key battery MERCEDES-BENZ A CLASS 2012 Owner's Manual

Flammable material such as leaves, grass or
twigs
may ignite if they come into contact with
hot parts of the exhaust system for extended
periods. There is a risk of fire.
When the auxiliary heating is switched on,
make sure that no flammable material can
come into contact with hot vehicle compo-
nents.
! Operating the auxiliary heating/ventila-
tion draws on the vehicle battery. After you
have heated or ventilated the vehicle a
maximum of two times, drive for a longer
distance.
i Switch the auxiliary heating on regularly
once a month for about ten minutes.
Comfort Switching belt adjustment on/off
X
Press the =
or ; button on the steer-
ing wheel to select the Settings menu.
X Press the :
or 9 button to select the
Convenience submenu.
X Press a to confirm.
X Press the :
or 9 button to select the
Belt adjustment function.
If the Belt adjustment function is activa-
ted, the vehicle seat belt is shown in orange
in the multifunction display.
X Press the a button to save the setting.
For further information on belt adjustment,
see ( Y page 47).
Switching the fold in mirrors when lock-
ing function on/off
This

function is only available on vehicles with
a memory function (Y page 101).
When you activate the Auto. fold-in mir‐
rors function, the exterior mirrors are folded
in when the vehicle is locked.
When you unlock the vehicle and then open a
door, the exterior mirrors fold out again.
If you have switched on the Auto. fold-in
mirrors function and you fold in the exterior mirrors using the button on the door
(Y page 99), they will not fold out automati-
cally. The exterior mirrors can then only be
folded out using the button on the door.
X
Press the =
or ; button on the steer-
ing wheel to select the Settings menu.
X Press the :
or 9 button to select the
Convenience submenu.
X Press a to confirm.
X Press the :
or 9 button to select the
Auto. fold-in mirrors function.
If the Auto. fold-in mirrors function is
activated, the vehicle's exterior mirror is
displayed in orange in the multifunction
display.
X Press the a button to save the setting.
Resetting to factory settings X
Press the =
or ; button on the steer-
ing wheel to select the Settings menu.
X Press the :
or 9 button to select the
Factory setting submenu.
X Press a to confirm.
The Reset all settings? message
appears.
X Press the : or 9 button to select
No or Yes.
X Press the a
button to confirm the selec-
tion.
If you have selected Yes , the multifunction
display shows a confirmation message.
For safety reasons, not all functions are reset:
the Limit speed (winter tyres): func-
tion

in permanent SPEEDTRONIC can only be
set in the VEHICLE submenu. If you want to
reset the Daytime driving lights: in the
Light submenu, you must turn the key in the
ignition lock to position 1. Menus and submenus
225
On-board computer and displays Z

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 ! indicator lamp
flashes.
The electric parking brake is malfunctioning. It is not possible to
apply the electric parking brake manually.
X Vehicles with manual transmission: engage first gear.
X Vehicles with automatic transmission: shift the transmission
to P.
X Visit a qualified specialist workshop. !
Parking

brake inop‐
erative The yellow
! warning lamp lights up. The red ! 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 over-
voltage or undervoltage.
X Rectify the cause of the overvoltage or undervoltage, e.g. by
charging the battery or restarting the engine.
X Apply 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 Apply 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

red ! indicator lamp flashes and the yellow ! warning
lamp is lit.
It is not possible to apply the electric parking brake manually.
X Vehicles with manual transmission: engage first gear.
X Vehicles with automatic transmission:
shift the transmission
to P.
X Visit a qualified specialist workshop. !
Turn on the igni‐
tion to release
the parking brake The red
! indicator lamp lights up.
You
attempted to release the electric parking brake while the igni-
tion was switched off.
X Turn the key to position 1 in the ignition lock. Display messages
235
On-board computer and displays Z

Rear-compartment ashtray
X
To open: pull cover = out by its top edge.
X To remove: pull insert ; by recess : in
the direction of arrow ? until it audibly
releases.
X Lift insert ; up and out.
X To fit the insert: fit insert ; from above
into the holder and press down into the
holder until it engages. Cigarette lighter
G
WARNING
You can burn yourself if you touch the hot
heating
element or the socket of the cigarette
lighter.
In addition, flammable materials can ignite if:
R the hot cigarette lighter falls
R a child holds the hot cigarette lighter to
objects, for example
There is a risk of fire and injury.
Always hold the cigarette lighter by the knob.
Always make sure that the cigarette lighter is
out of reach of children. Never leave children
unattended in the vehicle.
Your attention must always be focused on the
traffic conditions. Only use the cigarette
lighter when road and traffic conditions per-
mit. Example: vehicles with a stowage compartment
cover
X
Turn the key to position 2 in the ignition
lock (Y page 143).
X To open: push the lower section of
cover :.
The stowage compartment opens.
X Press in cigarette lighter ;.
Cigarette lighter ; will pop out automati-
cally when the heating element is red-hot. 12 V sockets
Points to observe before use X
Turn the key to position 1 in the ignition
lock (Y page 143).
The sockets can be used for accessories with
a maximum draw of
180 W (15 A). Accesso-
ries include such items as lamps or chargers
for mobile phones.
If you use the sockets for long periods when
the engine is switched off, the battery may
discharge.
i An emergency cut-off ensures that the on-
board voltage does not drop too low. If the
on-board voltage is too low, the power to
the sockets is automatically cut. This
ensures that there is sufficient power to
start the engine. 278
Features
Stowing and features

sive 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 is formed
when charging the battery or jump-starting
the vehicle.
Always make sure that neither you nor the
battery is electrostatically charged. Electro-
static charge is caused, for example, by:
R wearing synthetic clothing
R the friction of clothing on the seat
R pulling or sliding the battery over carpets
or other synthetic materials
R rubbing the battery with a cloth G
WARNING
During the charging process, a battery produ-
ces 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 con-
tact with vehicle parts.
R Never place metal objects or tools on a bat-
tery.
R It is important that you observe the descri-
bed 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 dis-
connecting the jump leads.
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 pollutants.
It

is illegal to dispose of them
with the household rubbish.
They must be collected sep-
arately and disposed of in an
environmentally responsible
recycling system. Dispose of batteries in an
environmentally responsible
manner. Take discharged
batteries to a qualified spe-
cialist workshop or to a col-
lection

point for used batter-
ies.
! Have the battery checked regularly at a
qualified specialist workshop.
Observe

the service intervals in the Service
Booklet or contact a qualified specialist
workshop for more information.
! Always have work on the battery carried
out at a qualified specialist workshop.
Should it, in exceptional circumstances, be
absolutely necessary to disconnect the bat-
tery yourself, please observe the following:
R switch off the engine and remove the
key. Check that all the indicator lamps in
the instrument cluster are off. Otherwise,
you may damage electronic components
such as the alternator, for example.
R first, disconnect the negative terminal
clamp, followed by the positive terminal
clamp. Never swap the terminal clamps.
The vehicle electronics may otherwise be
damaged.
R on vehicles with automatic transmission,
the transmission is locked in position P
after disconnecting the battery. The vehi-
cle is secured against rolling away. You
can then no longer move the vehicle. Battery (vehicle)
305
Breakdown assistance Z

The battery and the cover of the positive
terminal
clamp must be fitted securely dur-
ing operation.
Comply with safety precautions and take pro-
tective measures when handling batteries. WARNING
Fire, naked flames and smoking
are prohibited when handling the
battery. Avoid creating sparks.
Battery acid is caustic. Avoid con-
tact

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 doc-
tor if necessary. Wear eye protection.
Keep children away.
Observe this Owner's Manual.
For safety reasons, Mercedes-Benz recom-
mends
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 vehi-
cle occupants from suffering acid burns
should the battery be damaged in the event
of an accident.
In order for the battery to achieve the maxi-
mum 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 such cases, have the battery dis-
connected at a qualified specialist workshop. You can also charge the battery with a
charger recommended by Mercedes-Benz.
For

more information, please contact a quali-
fied specialist workshop.
Have the battery charge checked more fre-
quently 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 up for a long period of time.
i When you park the vehicle, remove the
key if you do not require any electrical con-
sumers. The vehicle will then use very little
energy, thus conserving battery power.
i If the power supply has been interrupted,
e.g. if the battery was discharged, you will
have to:
R set the clock (audio system/COMAND
Online, 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 99). 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, naked 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. 306
Battery (vehicle)
Breakdown assistance

characteristics may be impaired, especially at low temperatures. Have the thawed battery
checked at a qualified specialist workshop.
Do
not use a rapid charging device to start the vehicle. If your vehicle's battery is discharged,
the engine can be jump-started from another vehicle or from a second battery using jump
leads. 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 Vehicles with a petrol engine: 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 jump leads that 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 empty battery a little.
R Make sure that the two vehicles do not touch.
Make sure that:
R the jump leads are not damaged.
R bare parts of the terminal clamp do not come into contact with other metal parts while the
jump leads are connected to the battery.
R the jump leads 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 Manual transmission: shift into neutral.
X Automatic transmission: shift the transmission to position P.
X Turn the key to position 0 in the ignition lock and remove it.
X Switch off all electrical consumers (e.g. radio, blower, etc.).
X Open the bonnet (Y page 285). Jump-starting
309
Breakdown assistance Z

!
Only secure the tow rope or towing bar to
the towing eyes. The vehicle may otherwise
be damaged.
! Observe the following points when towing
with a tow rope:
R secure the tow rope on the same side on
both vehicles.
R make sure that the tow rope is not longer
than legally permitted. Mark the tow rope
in the middle, e.g. with a white cloth
(30 x 30 cm). This makes other road
users aware that a vehicle is being
towed.
R only secure the tow rope to the towing
eye.
R observe the brake lamps of the towing
vehicle while driving. Always maintain a
distance so that the tow rope does not
sag.
R do not use steel cables or chains to tow
your vehicle. You could otherwise dam-
age the vehicle.
! Do not use the towing eyes for recovery
purposes as this could damage the vehicle.
If in doubt, recover the vehicle with a crane.
! Pull away smoothly when towing away or
tow-starting a vehicle. If the tractive power
is too high, the vehicles could be damaged.
! You may tow the vehicle for a maximum
of 50km. A towing speed of 50 km/h must
not be exceeded.
For towing distances over 50 km, the front
axle or the entire vehicle must be raised
and transported.
! Vehicles with automatic transmission
must not be tow-started. The transmission
may otherwise be damaged.
Observe the legal requirements for the rele-
vant countries when towing and tow-starting.
It is better to have the vehicle transported
than to have it towed. Vehicles with automatic transmission:
when
towing a vehicle, the transmission must
be in position N.
The battery must be connected and charged.
Otherwise, you:
R cannot turn the key in the ignition lock to
position 2
R vehicles with automatic transmission:
cannot shift the transmission to position N
i Deactivate the automatic locking feature
(Y page 223). You could otherwise be
locked out when pushing or towing the
vehicle.
Deactivate tow-away protection
(Y page 70) before the vehicle is towed. Fitting/removing the towing eye
Fitting the towing eye X
Remove the towing eye from the stowage
space.
The towing eye is located with the vehicle
tool kit under the luggage compartment
floor ( Y page 299). Towing and tow-starting
311
Breakdown assistance Z

Vehicles with automatic transmission:
the
automatic transmission automatically shifts
to position P when you open the driver's or
front-passenger door or when you remove the
key from the ignition lock. In order to ensure
that the automatic transmission stays in posi-
tion N when towing the vehicle, you must
observe the following points:
X Make sure that the vehicle is stationary.
X Turn the key to position 2 in the ignition
lock.
X Depress and hold the brake pedal.
X Shift the automatic transmission to posi-
tion N.
Vehicles with manual transmission:
X Turn the key to position 2 in the ignition
lock.
X Depress and hold the brake pedal.
X Engage neutral.
Vehicles with manual or automatic trans-
mission:
X Leave the key 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 108).
It is important that you observe the safety
instructions when towing away your vehicle
(Y page 310). 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. Oth-
erwise, the vehicle could be damaged. X
Vehicles with manual transmission:
shift to neutral.
X Vehicles with automatic transmission:
turn the key to position 2 in the ignition
lock.
X Move 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 Vehicles with manual transmission:
engage first or reverse gear.
X Vehicles with automatic transmission:
shift the transmission to position P.
X Turn the key to position 0 in the ignition
lock and remove it.
X Secure the vehicle.
The towing eyes or trailer tow hitch can be
used
to pull the vehicle onto a trailer or trans-
porter if you wish to transport it. Notes for 4MATIC vehicles
! Vehicles

with 4MATIC must not be towed
with the front or rear axle raised; otherwise,
the transmission may be damaged.
Vehicles with 4MATIC may only be either
towed away with both axles on the ground or
be loaded up and transported.
If the vehicle has transmission damage or
damage to the front or rear axle, have it trans-
ported on a transporter or trailer.
In the event of damage to the electrical
system
If the battery is defective, the automatic
transmission will be locked in position P. To
shift the automatic transmission to position
N, you must provide power to the vehicle's
electrical system in the same way as when
jump-starting (Y page 308).
Have the vehicle transported on a transporter
or trailer. Towing and tow-starting
313
Breakdown assistance Z

Tow-starting (emergency engine
starting)
! Do not tow-start vehicles with automatic
transmission.
You could otherwise damage
the automatic transmission.
Before tow-starting, the following conditions
must be fulfilled:
R the battery is connected.
R the engine has cooled down.
R the exhaust system has cooled down.
X Switch on the hazard warning lamps
(Y page 108).
X Fit the towing eye (Y page 311).
X Secure the rigid towing bar or the towing
rope.
X Depress and hold the brake pedal.
X Turn the key to position 2 in the ignition
lock.
X Depress the clutch pedal and keep it
depressed.
X Engage neutral.
X Release the brake pedal.
X Tow-start the vehicle.
X Engage second gear.
X Release the clutch pedal slowly without
depressing the accelerator pedal.
The engine is started.
X Depress the clutch pedal and shift to neu-
tral.
X Stop at a suitable place.
X Secure the vehicle by applying the electric
parking brake.
X Remove the rigid towing bar or towing rope.
X Remove the towing eye (Y page 312).
X Switch off the hazard warning lamps.
When tow-starting, it is important that you
observe the safety instructions ( Y page 310)
and the legal requirements for the relevant
countries. Electrical fuses
Important safety notes
G
WARNING
If you manipulate, bridge or replace a faulty
fuse with a fuse of a higher amperage, the
electric

cables could be overloaded. This may
result in a fire. There is a risk of an accident
and injury.
Always replace faulty fuses with specified new
fuses of 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". Components or systems could other-
wise be damaged.
The fuses in your vehicle serve to disconnect
faulty circuits. If a fuse blows, all the compo-
nents on the circuit and their functions will
fail.
Blown fuses must be replaced with fuses of
the same rating, which you can recognise by
the colour and fuse rating. The fuse ratings
are listed in the fuse allocation chart.
If the newly inserted fuse also blows, have the
cause traced and rectified at a qualified spe-
cialist workshop, e.g. a Mercedes-Benz
Service Centre. Before replacing a fuse
X Secure the vehicle against rolling away
(Y page 162).
X Switch off all electrical consumers.
X Turn the key to position 0 in the ignition
lock and remove it (Y page 143). All indi-
cator

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 footwell314
Electrical fuses
Breakdown assistance