check engine MERCEDES-BENZ A CLASS 2012 User Guide

Problem Possible causes/consequences and
M SolutionsThe engine cannot be
started using the key. The on-board voltage is too low.
X
Switch off non-essential consumers, e.g. seat heating or interior
lighting, and try to start the engine again.
If this does not work:
X Check the starter battery and charge it if necessary
(Y page 304).
or
X Jump-start the vehicle (Y page 308).
or
X Consult a qualified specialist workshop. The engine cannot be
started using the key. The steering lock is mechanically blocked.
X
Remove the key and reinsert it into the ignition lock. While doing
this, turn the steering wheel in both directions. Doors
Important safety notes
G
WARNING
If children are left unsupervised in the vehicle,
they could:
R open the doors, thus endangering other
people or road users.
R get out and disrupt traffic.
R operate the vehicle's equipment.
Additionally, children could set the vehicle in
motion if, for example, they:
R release the parking brake.
R shift the automatic transmission out of
parking position P.
R shift the manual transmission into neutral.
R start the engine.
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 or animals unattended in the vehicle.
Always keep the key out of reach of children. G
WARNING
If persons (particularly children) are exposed
to heat or cold for a prolonged period, there
is

a risk of serious or even fatal injuries. Never
leave persons (particularly children) unatten-
ded in the vehicle.
United Kingdom only: G
WARNING
When the double locks are activated, the
doors can no longer be opened from the
inside.

People in the vehicle can no longer get
out, e.g. in hazardous situations. There is a
risk of injury.
Therefore, do not leave any people unsuper-
vised in the vehicle, particularly children, eld-
erly people or people in need of special assis-
tance. Do not activate the double lock when
people are in the vehicle.
If the vehicle has been locked with the key,
then the double lock function is activated as
standard. You can deactivate the double lock
function by deactivating the interior motion
sensor (Y page 70). The doors can then be
opened from the inside after the vehicle has
been locked from the outside. The anti-theft Doors
79
Opening and closing Z

Adjusting the seat backrest side bol-
sters
X
To set the side bolsters of the seat
backrest narrower: press button A.
X To set the side bolsters of the seat
backrest wider: press button B. Steering wheel
Important safety notes
G
WARNING
You could lose control of the vehicle while
driving if you:
R adjust the driver's seat, steering wheel or
mirrors
R fasten the seat belt
There is a risk of an accident.
Adjust
the driver's seat, head restraint, steer-
ing wheel and mirrors and fasten your seat
belt before starting the engine. G
WARNING
Children could become trapped by the steer-
ing wheel if they adjust it. There is a risk of
injury.
When

leaving the vehicle, always take the key
with you and lock the vehicle. Never leave
children unattended in the vehicle. Adjusting the steering wheel
G
WARNING
The steering wheel may move unexpectedly if
you adjust it while driving. This could cause
you to lose control of the vehicle. There is a
risk of an accident.
Make sure that the steering wheel is locked
before driving off. Never unlock the steering
wheel when the vehicle is in motion. :
Release lever
; To adjust the steering wheel height
= To adjust the steering wheel position
(fore-and-aft adjustment)
X Push release lever : down completely.
The steering column is unlocked.
X Adjust the steering wheel to the desired
position.
X Push release lever : up completely.
The steering column is locked.
X Check if the steering column is locked.
When doing so, try to push the steering
wheel up or down or try to move it in the
fore-and-aft direction. Mirrors
Rear-view mirror
X
Anti-dazzle mode: pivot anti-dazzle
switch : forwards or back. 98
Mirrors
Seats, steering wheel and mirrors

The interior lighting is activated for a short
time when the key is removed from the igni-
tion lock. You can activate this delayed
switch-off using the on-board computer
(Y page 223).
Manual interior lighting control
X
To switch the front interior lighting on:
set the switch to the c position.
X To switch off the interior lighting: set the
switch to the | position or (if the door
is closed) to the centre position.
X To switch the rear interior lighting on/
off: press the u button.
X To switch the reading lamps on/off:
press the p button. Crash-responsive emergency lighting
The
interior lighting is activated automatically
if the vehicle is involved in an accident.
X To switch off the crash-responsive
emergency lighting: press the hazard
warning lamp button.
or
X Lock and then unlock the vehicle using the
key. Replacing bulbs
Important safety notes
Xenon bulbs G
DANGER
Xenon bulbs are under high voltage. You can
get
an electric shock if you remove the cover
of the xenon bulb and touch the electrical
contacts. There is a risk of fatal injury.
Never touch the parts or the electrical con-
tacts of the xenon bulb. Always have work on
the xenon bulbs carried out at a qualified spe-
cialist workshop. If your vehicle is equipped with xenon bulbs,
you can recognise this by the following: the
cone of light from the xenon bulbs moves
from the top to the bottom and back again
when you start the engine. For this to be
observed, the lights must be switched on
before starting the engine.
Bulbs and lamps are an important aspect of
vehicle

safety. You must therefore make sure
that these function correctly at all times.
Have the headlamp setting checked regularly.
Other bulbs G
WARNING
Bulbs, lamps and plug connectors can
become very hot during use. When replacing
a

bulb, you could burn yourself on these com-
ponents. There is a risk of injury.
Allow these components to cool down before
replacing the bulb.
There are bulbs other than the xenon bulbs
that you cannot replace. Replace only the
bulbs listed (Y page 113). Have the bulbs that
you cannot replace yourself replaced at a
qualified specialist workshop.
If you require assistance replacing bulbs, con-
sult a qualified specialist workshop.
Do not touch the glass tube of new bulbs with
your bare hands. Even minor contamination
can burn into the glass surface and reduce
the service life of the bulbs. Always use a lint-
free cloth or only touch the base of the bulb
when fitting.
Only use bulbs of the correct type.
If the new bulb still does not light up, consult
a qualified specialist workshop.
Bulbs and lamps are an important aspect of
vehicle safety. You must therefore make sure
that these function correctly at all times.
Have the headlamp setting checked regularly. 112
Replacing bulbs
Lights and windscreen wipers

Problems with the auxiliary heating/ventilation
Display messages Possible causes/consequences and
M Solutions$
FAIL The signal transmission between the transmitter and the vehicle
is faulty.
X
Change your position in relation to the vehicle, moving closer if
necessary.
X Make another attempt to switch the auxiliary heating on or off
using the remote control. ©
FAIL There is too little fuel in the fuel tank.
X
Refuel at the nearest filling station.
X Make another attempt to switch on the auxiliary heating using
the remote control. The auxiliary heating is faulty.
X
Have the auxiliary heating checked at a qualified specialist
workshop. FAIL The auxiliary heating cannot be switched on or has switched itself
off.
The
auxiliary heating was started more than twice when the engine
was switched off.
X Switch on the engine and let it run for more than ten seconds.
X Make another attempt to switch on the auxiliary heating using
the remote control. The auxiliary heating cannot be switched on or has switched itself
off.
The starter battery is not sufficiently charged.
X
Charge the starter battery.
X Make another attempt to switch on the auxiliary heating using
the remote control.138
Operating the climate control system
Climate control

more effort to steer and brake. There is a risk
of an accident.
Do not switch off the ignition while driving.
G
WARNING
If the parking brake has not been fully
released when driving, the parking brake can:
R overheat and cause a fire
R lose its hold function.
There is a risk of fire and an accident. Release
the parking brake fully before driving off.
! Warm up the engine quickly. Do not use
the engine's full performance until it has
reached operating temperature.
Only set the automatic transmission to the
respective drive positions when the vehicle
is stationary.
Where possible, avoid spinning the drive
wheels when pulling away on slippery
roads. Otherwise, you could damage the
drive train.
! AMG vehicles: avoid full-load operation
and engine speeds greater than 5000 rpm
when the engine is cold. This helps to pro-
tect the engine and avoids uncomfortable
driving. Key positions
g
To remove the key
1 Power supply for some consumers, such
as the windscreen wipers 2
Ignition (power supply for all consumers)
and drive position
3 To start the engine
Vehicles with manual transmission: the
steering is locked when the key is taken out
of the ignition lock.
i If the key does not belong to the vehicle,
it can still be turned in the ignition lock.
However, the ignition will not be switched
on. The engine cannot be started. Starting the engine
Important safety notes G
WARNING
Combustion engines emit poisonous exhaust
gases such as carbon monoxide. Inhaling
these

exhaust gases leads to poisoning. There
is a risk of fatal injury. Therefore never leave
the engine running in enclosed spaces with-
out sufficient ventilation. G
WARNING
Flammable materials introduced through
environmental influence or by animals can
ignite

if in contact with the exhaust system or
parts of the engine that heat up. There is a risk
of fire.
Carry out regular checks to make sure that
there are no flammable foreign materials in
the engine compartment or in the exhaust
system.
! Do not depress the accelerator pedal
when starting the engine.
i Vehicles with a petrol engine: the
engine runs at a higher engine speed during
the cold start procedure so that the cata-
lytic converter can reach operating tem-
perature more quickly. The sound of the
engine may change as a result. Driving
143
Driving and parking Z

Problem Possible causes/consequences and
M SolutionsVehicles with a petrol
engine:
The engine is not run-
ning smoothly and is
misfiring. There is a malfunction in the engine electronics or in a mechanical
component of the engine management system.
X
Only depress the accelerator pedal slightly.
Otherwise, non-combusted fuel may get into the catalytic con-
verter and damage it.
X Have the cause rectified immediately at a qualified specialist
workshop. The coolant tempera-
ture display is showing
more than 120
†. The
coolant warning lamp
may also be on and a
warning tone may
sound. The coolant level is too low. The coolant is too hot and the engine
is no longer being cooled sufficiently.
X
Stop as soon as possible and allow the engine and the coolant
to cool down.
X Check the coolant level (Y page 288). Observe the warning
notes as you do so and top up the coolant if necessary. If the coolant level is correct, the engine radiator fan may be faulty.
The coolant is too hot and the engine is no longer being cooled
sufficiently.
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. Manual transmission
Gear lever
! Only engage gear when the clutch pedal
is depressed.
! When shifting to 5th and 6th gear, you
must

press the shift lever to the right. Oth-
erwise, you could shift unintentionally into
3rd or 4th gear and damage the engine or
transmission.
If you shift down at too high a speed (trans-
mission braking), this can cause the engine
to overrev, leading to engine damage.
Do not use the clutch bite point to keep the
vehicle stationary on uphill gradients.
There is otherwise a risk of damaging the
clutch.
! On long and steep downhill gradients,
especially if the vehicle is laden or towing a trailer, you must shift into gear
1, 2 or 3
in
good time. This uses the engine's braking
effect. This relieves the load on the brake
system and prevents the brakes from over-
heating and wearing too quickly. Gear lever
k
Reverse gear
1 to 6 Forward gears150
Manual transmission
Driving and parking

j
Park position with parking lock
k Reverse gear
i Neutral
h Drive
i The DIRECT SELECT lever always returns
to its original position. The current trans-
mission
position P, R, N or D appears in the
transmission position display
(Y page 152) in the multifunction display.
Transmission position and drive pro-
gram display The current transmission position and drive
program appear in the multifunction display.
:
Transmission position display
; Drive program display
i The arrows in the transmission position
display

show how and into which transmis-
sion positions you can change using the
DIRECT SELECT lever.
! If the transmission position display in the
multifunction display is not working, you
should pull away carefully to check whether
the desired transmission position is
engaged. Ideally, you should select trans-
mission position D and drive program E or
S. Engaging park position P X
Push the DIRECT SELECT lever in the direc-
tion of arrow P.
Transmission

position display P is shown in
the multifunction display.
i When you engage park position P, make
sure

that the transmission position display
shows P in the multifunction display.
i You can only engage park position P when
the vehicle is stationary.
i The automatic transmission shifts into
park position P automatically:
R if you open the driver's door while the
vehicle is stationary in transmission posi-
tion D or R
R if you open the door while travelling at
very low speeds in transmission position
D or R
In addition, a warning tone sounds and a
display message is shown.
i Depressing the brake and pushing the
DIRECT SELECT lever up or down disen-
gages the parking lock. The transmission is
in N neutral.
At transmission fluid temperatures below
Ò20 †, you can only shift out of park posi-
tion P into another transmission position
when the engine is running.
In order to shift from park position P
directly into R or D:
R depress the brake pedal and
R push the DIRECT SELECT lever up or
down past the first point of resistance
! If the engine speed is too high, do not shift
the automatic transmission directly from
D to R, from R to D or directly to P. Other-
wise, the automatic transmission could be
damaged. 152
Automatic transmission
Driving and parking

Problems with the transmission
Problem Possible causes/consequences and
M SolutionsThe transmission has
problems shifting gear. The transmission is losing oil.
X
Have the transmission checked at a qualified specialist work-
shop immediately. The acceleration ability
is deteriorating.
The transmission no
longer shifts into all of
the gears.
Reverse gear can no
longer be engaged. The transmission is in emergency mode.
X
Stop.
X Shift the transmission to position P.
X Switch off the engine.
X Wait at least 10seconds before restarting the engine.
X Shift the transmission to position D.
X Have the transmission checked at a qualified specialist work-
shop immediately. Refuelling
Important safety notes
G
WARNING
Fuel is highly flammable. If you handle fuel
incorrectly, there is a risk of fire and explo-
sion.
You must avoid fire, naked flames, creating
sparks and smoking. Switch off the engine
and,
if applicable, the auxiliary heating before
refuelling. G
WARNING
Fuels are poisonous and hazardous to health.
There is a danger of injury.
Do

not swallow fuel or let it come into contact
with skin, eyes or clothing. Do not inhale fuel
vapours. Keep fuels out of the reach of chil-
dren.
If you or others come into contact with fuel,
observe the following:
R Wash the fuel off any affected areas of skin
with water and soap immediately.
R If you get fuel in your eyes, rinse them thor-
oughly with clean water immediately. Seek
immediate medical attention. R
If fuel is swallowed, seek immediate medi-
cal attention. Do not induce vomiting.
R Change any clothing that has come into
contact with fuel immediately. G
WARNING
Electrostatic charge can cause sparks and
thereby ignite fuel vapours. There is a risk of
fire and explosion.
Always

touch the vehicle body before opening
the fuel filler flap or touching the fuel pump
nozzle. This discharges any electrostatic
charge that may have built up. G
WARNING
Vehicles with a diesel engine:
If you mix diesel fuel with petrol, the flash
point

of this fuel mixture is lower than that of
pure diesel fuel. When the engine is running,
components in the exhaust system may over-
heat unnoticed. There is a risk of fire.
Never refuel with petrol. Never add petrol to
diesel fuel.
! Do not use petrol to refuel vehicles with a
diesel engine. Do not use diesel to refuel
vehicles with a petrol engine. Do not switch Refuelling
159
Driving and parking Z

cle from rolling away by applying the parking
brake.
Vehicles with manual transmission X
Shift to either first gear or reverse gear R.
X Turn the key to position 0 in the ignition
lock and remove it.
The immobiliser is activated.
X Apply the electric parking brake.
Vehicles with automatic transmission All vehicles (except AMG vehicles)
X
Apply the electric parking brake.
X Shift the transmission to position P.Selector lever in AMG vehicles
AMG vehicles:
X
Apply the electric parking brake.
X Press P button :.
X Turn the key to position 0 in the ignition
lock and remove it.
The immobiliser is activated.
i If you switch the engine off with the trans-
mission in position R or D, the automatic
transmission shifts to N automatically.
If you then open one of the front doors or
remove the key from the ignition, the auto-
matic transmission shifts to P.
If you shift the automatic transmission to
N before switching off the engine, the auto-
matic transmission remains in N even if a
door is opened. Electric parking brake
General notes G
WARNING
If you leave children unattended in the vehi-
cle, they could set the vehicle in motion by,
for example:
R releasing the parking brake
R shifting an automatic transmission out of
parking position P
R shifting

a manual transmission into neutral
R starting the engine
They could also operate vehicle equipment.
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. i
The electric parking brake carries out a
function check at regular intervals when
the engine is switched off. Noises that
occur are normal.
Engaging/releasing manually Engaging
X
Push handle :.
When
the electric parking brake is applied,
the ! red indicator lamp lights up in the
instrument cluster.
i The electric parking brake can also be
applied when the key is removed. Parking
163
Driving and parking Z

Cruise control lever
You can operate cruise control and variable
SPEEDTRONIC with the cruise control lever.
The LIM indicator lamp on the cruise control
lever
indicates which system you have selec-
ted:
R LIM indicator lamp off: cruise control is
selected.
R LIM indicator lamp on: variable SPEED-
TRONIC is selected. :
To activate or increase speed
; LIM indicator lamp
= To activate at the current speed/last
stored speed
? To activate or reduce speed
A To switch between cruise control and var-
iable SPEEDTRONIC
B To deactivate cruise control
When you activate cruise control, the stored
speed is shown in the multifunction display
for five seconds.
In the multifunction display, the segments
between

the stored speed and the maximum
speed light up.
Activation conditions To activate cruise control, all of the following
activation conditions must be fulfilled:
R
the electric parking brake must be
released.
R you are driving faster than 30 km/h. R
ESP ®
must be switched on, but not inter-
vening.
R on vehicles with automatic transmission,
the selector lever must be in position D.
R on vehicles with manual transmission, a
gear must be engaged.
R cruise control must be selected.
X To select cruise control: check whether
LIM indicator lamp ; is on or off.
If

it is off, cruise control is already selected.
X If it is not, press the cruise control lever in
the direction of arrow A.
LIM

indicator lamp ; in the cruise control
lever goes out. Cruise control is selected.
Storing, maintaining and calling up a
speed Storing and maintaining the current
speed
You can store the current speed if you are
driving faster than 30 km/h

.
X Accelerate the vehicle to the desired
speed.
X Briefly press the cruise control lever
up : or down ?.
X Remove your foot from the accelerator
pedal.
Cruise control is activated. The vehicle
automatically maintains the speed.
i Cruise
control may be unable to maintain
the stored speed on uphill gradients. The
stored speed is resumed when the gradient
evens out. Cruise control maintains the
stored speed on downhill gradients by
automatically braking the vehicle.
i Vehicles with manual transmission:
R always drive at adequate, but not exces-
sive, engine speeds.
R change gear in good time.
R if possible, do not change down several
gears at a time. Driving systems
169
Driving and parking Z