2012 MERCEDES-BENZ A CLASS key battery

Problems with the engine
Problem Possible causes/consequences and
M SolutionsThe engine does not
start. The HOLD function or DISTRONIC PLUS is activated.
X
Deactivate the HOLD function (Y page 179) or DISTRONIC
PLUS (Y page 173).
X Try to start the engine again. The engine does not
start.
The starter motor
can be heard. R
There is a malfunction in the engine electronics.
R There is a malfunction in the fuel supply.
X Turn the key back to position 0 in the ignition lock before
attempting to start the engine again.
X Try to start the engine again (Y page 143). Avoid excessively
long

and frequent attempts to start the engine, as this will drain
the battery.
If the engine does not start after several attempts:
X Consult a qualified specialist workshop. The engine does not
start.

The starter motor
can be heard. The
reserve fuel warning
lamp is lit and the fuel
gauge display shows 0. The fuel tank is empty.
X
Refuel the vehicle. The engine does not
start. You cannot hear
the starter motor. The on-board voltage is too low because the battery is too weak
or discharged.
X
Jump-start the vehicle (Y page 308).
If the engine does not start despite attempts to jump-start it:
X Consult a qualified specialist workshop. The starter motor was exposed to a thermal load that was too high.
X
Allow the starter motor to cool down for approximately two
minutes.
X Try to start the engine again.
If the engine still does not start:
X Consult a qualified specialist workshop, e.g. a Mercedes-Benz
Service Centre. Driving
149
Driving and parking Z

Problem Possible causes/consequences and
M SolutionsThe fuel filler flap can-
not be opened. The fuel filler flap is not unlocked.
or
The key battery is discharged.
X
Unlock the vehicle (Y page 75).
or
X Unlock the vehicle using the emergency key element
(Y page 75). The fuel filler flap is unlocked, but the opening mechanism is jam-
med.
X
Consult a qualified specialist workshop. Parking
Important safety notes
G
WARNING
Flammable material such as leaves, grass or
twigs may ignite if they come into contact with
hot parts of the exhaust system or exhaust
gas flow. There is a risk of fire.
Park the vehicle so that no flammable mate-
rial can come into contact with hot vehicle
components. In particular, do not park on dry
grassland or harvested grain fields. G
WARNING
If you leave children unattended in the vehi-
cle, they may be able to set the vehicle in
motion if, for example, they:
R release the parking brake
R shift

the automatic transmission out of park
position P or shift manual transmission into
neutral
R start the engine
In addition, they may operate vehicle equip-
ment and become trapped. There is a risk of
an accident and injury.
When leaving the vehicle, always take the key
with you and lock the vehicle. Never leave
children unattended in the vehicle. !
Always secure the vehicle correctly
against

rolling away. Otherwise, the vehicle
or its drivetrain could be damaged.
To ensure that the vehicle is secured against
rolling away unintentionally:
R the electric parking brake must be applied.
R on vehicles with manual transmission,
engage first gear or reverse gear.
R on vehicles with automatic transmission,
the transmission must be in position P and
the transmission position display must
show P in the multifunction display.
R the key must be removed from the ignition
lock.
R on uphill or downhill gradients, the front
wheels must be turned towards the kerb. Switching off the engine
Important safety notes G
WARNING
The automatic transmission switches to neu-
tral
position N when you switch off the engine.
The vehicle may roll away. There is a risk of
an accident.
After switching off the engine, always switch
to parking position P. Prevent the parked vehi-162
Parking
Driving and parking

Releasing
X
Pull handle :.
The red ! indicator lamp in the instru-
ment cluster goes out.
i You can only release the electric parking
brake when the key is in position 1 or 2 in
the ignition lock.
Applying automatically The electric parking brake is applied auto-
matically:
R
if DISTRONIC PLUS brings the vehicle to a
standstill (vehicles with automatic trans-
mission) or
R if
the HOLD function is keeping the vehicle
stationary.
In addition, at least one of the following con-
ditions must be fulfilled:
R the engine is switched off
R the driver's door is open and the seat belt
is not fastened
R there is a system malfunction
R the power supply is insufficient
R the vehicle is stationary for a lengthy
period.
The red ! indicator lamp in the instrument
cluster lights up.
i The electric parking brake is not automat-
ically applied if the engine is switched off
by the ECO start/stop function.
Releasing automatically i
The electric parking brake can only be
released automatically in vehicles with
automatic transmission.
The electric parking brake of your vehicle is
released

automatically when all of the follow-
ing conditions are fulfilled:
R the engine is running.
R the transmission is in position D or R.
R the seat belt is fastened.
R you depress the accelerator pedal. If the transmission is in position
R,
the tailgate
must be closed.
If your seat belt is not fastened, the following
conditions must be fulfilled to automatically
release the electric parking brake:
R the driver's door is closed.
R you have shifted out of transmission posi-
tion P or you have previously driven faster
than 3 km/h.
Emergency braking The vehicle can also be braked during an
emergency using the electric parking brake.
X
While driving, push handle :
of the electric
parking brake ( Y page 163).
i The vehicle is braked for as long as han-
dle : of the electric parking brake
pressed. The longer the electric parking
brake handle : is depressed, the greater
the braking force.
During braking:
R a warning tone sounds
R the Release parking brake message
appears
R the red ! indicator lamp in the instru-
ment cluster flashes
When

the vehicle has been braked to a stand-
still, the electric parking brake is engaged. Parking up the vehicle
If you leave the vehicle parked up for longer
than

four weeks, the battery may be damaged
by exhaustive discharging.
If you leave the vehicle parked up for longer
than six weeks, the vehicle may suffer dam-
age as a result of lack of use.
X Visit a qualified specialist workshop and
seek advice.
i You can obtain information about trickle
chargers from a qualified specialist work-
shop. 164
Parking
Driving and parking

X
Press the ball coupling in the direction of
the arrow until it engages behind the
bumper.
Indicator lamp ? goes out and the mes-
sage in the multifunction display disap-
pears. Trailer power supply
! You can connect accessories with a
power rating of up to 240 W to the perma-
nent
power supply and with a power rating
of up to 180 W to the power supply that is
switched on via the ignition lock.
The trailer battery may not be charged from
the power supply.
X To switch the connected power supply
on or off: turn the key in the ignition lock
to position 2 or 0 respectively.
When it leaves the factory, your vehicle's
trailer socket is equipped with a permanent
power supply and a power supply that is
switched on via the ignition lock.
The permanent power supply is supplied via
trailer socket pin 9.
The power supply that is switched on via the
ignition lock is supplied via trailer socket pin
10.
The trailer's permanent power supply is
switched

off in the event of low vehicle supply
voltage and after six hours at the latest.
You can find more information about instal-
ling the trailer electrics at a qualified special-
ist workshop. Bulb failure indicator for LED lamps
i If LED lamps are fitted in the trailer, an
error message may appear in the multi-
function

display even if there is no fault. The
reason for the error message could be that
the current has fallen below the minimum
of 50 mA. To ensure reliable operation of the bulb failure
indicator,

each LED chain in the trailer lighting
must be guaranteed a minimum current of
50 mA. Trailer with 7-pin connector
General notes Trailer with 7-pin connector: you can con-
nect

to the 13-pin socket on the ball coupling
using an adapter or, if necessary, an adapter
cable. Both can be obtained at a qualified
specialist workshop.
Fitting the adapter !
Make sure that there is sufficient cable
play so that the cable cannot become
detached when cornering.
! Remove the installed adapter cable
before folding in the ball coupling. Other-
wise, damage may occur to the rear
bumper and the adapter cable. X
Open the socket cover.
X Insert the plug connector with lug : into
groove =

on the socket. Turn bayonet con-
nection ; clockwise to the stop.
X Let the cover engage.
X If you are using an adapter cable, secure
the cable to the trailer with cable ties.206
Towing a trailer
Driving and parking

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