wheel MERCEDES-BENZ A CLASS 2012 Repair Manual

Problems with PARKTRONIC
Problem Possible causes/consequences and
M SolutionsOnly the red segments
in the PARKTRONIC
warning
displays are lit.
You also hear a warning
tone for approximately
two seconds.
PARKTRONIC is deacti-
vated after approx-
imately five seconds,
and the indicator lamp
in the PARKTRONIC
button lights up. PARKTRONIC has malfunctioned and has switched off.
X
If problems persist, have PARKTRONIC checked at a qualified
specialist workshop. Only the red segments
in the PARKTRONIC
warning

displays are lit.
PARKTRONIC is deacti-
vated after approx-
imately five seconds. The PARKTRONIC sensors are dirty or there is interference.
X
Clean the PARKTRONIC sensors ( Y page 294).
X Switch the ignition back on. The problem may be caused by an external source of radio or
ultrasound waves.
X
See if PARKTRONIC functions in a different location. Active Parking Assist
Important safety notes Active Parking Assist is only an aid. It is not a
substitute

for your attention to the immediate
surroundings. The responsibility for safe
manoeuvring and parking remains with you.
Make sure that there are no persons, animals
or objects in range while manoeuvring and
parking. G
WARNING
The vehicle will veer out when parking and can
take
you onto sections of the oncoming lane.
As a result, you may collide with other road
users. There is a risk of an accident.
When parking, pay attention to other road
users. Stop the vehicle if necessary or cancel
the Active Parking Assist parking procedure.
! If unavoidable, you should drive over
obstacles such as kerbs slowly and not at a sharp angle. Otherwise, you may damage
the wheels or tyres.
Active

Parking Assist may also display spaces
not suitable for parking, e.g.:
R parking or stopping prohibitions
R in front of driveways or entrances and exits
R unsuitable surfaces
Parking tips:
R on narrow roads, drive as closely as possi-
ble past the parking space.
R parking spaces that are littered, overgrown
or partially occupied by trailer drawbars
might be identified incorrectly or not at all.
R snowfall or heavy rain may lead to a parking
space being measured inaccurately.
R pay attention to the PARKTRONIC
(Y page 184) warning messages during the
parking procedure. 186
Driving systems
Driving and parking

When driving at speeds below 30 km/h, you
will see parking symbol
; as a status indi-
cator
in the instrument cluster. When a park-
ing space has been detected, an arrow
towards the right or the left also appears.
Active Parking Assist only displays parking
spaces on the front-passenger side as stand-
ard. Parking spaces on the driver's side are
displayed as soon as the turn signal on the
driver's side is activated. When parking on the
driver's side, this must remain switched on
until you acknowledge the use of Active Park-
ing Assist by pressing the a button on the
multifunction steering wheel.
A parking space is displayed while you are
driving past it, and until you are approx-
imately 15 m away from it.
Parking G
WARNING
Active Parking Assist merely aids you by inter-
vening
actively in the steering. There is a risk
of accident if you do not apply the brakes
yourself.
Always apply the brakes yourself when park-
ing and manoeuvring.
Active Parking Assist does not support you
with parking spaces parallel to the direction
of travel if:
R the parking space is on a kerbstone
R the parking space is apparently blocked,
for example by foliage or grass paving
blocks
R the range of movement is too small
R the parking space is bordered by an obsta-
cle which is not clearly defined such as a
tree or a trailer
X Stop the vehicle when the parking symbol
shows the desired parking space in the
instrument cluster.
X Vehicles with manual transmission: shift to
reverse gear. Vehicles with automatic transmission: shift
into position R.
The Start Park Assist? Yes: OK No:
%

message appears in the multifunction
display.
X To cancel the procedure: press the
% button on the multifunction steering
wheel or pull away.
or
X To park using Active Parking Assist:
press

the a button on the multifunction
steering wheel.
The Park Assist active Accelerate
and brake Observe surroundings mes-
sage appears in the multifunction display.
X Release the multifunction steering wheel.
X Reverse the vehicle, being ready to brake
at all times. Do not exceed a maximum
speed of approximately

10 km/h when
reversing. Otherwise, Active Parking Assist
will be cancelled.
i In tight parking spaces, you will achieve
the best parking results by backing up as
far as possible. When doing so, also
observe the PARKTRONIC messages.
X Stop as soon as PARKTRONIC sounds the
continuous warning tone, if not before.
Manoeuvring

may be required in tight park-
ing spaces.
Vehicles with manual transmission: the Park
Assist active Engage forward gear
Observe

surroundings message appears in
the multifunction display.
Vehicles with automatic transmission: the
Park Assist active Select D Observe
surroundings message appears in the mul-
tifunction display.
X Vehicles with manual transmission: while
the vehicle is stationary, shift to first gear.
Vehicles with automatic transmission:
select transmission position D while the
vehicle is stationary.
Active

Parking Assist immediately steers in
the other direction. 188
Driving systems
Driving and parking

The Park Assist active Accelerate
and
brake Observe surroundings mes-
sage appears in the multifunction display.
i You will achieve the best results by wait-
ing

for the steering procedure to complete
before pulling away.
X Drive forwards and be ready to brake at all
times.
X Stop as soon as PARKTRONIC sounds the
continuous warning tone, if not before.
Vehicles with manual transmission: the Park
Assist active Engage reverse gear
Observe

surroundings message appears in
the multifunction display.
Vehicles with automatic transmission: the
Park Assist active Select R Observe
surroundings message appears in the mul-
tifunction display.
X Additional transmission shifts may be nec-
essary.
As soon as the parking procedure is com-
plete, the Park Assist switched off
message appears in the multifunction dis-
play.
Active Parking Assist is then deactivated.
PARKTRONIC is still available.
X Manoeuvre if necessary.
X Always observe the warning messages dis-
played by PARKTRONIC

(Y page 184).
Parking tips:
R the way your vehicle is positioned in the
parking space after parking is dependent
on various factors. These include the posi-
tion and shape of the vehicles parked in
front

and behind it and the conditions of the
location. It may be the case that Active
Parking Assist guides you too far into a
parking space, or not far enough into it. In
some cases, it may also lead you across or
onto the kerb. If necessary, you should can-
cel the parking procedure with Active Park-
ing Assist.
R you can also engage forward gear prema-
turely. The vehicle redirects and does not
drive as far into the parking space. Should a gear be changed too early, the parking
procedure will be cancelled. A sensible
parking

position can no longer be achieved
from this position.
Exiting a parking space In order that Active Parking Assist can sup-
port you when you exit the parking space:
R
the border of the parking space must not
be too low.
R the border of the parking space must not
be too wide. The system manoeuvres the
vehicle

into a position at a maximum of 45°
to the starting position in the parking
space.
R a manoeuvring distance of at least 0.60 m
must be available.
Active Parking Assist can only assist you with
exiting a parking space if you have parked the
vehicle using Active Parking Assist.
X Start the engine.
X Switch on the turn signal on the side facing
the street.
X Vehicles with manual transmission:
engage first or reverse gear.
Vehicles with automatic transmission:
shift the transmission to position D or R.
The Start Park Assist? Yes: OK No:
%

message appears in the multifunction
display.
X To cancel the procedure: press the
% button on the multifunction steering
wheel or pull away.
or
X To exit a parking space using Active
Parking Assist: press the a button on
the multifunction steering wheel.
The Park Assist active Accelerate
and

brake Observe surroundings mes-
sage appears in the multifunction display.
X Release the multifunction steering wheel.
X Reverse the vehicle or drive forwards, being
ready to brake at all times. Do not exceed
a maximum speed of approximately Driving systems
189
Driving and parking Z

10 km/h when exiting a parking space.
Otherwise, Active Parking Assist will be
cancelled.
X Stop when PARKTRONIC sounds the con-
tinuous warning tone, if not before.
X Vehicles with manual transmission:
shift to first or reverse gear as required
while the vehicle is stationary.
Vehicles with automatic transmission:
shift
to position D or R as required while the
vehicle is stationary.
Active Parking Assist immediately steers in
the other direction. The Park Assist
active Accelerate and brake
Observe surroundings message appears
in the multifunction display.
i You will achieve the best results by wait-
ing

for the steering procedure to complete
before pulling away.
If you reverse after activation, the steering
wheel is moved to the straight-ahead posi-
tion.
X Drive forwards or reverse the vehicle, being
ready to brake at all times.
X Stop as soon as PARKTRONIC sounds the
continuous warning tone, if not before.
X Drive forwards and reverse as prompted by
the

PARKTRONIC warning displays, several
times if necessary.
Once you have exited the parking space com-
pletely, the steering wheel is moved to the
straight-ahead position. You hear a tone and
the Park Assist switched off message
appears

in the multifunction display. You will
then have to steer and merge into traffic on
your own. PARKTRONIC is still available. Cancelling Active Parking Assist You can cancel Active Parking Assist at any
time.
X
Stop the movement of the multifunction
steering wheel or steer yourself.
Active Parking Assist will be cancelled at
once. The Park Assist cancelled mes-
sage appears in the multifunction display.
or
X Press the PARKTRONIC button on the
centre console

(Y page 185).
PARKTRONIC is switched off and Active
Parking Assist is immediately cancelled.
The Park Assist cancelled message
appears in the multifunction display.
Active Parking Assist is cancelled automati-
cally if:
R you engage the electric parking brake.
R parking using Active Parking Assist is no
longer possible.
R you are driving faster than 10 km/h.
R a

wheel spins and ESP ®
intervenes or fails.
The ÷ warning lamp lights up in the
instrument cluster.
A warning tone sounds. The parking space
symbol disappears and the multifunction dis-
play shows the Park Assist cancelled
message.
When Active Parking Assist is cancelled, you
must steer again yourself.
If a system malfunction occurs, the vehicle is
braked to a standstill. To drive on, depress the
accelerator again.
Towing a trailer For vehicles with a trailer tow hitch, the min-
imum required length for parking spaces is
slightly increased.
If you have attached a trailer to your vehicle,
you should not use Active Parking Assist.
Once

the electrical connection is established
between your vehicle and the trailer, Active
Parking Assist is no longer available. PARK-
TRONIC is deactivated for the rear area. 190
Driving systems
Driving and parking

function; see the separate COMAND Online
operating instructions.
or
X Select symbol ; for the coupling up a
trailer
function (see the separate COMAND
Online operating instructions).
The symbol of the selected function is high-
lighted.
To deactivate:
the reversing camera is deac-
tivated if you:
R select transmission position P (vehicles
with automatic transmission)
R drive forward ten metres
R for vehicles with an automatic transmis-
sion, shift the transmission from R to
another position after 15 seconds
R shift out of reverse gear (vehicles with man-
ual transmission) after 15 seconds
R drive forwards at a speed of over
10 km/h
Displays in the Audio/COMAND display The reversing camera may show a distorted
view of obstacles, show them incorrectly or
not at all. Obstacles are not shown by the
reversing camera in the following locations:
R
very close to the rear bumper
R under the rear bumper
R in the area immediately above the tailgate
handle
! Objects

not at ground level may appear to
be further away than they actually are, e.g.:
R the bumper of a parked vehicle
R the drawbar of a trailer
R the ball coupling of a trailer tow hitch
R the rear section of an HGV
R a slanted post
Use the guidelines only for orientation.
Approach objects no further than the bot-
tom-most guideline. Lanes
:
White guide line without turning the steer-
ing wheel, vehicle width including the
exterior mirrors (static)
; Yellow lane marking the course the tyres
will take at the current steering wheel
angle, vehicle width including the outer
edge of the wheel (dynamic)
= Red guide line for the vehicle width includ-
ing

the exterior mirrors, for current steer-
ing wheel angle (dynamic)
? Bumper Guide lines
?
Bumper
A Red guide line at a distance of approx-
imately

0.25 m from the rear of the vehicle
B Yellow guide line at a distance of approx-
imately

4.0 m from the rear of the vehicle
C Vehicle centre axle (marker assistance)
D Yellow guide line at a distance of approx-
imately

1.0 m from the rear of the vehicle
The lanes and guide lines are only displayed
if you have engaged reverse gear. 192
Driving systems
Driving and parking

The distance specifications only apply to
objects that are at ground level.
Additional displays on vehicles with PARKTRONIC
and COMAND Online
:
Front warning display
; Additional PARKTRONIC operational read-
iness indicator
= Rear warning display
Vehicles with PARKTRONIC and COMAND
Online: when PARKTRONIC is operational
(Y page 182), additional operational readi-
ness indicator ; appears in the COMAND
display.If the PARKTRONIC warning displays
are
active or light up, warning displays : and
= are also active or light up correspondingly
in the COMAND display.
Reverse parking function X
Make sure that the reversing camera is
activated and the "Reverse parking" func-
tion

is selected; see the separate operating
instructions for the audio system/
COMAND Online.
The lane and the guide lines are shown. Reversing straight into a parking space
without turning the steering wheel :
White lane indicating the route the vehicle
will take with the steering wheel straight
; Yellow guide line at a distance of approx-
imately

1.0 m from the rear of the vehicle
= Red guide line at a distance of approx-
imately

0.25 m from the rear of the vehicle
X With the help of white lane :, check
whether
the vehicle will fit into the parking
space.
X Using the white lane as a guide, carefully
reverse until you reach the end position.
Red guide line = is then at the end of the
parking

space. The vehicle is almost paral-
lel in the parking space.
Reverse perpendicular parking with the
steering wheel at an angle
X Drive past the parking space and bring the
vehicle to a standstill. Driving systems
193
Driving and parking Z

Turning the steering wheel
:
Red lane indicating the route the vehicle
will
take with the steering wheel in its cur-
rent position
; Parking space marking
X While the vehicle is at a standstill, turn the
steering

wheel in the direction of the park-
ing space until the red lane reaches parking
space marking ;.
X Keep the steering wheel in that position
and reverse carefully. Reversing with the steering wheel turned
:
Red lane indicating the route the vehicle
will

take with the steering wheel in its cur-
rent position
X Stop the vehicle when it is almost exactly
in front of the parking space.
The

white lane should be as close to parallel
with the parking space marking as possi-
ble. Driving to the final position
:
White lane indicating the route the vehicle
will

take with the steering wheel in its cur-
rent position
; Parking space marking
X Turn the steering wheel to the centre posi-
tion while the vehicle is stationary. :
Red guide line at a distance of approx-
imately

0.25 m from the rear of the vehicle
; White lane indicating the route the vehicle
will take with the steering wheel straight
= End of parking space
X Reverse carefully until you have reached
the end position.
Red guide line :

is then at end of parking
space =. The vehicle is almost parallel in
the parking space.
"Coupling up a trailer" function This function is only available on vehicles with
a trailer tow hitch and COMAND Online.194
Driving systems
Driving and parking

:
Lane Keeping Assist camera
If you select km on the on-board computer in
the Display unit Speed-/odometer func-
tion (Y page 220), Lane Keeping Assist is
active starting at a speed of 60 km/h
. If the
miles display unit is selected, the assistance
range begins at 40 mph.
Important safety notes G
WARNING
Lane Keeping Assist cannot always clearly
identify lane markings.
In these cases, Lane Keeping Assist may:
R give an unnecessary warning
R not give a warning
There is a risk of an accident.
Always pay particular attention to the traffic
situation and keep in lane, especially if Lane
Keeping Assist alerts you. G
WARNING
The Lane Keeping Assist warning does not
return the vehicle to the original lane. There
is a risk of an accident.
Always steer, apply the brakes or accelerate
the vehicle yourself, especially if Lane Keep-
ing Assist alerts you.
If you fail to adapt your driving style, Lane
Keeping

Assist can neither reduce the risk of
an accident nor override the laws of physics.
Lane Keeping Assist cannot take into account
road, weather or traffic conditions. Lane
Keeping Assist is only an aid. You are respon-
sible for the distance to the vehicle in front, for vehicle speed, for braking in good time,
and for staying in the lane.
Lane

Keeping Assist does not keep your vehi-
cle in its lane.
The system may be impaired or may not func-
tion if:
R there is poor visibility, e.g. due to insuffi-
cient illumination of the road, or due to
snow, rain, fog or spray
R there is glare, e.g. from oncoming traffic,
the sun or reflection from other vehicles
(e.g. if the road surface is wet)
R the windscreen is dirty, misted up, dam-
aged or covered, for instance by a sticker
in the vicinity of the camera
R no, or several, unclear lane markings are
present for one lane, e.g. in a construction
area
R the lane markings are worn away, dark or
covered up, e.g. by dirt or snow
R the distance to the vehicle in front is too
small and the lane markings thus cannot be
detected
R the lane markings change quickly, e.g.
lanes branch off, cross one another or
merge
R the road is narrow and winding
R there are highly variable shade conditions
on the road
A warning may be given if a front wheel
passes over a lane marking. It will warn you
by means of intermittent vibration in the
steering wheel for up to 1.5 seconds.
Activating Lane Keeping Assist
X Activate Lane Keeping Assist using the on-
board computer; to do so, select Stand‐
ard or Adaptive(Y page 219).
If you drive at speeds above

60 km/h and
lane markings are detected, the lane mark-
ings in the assistance graphics display
(Y page 217) are shown in green. 200
Driving systems
Driving and parking

prescribed maximum speed in the relevant
country.
For
certain Mercedes-Benz vehicles, the max-
imum permissible rear axle load is increased
when towing a trailer. Refer to the "Technical
data" section to find out whether this applies
to your vehicle. If you utilise any of the added
maximum rear axle load when towing a trailer,
the vehicle/trailer combination may not
exceed a maximum speed of 100 km/h for
reasons concerning the operating permit.
This also applies in countries in which the
permissible maximum speed for vehicle/
trailer combinations is above 100 km/h.
When towing a trailer, your vehicle's handling
characteristics will be different in comparison
to when driving without a trailer and it will
consume more fuel.
Change into a lower gear in good time on long
and steep downhill gradients. For vehicles
with automatic transmission, you need to
have selected manual drive program
M(Y page 156).
i This also applies if you have activated
cruise control, SPEEDTRONIC or DIS-
TRONIC PLUS.
This will use the braking effect of the engine,
so less braking will be required to maintain
vehicle speed. This relieves the load on the
brake system and prevents the brakes from
overheating and wearing too quickly. If you
need additional braking, depress the brake
pedal repeatedly rather than continuously.
i Briefly depressing the accelerator pedal
on downhill gradients while the manual
drive program M is temporarily activated
(vehicles with automatic transmission): the
automatic transmission may switch back to
the last active automatic drive program E
or S. The automatic transmission may shift
to a higher gear. This can reduce the
engine's braking effect. Driving tips If the trailer swings from side to side:
X
Do not accelerate.
X Do not countersteer.
X Brake if necessary.
R Maintain a greater distance from the vehi-
cle in front than when driving without a
trailer.
R Avoid braking abruptly. If possible, brake
gently

at first to allow the trailer to run on.
Then, increase the braking force rapidly.
R The values given for gradient-climbing
capabilities from a standstill refer to sea
level. When driving in mountainous areas,
note that the power output of the engine,
and consequently the vehicle's gradient-
climbing capability, decrease with increas-
ing altitude. Folding out the ball coupling
G
WARNING
If you release the ball coupling or it does not
engage
correctly when folding in, it will swing
out. Within pivoting range of the ball coupling,
there is an increased risk of an accident and
injury.
Only release the ball coupling if the pivoting
range is unobstructed. Always make sure that
the ball coupling engages when folding in.
Before you can tow a trailer with your vehicle,
you must fold out the ball coupling.
The release wheel is located behind the left-
hand side trim panel in the boot. Towing a trailer
203
Driving and parking Z

X
To open the cover: turn handle : anti-
clockwise and fold down cover ; and
remove it. X
Pull out release wheel =.
X Turn release wheel = anti-clockwise as far
as it will go.
The ball coupling disengages and folds out
behind the rear bumper. Indicator
lamp ? flashes. G
WARNING
If the ball coupling is not correctly engaged,
the trailer can detach. There is a risk of an
accident.
Always

engage the ball coupling as described.
X Pull the ball coupling in the direction of the
arrow

until it engages in a vertical position.
Indicator lamp ? goes out. The power
socket folds down automatically.
The multifunction display shows the
Check trailer hitch lock display mes-
sage until the ball coupling is engaged.
X Remove the protective covering from the
ball coupling and store it in a safe place.
X Make sure that the ball of the ball coupling
is clean and that it is either greased or dry
(grease free), depending on the instruc-
tions for the trailer. Coupling up a trailer
X Make sure that the transmission is in posi-
tion P.
X Apply the electric parking brake.
X Position the trailer level behind the vehicle.
X Couple up the trailer.
X Establish the electric connection between
the vehicle and the trailer.
X Check that the trailer lighting system is
working.
A trailer that is connected is recognised
only when the electrical connection is
established

correctly and when the lighting
system is working properly. The function of
other systems, such as ESP ®
or PARK-
TRONIC also depends on this. Uncoupling a trailer
G
WARNING
If you uncouple a trailer with an engaged over-
run
brake, you could trap your hand between204
Towing a trailer
Driving and parking