2012 MERCEDES-BENZ A CLASS lock

Display messages Possible causes/consequences and
M Solutionsj
Check trailer
hitch lock The trailer tow hitch is not correctly engaged.
A warning tone also sounds.
X
Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.
X Apply the electric parking brake.
X Engage the trailer coupling's ball coupling in the end position
(Y page 203).
Otherwise, the trailer may detach itself. Ð
Power
steering mal‐
function See Own‐
er's Manual The power steering assistance is faulty.
A warning tone also sounds.
G WARNING
You will need to use more force to steer.
There is a risk of an accident.
X Check whether you are able to apply the extra force required.
X If you are able to steer safely:
carefully drive on to a qualified
specialist workshop.
X If you are unable to steer safely:
do not drive on. Contact the
nearest qualified specialist workshop. &
inoperative Bat‐
tery low You have attempted to switch on the auxiliary heating or to acti-
vate

a departure time using the on-board computer after operating
the auxiliary heating twice.
X Let the engine run for 10 seconds.
The auxiliary heating is operational again. The on-board voltage is too low. The auxiliary heating has switched
itself off or cannot be switched on

(Y page 134).
X Drive for a longer distance.
The

battery is being charged. The auxiliary heating is operational
again as soon as the on-board electrical system voltage is suf-
ficient. &
inoperative

Refuel
vehicle There is too little fuel in the fuel tank. The auxiliary heating cannot
be switched on (
Y page 134).
X Refuel at the nearest filling station. Display messages
255
On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions&
inoperative See
Owner's Man. The auxiliary heating has a temporary malfunction or is faulty.
X
When the vehicle is on a level surface and the engine has cooled
down,
make up to four attempts to switch on the auxiliary heat-
ing, waiting several minutes between each attempt
(Y page 134).
X If the auxiliary heating does not switch on, consult a qualified
specialist workshop. Telephone No
service Your vehicle is outside the network provider's transmitter/
receiver range.
X
Wait until the mobile phone operational readiness symbol
appears in the multifunction display. ¥
Top

up washer fluid The washer fluid level in the washer fluid reservoir has dropped
below the minimum.
i
If, during the winter months, you do not add antifreeze to the
washer
fluid, it may freeze in the washer fluid container. In this
case, the Top up washer fluid display message may appear
in the multifunction display.
X Top up the washer fluid ( Y page 289).Wiper malfunction‐
ing The windscreen wipers are defective.
X
Visit a qualified specialist workshop. Hazard warning
lamps malfunction‐
ing The hazard warning lamps are faulty.
X
Visit a qualified specialist workshop. Key
Display messages Possible causes/consequences and
M Solutions+
Key does not
belong to vehicle You have put the wrong key in the ignition lock.
X
Use the correct key. +
Replace key The key needs to be replaced.
X
Visit a qualified specialist workshop.256
Display messages
On-board computer and displays

Safety systems
Problem Possible causes/consequences and
M SolutionsJ
The red brake system
warning
lamp is lit while
the engine is running. A
warning tone also
sounds. There is insufficient brake fluid in the brake fluid reservoir.
G WARNING
The braking efficiency may be impaired.
There is a risk of an accident.
X Pull over and stop the vehicle safely as soon as possible, paying
attention

to road and traffic conditions. Do not continue driving
under any circumstances.
X Secure the vehicle against rolling away ( Y page 162).
X Do not top up the brake fluid. Topping up will not rectify the
fault.
X Consult a qualified specialist workshop.
X Observe the additional display messages in the multifunction
display. !
The

yellow ABS warning
lamp is lit while the
engine is running. ABS (Anti-lock Brake System) has been deactivated due to a fault.
BAS
(Brake Assist), COLLISION PREVENTION ASSIST, ESP ®
(Elec-
tronic Stability Program), PRE-SAFE ®
, the HOLD function, hill start
assist, the adaptive brake lights and ESP ®
trailer stabilisation are
also therefore deactivated, for example.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
The

steerability and braking characteristics may be severely affec-
ted. The braking distance may increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop.
If the ABS control unit is faulty, there is also a possibility that other
systems, such as the navigation system or the automatic trans-
mission, will be unavailable. 258
Warning and indicator lamps in the instrument cluster
On-board computer and displays

Problem Possible causes/consequences and
M Solutions!
The
yellow ABS warning
lamp is lit while the
engine is running. ABS is temporarily unavailable. Therefore, BAS, COLLISION PRE-
VENTION
ASSIST, ESP ®
, EBD (electronic brake force distribution),
PRE-SAFE ®
, the HOLD function, hill start assist, the adaptive brake
lights and ESP ®
trailer stabilisation, for example, are also deacti-
vated.
Possible causes:
R Self-diagnosis is not yet complete.
R the on-board voltage may be insufficient
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The front and rear wheels could therefore
lock, for example, if you brake hard.
The

steerability and braking characteristics may be severely affec-
ted. The braking distance may increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is a risk of an accident.
X Carefully drive on a suitable stretch of road, making slight steer-
ing movements at a speed above 20 km/h.
The functions mentioned above are available again when the
warning lamp goes out.
If the warning lamp is still on:
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop. Warning and indicator lamps in the instrument cluster
259
On-board computer and displays Z

Problem Possible causes/consequences and
M Solutions!
The
yellow ABS warning
lamp is lit while the
engine is running. A
warning tone also
sounds. EBD is faulty. Therefore, ABS, BAS, COLLISION PREVENTION
ASSIST,
ESP®
, PRE-SAFE ®
, the HOLD function, hill start assist, the
adaptive brake lights and ESP ®
trailer stabilisation, for example,
are not available either.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The front and rear wheels could therefore
lock, for example, if you brake hard.
The

steerability and braking characteristics may be severely affec-
ted. The braking distance may increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop. J֌!
The red brake warning
lamp, the yellow ESP
®
and ESP ®
OFF warning
lamps and the yellow
ABS warning lamp are
lit while the engine is
running. ABS and ESP
®
are malfunctioning. Therefore, BAS, COLLISION
PREVENTION ASSIST, EBD, PRE-SAFE ®
, the HOLD function, hill
start assist, the adaptive brake lights and ESP ®
trailer stabilisa-
tion, for example, are not available either.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The front and rear wheels could therefore
lock, for example, if you brake hard.
The

steerability and braking characteristics may be severely affec-
ted. The braking distance may increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop.260
Warning and indicator lamps in the instrument cluster
On-board computer and displays

Problem Possible causes/consequences and
M Solutions?
The red coolant warn-
ing lamp comes on
while the engine is run-
ning.
The coolant level is too low.
If the coolant level is correct, the airflow to the engine radiator
may be blocked or the electric engine radiator fan may be mal-
functioning.
The coolant is too hot and the engine is no longer being cooled
sufficiently.
X
Observe the additional display messages in the multifunction
display.
X Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.
X Secure the vehicle against rolling away ( Y page 162).
X Leave the vehicle and keep a safe distance from the vehicle until
the engine has cooled down.
X Check the coolant level and top up the coolant (Y page 288).
Observe the warning notes as you do so.
X If you have to top up the coolant frequently, have the engine
cooling system checked.
X Make sure that the air supply to the engine radiator is not
blocked, e.g. by frozen slush.
X Do not start the engine again until the coolant temperature is
below
120 †. The engine may otherwise be damaged.
X Drive to the nearest qualified specialist workshop.
X Avoid heavy loads on the engine as you do so, e.g. driving in
mountainous terrain and stop-start traffic. ?
The red coolant warn-
ing lamp comes on
while the engine is run-
ning. A warning tone
also sounds.
The coolant temperature has exceeded 120

†. The airflow to the
engine radiator may be blocked or the coolant level may be too
low.
G WARNING
The engine is not being cooled sufficiently and may be damaged.
Never
drive with an overheated engine. Driving when your engine
is overheated can cause some fluids which may have leaked into
the engine compartment to catch fire.
Steam from an overheated engine can cause serious burns which
can occur just by opening the bonnet.
This poses a risk of injury.
X Observe the additional display messages in the multifunction
display.
X Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.
X Secure the vehicle against rolling away ( Y page 162).Warning and indicator lamps in the instrument cluster
265
On-board computer and displays Z

Problem Possible causes/consequences and
M SolutionsX
Leave the vehicle and keep a safe distance from the vehicle until
the engine has cooled down.
X Check the coolant level and top up the coolant (Y page 288).
Observe the warning notes as you do so.
X If you have to top up the coolant frequently, have the engine
cooling system checked.
X Make sure that the air supply to the engine radiator is not
blocked, e.g. by frozen slush.
X If the coolant temperature is below 120 †, you can continue
driving to the nearest qualified specialist workshop.
X Avoid heavy loads on the engine as you do so, e.g. driving in
mountainous terrain and stop-start traffic. Driving systems
Problem Possible causes/consequences and
M Solutions·
The red distance warn-
ing
lamp lights up while
the vehicle is in motion. The distance to the vehicle in front is too small for the speed
selected.
X
Increase the distance. ·
The red distance warn-
ing

lamp lights up while
the vehicle is in motion.
A warning tone also
sounds. You are approaching a vehicle or a stationary obstacle in your line
of travel at too high a speed.
X
Be prepared to brake immediately.
X Pay careful attention to the traffic situation. You may have to
brake or take evasive action.266
Warning and indicator lamps in the instrument cluster
On-board computer and displays

Useful information
i This Owner's Manual describes all mod-
els,
series and optional equipment for your
vehicle that were available at the time of
going to press. National variations are pos-
sible. Note that your vehicle may not be
equipped with all of the functions descri-
bed. This is also the case for systems and
functions relevant to safety.
i Read the information on qualified special-
ist workshops: (Y page 24). Loading guidelines
G
WARNING
If objects, luggage or loads are not secured or
not secured sufficiently, they could slip, tip
over

or be flung around and thereby hit vehicle
occupants. There is a risk of injury, especially
when braking or abruptly changing directions.
Always store objects so that they cannot be
flung around. Secure objects, luggage or
loads against slipping or tipping before the
journey. G
WARNING
Combustion engines emit poisonous exhaust
gases
such as carbon monoxide. If the tailgate
is open when the engine is running, particu-
larly if the vehicle is moving, exhaust fumes
could enter the passenger compartment.
There is a risk of poisoning.
Turn off the engine before opening the tail-
gate. Never drive with the tailgate open.
The handling characteristics of a laden vehi-
cle are dependent on the distribution of the
load within the vehicle. For this reason, you
should observe the following notes when
transporting a load:
R when transporting a load, never exceed the
maximum permissible gross vehicle weight or the permissible axle loads for the vehicle
(including occupants).
R the luggage compartment is the preferred
place to carry objects.
R position

heavy loads as far forwards as pos-
sible and as low down in the luggage com-
partment as possible.
R the load must not protrude above the upper
edge of the seat backrests.
R always place the load against the rear or
front seat backrests. Make sure that the
seat backrests are securely locked into
place.
R always place the load behind unoccupied
seats if possible.
R use the lashing eyelets and the luggage
nets to transport loads and luggage.
R only use lashing eyelets and fastening com-
ponents that are suitable for the weight and
size of the load.
R the maximum load capacity of the stowage
well under the luggage compartment floor
is 25 kg.
R secure the load with sufficiently strong and
wear-resistant lashing material. Pad sharp
edges for protection.
i Lashing material is available at any quali-
fied specialist workshop.
! Do not position the load on one part of the
folding luggage compartment floor only.
The maximum load capacity of the folding
luggage compartment floor is 100 kg.
Spread the weight evenly to avoid damag-
ing the luggage compartment floor. Place a
solid board under the load if necessary.
Please note that the load on the luggage
compartment floor will be increased when
the load is lashed down. 268
Loading guidelines
Stowing and features