MERCEDES-BENZ B-CLASS 2012 Owners Manual

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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shorter. The starting characteristics can be impaired, particularly at low temperatures. Have
the thawed-out battery checked at a qualified specialist workshop.
Do not
start
the vehicle using a rapid charging device. If your vehicle's battery is discharged,
the engine can be jump-started from another vehicle or from a second battery using jumper
cables. Observe the following points:
R The battery is not accessible in all vehicles. If the other vehicle's battery is not accessible,
jump-start the vehicle using a second battery or a jump-starting device.
R You may only jump-start the vehicle when the engine and exhaust system are cold.
R Do not start the engine if the battery is frozen. Let the battery thaw first.
R Jump-starting may only be performed from batteries with a nominal voltage of 12 V.
R Only use jumper cables which have a sufficient cross-section and insulated terminal clamps.
R If the battery is fully discharged, leave the battery that is being used to jump-start connected
for a few minutes before attempting to start. This charges the battery slightly.
R Make sure that the two vehicles do not touch.
Make sure that:
R the jumper cables are not damaged.
R bare parts of the terminal clamp do not come into contact with other metal parts while the
jumper cables are connected to the battery.
R the jumper cables cannot come into contact with parts which can move when the engine
is running, such as the V-belt pulley or the fan.
X Secure the vehicle 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 Switch off all electrical consumers (e.g. radio, blower, etc.).
X Open the hood (Y page 266).290
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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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!
Only secure the
tow rope or tow bar at the
towing eyes. Otherwise, the vehicle could
be damaged.
! Do not use the towing eyes for recovery
purposes as this could damage the vehicle.
If in doubt, recover the vehicle with a crane.
! When towing, pull away slowly and
smoothly. If the tractive power is too high,
the vehicles could be damaged.
! The vehicle can be towed a maximum of
30 miles (50km). The towing speed of
30 mph (50km/h) must not be exceeded.
If the vehicle has to be towed more than
30 miles (50km), the front axle must be
raised or the entire vehicle raised and
transported.
! Do not tow with sling-type equipment.
This could damage the vehicle.
! Vehicles with automatic transmission
must not be started by tow-starting. This
could otherwise damage the transmission.
It is better to have the vehicle transported
than to have it towed.
When towing a vehicle, the transmission must
be in position N.
The battery must be connected and charged.
Otherwise, you:
R cannot turn the SmartKey to position 2 in
the ignition lock
R cannot shift the transmission to position
N.
i Deactivate the automatic locking feature
(Y page 198). You could otherwise be
locked out when pushing or towing the
vehicle. Installing/removing the towing eye
Installing the towing eye X
Remove the towing eye from the stowage
space.
The towing eye is beneath the cargo
compartment floor with

the vehicle tool kit
(Y page 280).
Vehicles with the TIREFIT kit: the towing
eye is beneath the tire inflation
compressor.
X Press the mark on cover : inwards in the
direction of the arrow.
X Take cover : off the opening.
X Screw in and tighten the towing eye
clockwise to the stop.
Removing the towing eye X
Unscrew and remove the towing eye.
X Attach cover : to the bumper and press
until it engages.
X Place the towing eye in the stowage well
beneath the cargo compartment floor
(Y page 280) in the cargo compartment.
X Vehicles with the TIREFIT kit: put back the
tire inflation compressor.292
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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Tow-starting (emergency engine
starting)
! Vehicles with automatic transmission
must not be tow-started. You could
otherwise damage the automatic
transmission.
When tow-starting, it is important that you
observe the safety
instructions (Y page 291).Fuses
Important safety notes
G
WARNING
If you manipulate or bridge a faulty fuse or if
you replace it with a fuse with a higher
amperage, the electric cables could be
overloaded. This could result in a fire. There
is a risk of an accident and injury.
Always replace faulty

fuses with the specified
new fuses having the correct amperage.
! Only use fuses that have been approved
for Mercedes-Benz vehicles and which
have the correct fuse rating for the system
concerned. Only use fuses marked with an
"S". Otherwise, components or systems
could be damaged.
The fuses in your vehicle serve to close down
faulty circuits. If a fuse blows, all the
components on the circuit and their functions
stop operating.
Blown fuses must be replaced with fuses of
the same rating, which you can recognize by
the color and value. The fuse ratings are listed
in the fuse allocation chart.
If a newly inserted fuse also blows, have the
cause traced and rectified at a qualified
specialist workshop, e.g. an authorized
Mercedes-Benz Center. Before changing a fuse
X Secure the vehicle against rolling away
(Y page 149).
X Switch off all electrical consumers.
X Turn the SmartKey to position 0 in the
ignition lock and remove it (Y page 135).
All indicator lamps

in the instrument cluster
must be off.
The fuses are located in various fuse boxes:
R Fuse box in

the engine compartment on the
left-hand side of the vehicle, when viewed
in the direction of travel
R Fuse box in the front-passenger footwell
The fuse allocation chart is on the fuse box in
the front-passenger footwell ( Y page 295). Fuse box in the engine compartment
G
WARNING
When the hood is open and the windshield
wipers are set in motion, you can be injured
by the wiper linkage. There is a risk of injury.
Always switch off the windshield wipers and
the ignition before opening the hood.
! Make sure that

no moisture can enter the
fuse box when the cover is open.
! When closing the cover, make sure that it
is lying correctly on the fuse box. Moisture
seeping in or dirt could otherwise impair
the operation of the fuses. 294
Fuses
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X
Open the hood.
X Use a dry cloth to remove any moisture
from the fuse box.
X To open: open clamps ;.
X Fold up cover : in the direction of the
arrow and remove it. X
To close: check whether the seal is seated
correctly in cover :.
X Insert cover :
at the back into openings
= on the fuse box.
X Fold down cover :.
X Hook clamps ; into the fuse box and
close.
X Close the hood. Fuse box in the front-passenger
footwell
X
To open: remove the floormat from the
front-passenger side.
X Fold out perforated floor covering :
in the
direction of the arrow. X
To release cover =, press retaining
clamp ;.
X Fold out cover = in the direction of the
arrow to the catch.
X Remove cover = forwards.
i Fuse allocation
chart ?

is located on the
lower right-hand side of cover =.
X To close: insert cover = on the left-hand
side of the fuse box into the retainer.
Cover = engages in the retainers.
X Fold down cover = until clamps ; lock
audibly.
X Fold back perforated floor covering :. Fuses
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Useful information ............................
298
Important safety notes ....................298
Operation ........................................... 298
Winter operation ............................... 300
Tire pressure ..................................... 301
Loading the vehicle ..........................306
Maximum load rating .......................310
Uniform Tire Quality Grading
Standards .......................................... 311
Tire labeling ....................................... 312
Definition of terms for tires and
loading ............................................... 316
Changing a wheel ............................. 319
Wheel and tire combinations ...........323
Emergency spare wheel ...................325 297Wheels and tires
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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 wheels and tires of the wrong size are used,
the wheel brakes or suspension components
may be damaged. There is a risk of an
accident.
Always replace wheels and tires with those
that fulfill the specifications of the original
part.
When replacing wheels,

make sure to use the
correct:
R designation
R model
When replacing tires, make sure to use the
correct:
R designation
R manufacturer
R model G
WARNING
A flat tire severely impairs the driving,
steering and braking characteristics of the
vehicle. There is a risk of accident.
Tires without run-flat characteristics:
R do not drive with a flat tire.
R immediately replace the flat tire with your
emergency spare wheel or spare wheel, or
consult a qualified specialist workshop. Tires with run-flat characteristics:
R
pay attention to the information and
warning notices on

MOExtended tires (tires
with run-flat characteristics).
Accessories that are not approved for your
vehicle by Mercedes-Benz or are not being
used correctly can impair the operating
safety.
Before purchasing and using non-approved
accessories, visit a qualified specialist
workshop and inquire about:
R suitability
R legal stipulations
R factory recommendations
Information on dimensions and types of
wheels and tires for your vehicle can be found
(Y page 323).
Information on air pressure for the tires on
your vehicle can be found:
R on the vehicle's Tire and Loading
Information placard on the B-pillar
R on the tire pressure label on the fuel filler
flap
R under "Tire pressure"
i Further information on wheels and tires
can be obtained at any qualified specialist
workshop. Operation
Information on driving
R If the vehicle is heavily loaded, check the
tire pressures and correct them if
necessary.
R While driving, pay attention to vibrations,
noises and unusual handling
characteristics, e.g. pulling to one side.
This may indicate that the wheels or tires
are damaged. If you suspect that a tire is
defective, reduce your speed immediately.
Stop the vehicle as soon as possible to
check the wheels and tires for damage.
Hidden tire damage could also be causing298
Operation
Wheels and tires
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