatic transmission to
position N.
X Leave the SmartKey in position 2 in the
ignition lock.
X Release the brake pedal.
X Release the electric parking brake.
X Switch on the hazard warning lamps
(Y page 101).
It is important that you observe the safety
instructions when towing away your vehicle
(Y page 291). Transporting the vehicle
! Only lash the

vehicle down by the wheels
or wheel rims, not by parts of the vehicle
such as axle or steering components.
Otherwise, the vehicle could be damaged.
X Turn the SmartKey to position 2 in the
ignition lock.
X Shift the transmission to position N.
As soon as the vehicle is loaded:
X Prevent the vehicle from rolling away by
applying the electric parking brake.
X Shift the transmission to position P.
X Turn the SmartKey to position 0 in the
ignition lock and remove it.
X Secure the vehicle.
The towing eye can be used to pull the vehicle
onto a trailer or transporter for transporting
purposes. Towing and tow-starting
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