2012 MERCEDES-BENZ A CLASS sensor

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

alarm system is triggered if the door is
opened from the inside. Switch off the alarm
(Y page 69).
Unlocking and opening the doors
from the inside
X
Pull door handle ;.
If the door is locked, locking knob : pops
up. The door is unlocked and can be
opened.
For all countries except the United King-
dom:
You can open a door from inside the vehicle
even if it has been locked.
If

the vehicle has previously been locked with
the key, opening a door from the inside will
trigger the anti-theft alarm system. Switch off
the alarm ( Y page 69).
You can only open the rear doors from inside
the vehicle if they are not secured by the
child-proof locks (Y page 60).
Only for the United Kingdom: if the vehicle
has been locked with the key, the double lock
function is activated as standard. It is then
not possible to open the doors from inside the
vehicle. Deactivate the interior motion sensor
(Y page 70) before you lock the vehicle with
the key. The doors can then be opened from
the inside after the vehicle has been locked
from the outside. The anti-theft alarm system
is triggered if the door is opened from the
inside. Switch off the alarm (Y page 69). Centrally locking and unlocking the
vehicle from the inside
You can centrally lock or unlock the vehicle
from

the inside. This can be useful if you wish
to lock the vehicle before pulling away, for
example. X
To unlock: press button :.
X To lock: press button ;.
If all the doors and the tailgate are closed,
the vehicle locks.
This does not lock or unlock the fuel filler flap.
You cannot unlock the vehicle centrally from
the

inside if the vehicle has been locked with
the key.
For all countries except the United King-
dom: you can open a door from inside the
vehicle even if it has been locked.
If the vehicle has previously been locked with
the key, opening a door from the inside will
trigger the anti-theft alarm system. Switch off
the alarm ( Y page 69).
Only for the United Kingdom: if the vehicle
has been locked with the key, the double lock
function is activated as standard. It is then
not possible to open the doors from inside the
vehicle. Deactivate the interior motion sensor
(Y page 70) before you lock the vehicle with
the key. The doors can then be opened from
the inside after the vehicle has been locked
from the outside. The anti-theft alarm system
is triggered if the door is opened from the
inside. Switch off the alarm (Y page 69). 80
Doors
Opening and closing

tilation of the vehicle interior, you can raise
the sliding sunroof.
If contact is made with a roof carrier
approved by Mercedes-Benz, the sliding
sunroof lowers slightly but remains raised
at the rear.
Rain-closing feature The rain-closing feature is only available for
vehicles with a rain sensor.
When the key is in position 0 in the ignition
lock
or is removed, the sliding sunroof closes
automatically:
R if it starts to rain
R at extreme outside temperatures
R after six hours
R if there is a malfunction in the power supply
The sliding sunroof remains raised at the rear
in order to allow ventilation of the vehicle
interior.
i If the sliding sunroof is obstructed when
being closed by the rain-closing feature, it
opens again slightly. The rain-closing fea-
ture is then deactivated.
The sliding sunroof does not close if:
R it is raised at the rear.
R it is blocked.
R no rain is falling on the area of the wind-
screen being monitored by the rain sensor,
e.g. because the vehicle is under a bridge. Operating the roller sunblinds for the
sliding sunroof
Important safety notes G
WARNING
When opening or closing the roller sunblind
parts of the body could be trapped between
the roller sunblind and the frame or sliding
sunroof. There is a risk of injury. When opening or closing make sure that no
parts

of the body are in the sweep of the roller
sunblind.
If someone is trapped:
R release the switch immediately or
R press the switch in any direction during the
automatic opening/closing process
The opening/closing process is stopped.
The roller sunblinds shield the vehicle interior
from sunlight. The two roller sunblinds can
only be opened and closed together when the
sliding sunroof is closed.
Roller sunblind reversing feature The roller sunblinds are equipped with an
automatic reversing feature. If a solid object
blocks or restricts the roller blind during the
closing process, the roller blind opens again
automatically. However, the automatic
reversing feature is only an aid and does not
relieve you of the responsibility to pay atten-
tion when closing the roller blinds.
G
WARNING
The reversing feature especially does not
react to soft, light and thin objects, such as
small fingers.This means that the reversing
feature cannot prevent someone being trap-
ped in these situations. There is a risk of
injury.
When closing make sure that no parts of the
body are in the sweep of the roller sunblind.
If someone is trapped:
R release the switch immediately or
R press

the switch in any direction during the
automatic opening/closing process
The closing process is stopped. 88
Panorama sliding sunroof
Opening and closing

Folding the exterior mirrors in/out
automatically
If the "Fold in mirrors when locking" function
is activated in the on-board computer
(Y page 225):
R
the
exterior mirrors fold in automatically as
soon as you lock the vehicle from the out-
side.
R the exterior mirrors fold out again automat-
ically as soon as you unlock the vehicle and
then open the driver's or front-passenger
door.
i If the exterior mirrors have been folded in
manually, they do not fold out.
Exterior mirror pushed out of position If an exterior mirror has been pushed out of
position, proceed as follows.
X
Vehicles without electrically folding
exterior

mirrors: move the exterior mirror
into the correct position manually.
X Vehicles with electrically folding exte-
rior mirrors: press and hold the mirror-
folding button

(Y page 99) until you hear a
click and then the mirror engage in posi-
tion.
The mirror housing is engaged again and
you can adjust the exterior mirrors as usual
(Y page 99). Automatic anti-dazzle mirrors
The "Automatic anti-dazzle mirrors" function
is

only available if the vehicle is equipped with
the "Mirror package".
The rear-view mirror and the exterior mirror
on the driver's side automatically go into anti-
dazzle mode if:
R the ignition is switched on and
R incident light from headlamps strikes the
sensor in the rear-view mirror
The mirrors do not go into anti-dazzle mode if
reverse gear is engaged or if the interior light-
ing is switched on. Parking position of the exterior mirror
on the front-passenger side
General notes The "Parking position for the exterior mirror
on the front-passenger side" function is only
available if the vehicle is equipped with the
"Memory package".
Setting

and storing the parking position Using reverse gear
You

can set the front-passenger side exterior
mirror so that you can see the rear wheel on
that side as soon as you engage reverse gear.
You can store this position. X
Make sure that the vehicle is stationary and
that the key is in position 2 in the ignition
lock.
X Press button ; for the exterior mirror on
the front-passenger side.
X Engage reverse gear.
The exterior mirror on the front-passenger
side moves to the preset parking position.
X Use adjustment button = to adjust the
exterior mirror. You should see the rear
wheel and the kerb in the exterior mirror.
The parking position is stored.
i If you shift the transmission to another
position, the exterior mirror on the front-
passenger side returns to the driving posi-
tion. 100
Mirrors
Seats, steering wheel and mirrors

Setting the exterior lighting
Setting options Exterior lighting can be set using the:
R
light switch
R headlamp range control (vehicles with hal-
ogen headlamps only)
(Y page 107)
R combination switch (Y page 107)
R on-board computer (Y page 221)
Light switch Operation
1W
Left-hand parking lamps
2X Right-hand parking lamps
3T Side lamps, licence plate and instru-
ment cluster lighting
4Ã Automatic headlamp mode, control-
led by the light sensor
5L Dipped-beam/main-beam head-
lamps
BR Rear foglamp
CN Foglamp (vehicles with front fog-
lamps only)
If you hear a warning tone when you leave the
vehicle, the lights may still be switched on.
X Turn the light switch to Ã.
The exterior lighting (except the side lamps/
parking lamps) switches off automatically if
you:
R remove the key from the ignition lock
R open

the driver's door with the key in posi-
tion 0. Automatic headlamp mode G
WARNING
When the light switch is set to Ã, the
dipped-beam
headlamps may not be switched
on automatically if there is fog, snow or other
causes of poor visibility due to the weather
conditions such as spray. There is a risk of an
accident.
In such situations, turn the light switch to
L.
The automatic headlamp feature is only an
aid. The driver is responsible for the vehicle's
lighting at all times.
à is the preferred light switch setting. The
light setting is automatically selected accord-
ing to the brightness of the ambient light
(exception: poor visibility due to weather con-
ditions such as fog, snow or spray):
R Key in position 1 in the ignition lock: the
side lamps are switched on or off automat-
ically depending on the brightness of the
ambient light.
R With the engine running: if you have
switched on the daytime driving lights func-
tion in the on-board computer, the daytime
driving lights or the side lamps and dipped-
beam headlamps are switched on or off
automatically depending on the brightness
of the ambient light.
X To switch on automatic headlamp
mode: turn the light switch to Ã.
The daytime driving lights improve the detect-
ability of your vehicle during the day. Here,
the daytime driving lights function must be
switched on via the on-board computer
(Y page 221).
When the dipped-beam headlamps are
switched on, the L indicator lamp in the
instrument cluster lights up and the daytime
driving lights switch off.
Dipped-beam headlamps
When

the ignition is switched on and the light
switch is in position L, the side lamps and
dipped-beam headlamps are switched on Exterior lighting
105
Lights and windscreen wipers Z

even if the light sensor does not sense dark
ambient light conditions. This is advanta-
geous when there is fog or rain.
X
To switch on the dipped-beam head-
lamps: turn the key in the ignition lock to
position 2 or start the engine.
X Turn the light switch to L.
The green L indicator lamp in the instru-
ment cluster lights up.
Foglamps
In conditions where visibility is poor due to
fog, snow or rain, the foglamps improve visi-
bility

as well as making it easier for other road
users to see you. They can be operated
together with the side lamps or together with
the side lamps and dipped-beam headlamps.
X To switch on the foglamps: turn the key
in

the ignition lock to position 2 or start the
engine.
X Turn the light switch to L or Ã.
X Press the N button.
The

green N indicator lamp in the instru-
ment cluster lights up.
X To switch off the front foglamps: press
the N button.
The

green N indicator lamp in the instru-
ment cluster goes out.
Only vehicles with front foglamps are equip-
ped with the "Foglamp" function; for how to
operate the foglamps on vehicles with the
Intelligent Light System

(Y page 109).
Rear foglamp
The rear foglamp improves the visibility of
your vehicle in heavy fog for the following
traffic. Please observe the country-specific
laws on the use of rear foglamps.
X To switch on the rear foglamp: turn the
key
in the ignition lock to position 2 or start
the engine.
X Turn the light switch to L or Ã.X
Press the R button.
The yellow R indicator lamp in the
instrument cluster lights up.
X To switch off the rear foglamp:
press the
R button.
The yellow R indicator lamp in the
instrument cluster goes out.
i Vehicles with bi-xenon headlamps or the
Intelligent

Light System: when the rear fog-
lamp is switched on, the lower 15 LEDs of
the brake lamp in the tail lamp switch off
due to a legal requirement: for right-hand
traffic only in the left-hand tail lamp and for
left-hand traffic only in the right-hand tail
lamp.
Side lamps
! If the battery has been excessively dis-
charged, the side lamps or parking lamps
are automatically switched off to enable
the next engine start. Always park your
vehicle safely and sufficiently lit according
to legal standards. Avoid the continuous
use of the T side lamps for several
hours. If possible, switch on the X right
or the W left parking lamp.
X To switch on: turn the light switch to
T.
Depending on the equipment level, the
green indicator lamp or the scale illumina-
tion in the instrument cluster light up.
Parking lamps
Switching on the parking lamps ensures the
corresponding side of the vehicle is illumina-
ted.
X To switch on the parking lamps: the key
is not in the ignition lock or it is in posi-
tion 0.
X Turn the light switch to W
(left-hand side
of the vehicle) or X (right-hand side of
the vehicle). 106
Exterior lighting
Lights and windscreen wipers

the illumination of the edge of the carriage-
way.
Active:
if you are driving at speeds below
70
km/h and you switch on the rear foglamp.
Not active: if you are driving at speeds above
100 km/h or if you switch off the rear foglamp
following activation. Adaptive Highbeam Assist
G
WARNING
Adaptive Highbeam Assist does not recognise
road users:
R who have no lights, e.g. pedestrians
R who have poor lighting, e.g. cyclists
R whose lighting is blocked, e.g. by a barrier
In

very rare cases, Adaptive Highbeam Assist
recognises road users too late or not at all. In
this, or in similar situations, the automatic
main-beam headlamps will not be deactivated
or activated regardless. There is a risk of an
accident.
Always carefully observe the traffic conditions
and switch off the main-beam headlamps in
good time.
You can use this function to set the head-
lamps to change between dipped beam and
main beam automatically. The system recog-
nises vehicles with their lights on, either
approaching from the opposite direction or
travelling in front of your vehicle, and conse-
quently switches the headlamps from main
beam to dipped beam.
The system automatically adapts the dipped-
beam headlamp range depending on the dis-
tance to the other vehicle. Once the system
no longer detects any other vehicles, it reac-
tivates the main-beam headlamps.
The system's optical sensor is located behind
the windscreen near the overhead control
panel. X
To activate: activate the Adaptive High-
beam Assist function using the on-board
computer (Y page 222).
X Turn the light switch to Ã.
X Press the combination switch beyond the
pressure point in the direction of
arrow : (Y page 107).
The _ indicator lamp in the multifunc-
tion

display lights up when it is dark and the
light sensor activates the dipped-beam
headlamps.
If you are driving at speeds above
45 km/h:
The headlamp range is set automatically
depending on the distance between the
vehicle and other road users.
If you are driving at speeds above
55 km/h and no other road users are rec-
ognised:
The main-beam headlamps are switched on
automatically. The K indicator lamp in
the instrument cluster also lights up.
If you are driving at speeds below
45 km/h or other road users are recog-
nised or the roads are adequately lit:
The main-beam headlamps are switched off
automatically. The K indicator lamp in110
Exterior lighting
Lights and windscreen wipers

X
Insert the new bulb into the bulb holder and
turn it clockwise.
X Secure the bulb holder to attachments =
on the lamp cluster and tighten plastic
nuts ?. X
Insert the lamp cluster into the vehicle and
make sure that it sits correctly in guides
F.
X Tighten wing nut ; and re-establish con-
tact with connector :.
X Close the side trim panel ( Y page 115).Windscreen wipers
Switching the windscreen wipers on/
off
! Do not operate the windscreen wipers
when the windscreen is dry, as this could
damage the wiper blades. Moreover, dust
that has collected on the windscreen can
scratch
the glass if wiping takes place when
the windscreen is dry.
If it is necessary to switch on the wind-
screen wipers in dry weather conditions,
always operate them using washer fluid.
! If the windscreen wipers leave smears on
the windscreen after the vehicle has been
washed in an automatic car wash, this may
be due to wax or other residue. Clean the
windscreen with washer fluid after an auto-
matic car wash. Combination switch
1
$ Windscreen wipers off
2 Ä Intermittent wipe, low (rain sensor
set to low sensitivity)
3 Å
Intermittent wipe, high (rain sensor
set to high sensitivity)
4 ° Continuous wipe, slow
5 ¯ Continuous wipe, fast
B í
Single wipe/ î to wipe the wind-
screen using washer fluid
X Turn the key to position 1
or 2 in the ignition
lock.
X Turn the combination switch to the corre-
sponding position.
! Vehicles with a rain sensor: if the wind-
screen becomes dirty in dry weather con-
ditions,

the windscreen wipers may be acti-
vated inadvertently. This could damage the
windscreen wiper blades or scratch the
windscreen.
For this reason, you should always switch
off the windscreen wipers in dry weather.
Vehicles with a rain sensor: in the Ä or
Å position, the appropriate wiping fre-
quency is automatically set according to the
intensity of the rain. In the Å position, the
rain sensor is more sensitive than in
the Ä position, causing the windscreen
wipers to wipe more frequently.
If the wiper blades are worn, the windscreen
will no longer be wiped properly. This could
prevent you from observing the traffic condi-
tions. Replace the wiper blades twice a year,
ideally in spring and autumn. Windscreen wipers
117Lights and windscreen wipers Z