2012 MERCEDES-BENZ A CLASS park assist

trailer combination could also become unsta-
ble.
To avoid hazardous situations:
R
make
sure to check the noseweight before
each journey.
R use a drawbar noseweight as close as pos-
sible to the maximum noseweight.
R do not exceed the maximum permissible
noseweight.
R do not use a noseweight lower than the
minimum permissible trailer drawbar nose-
weight.
When reversing the vehicle towards the
trailer, make sure there is nobody between
the trailer and the vehicle.
Couple and uncouple the trailer carefully. If
you do not couple the trailer to the towing
vehicle correctly, the trailer could become
detached.
Make sure that the following values are not
exceeded:
R the permissible trailer drawbar noseweight
R the permissible trailer load
R the permissible rear axle load of the towing
vehicle
R the maximum permissible gross vehicle
weight of both the towing vehicle and the
trailer
The applicable permissible values, which
must not be exceeded, can be found:
R in your vehicle documents
R on the identification plates of the trailer tow
hitch and the trailer
R on the vehicle identification plate
If the values differ, the lowest value applies.
You will find the values approved by the man-
ufacturer on the vehicle identification plates
and those for the towing vehicle under "Tech-
nical data" ( Y page 349).
When towing a trailer, your vehicle's handling
characteristics will be different in comparison
to when driving without a trailer. The vehicle/trailer combination:
R
is heavier
R is restricted in its acceleration and gradi-
ent-climbing capability
R has an increased braking distance
R is affected more by strong crosswinds
R demands more sensitive steering
R has a larger turning circle
This can impair the vehicle's handling char-
acteristics.
Adapt your style of driving accord-
ingly. Maintain a safe distance. Drive care-
fully.
When towing a trailer, always adjust your
speed to the current road and weather con-
ditions. Do not exceed the maximum permis-
sible speed for your vehicle/trailer combina-
tion.
General notes X
When towing a trailer, set the tyre pressure
on the rear axle of the towing vehicle for a
maximum

load; see the tyre pressure table
in the fuel filler flap ( Y page 321).
Please note that when towing a trailer, PARK-
TRONIC ( Y page 182) and Blind Spot Assist
(Y

page 197) availability is limited or not avail-
able at all.
i The height of the ball coupling changes
with the load of the vehicle. If necessary,
use a trailer with a height-adjustable draw-
bar.
You will find fitting dimensions and loads
under "Technical data" ( Y page 348).
Driving tips i
Observe the notes on ESP ®
trailer stabi-
lisation ( Y page 68).
The

maximum permissible speed for vehicle/
trailer combinations depends on the type of
trailer. Before beginning the journey, check
the trailer's documents to see what the max-
imum permitted speed is. Observe the legally 202
Towing a trailer
Driving and parking

?
Menu bar
A Drive program (Y page 152)
B Transmission position ( Y page 152)
X To show the menu bar ?: press the
= or ; button on the steering wheel.
Menu bar ?
disappears after a few seconds.
Text field = shows the selected menu or
submenu as well as display messages.
i You can set the time using the audio sys-
tem or COMAND Online; see the separate
operating instructions.
The following messages may appear in the
multifunction display:
Z Gearshift recommendation, for
manual transmission
(Y

page 151) or automatic trans-
mission ( Y page 156)
XjY Active Parking Assist
(Y page 186)
¯ Cruise control ( Y page 168)
È SPEEDTRONIC ( Y page 171)
_ Adaptive Highbeam Assist
(Y page 110)
¤ ECO start/stop function
(Y page 146)
ë HOLD function ( Y page 179)
120 km/h! Maximum permissible speed
exceeded

(only for certain coun-
tries) Menus and submenus
Menu overview
Operating the on-board computer
(Y page 209).
Depending on the equipment fitted in the
vehicle, you can call up the following menus:
R Trip menu (Y page 211)
R Navi menu (navigation instructions)
(Y page 213)
R Audio menu (Y page 214) R
Tel (telephone) menu ( Y page 215)
R Assist (Assistance) menu (Y page 217)
R Serv. menu (Y page 219)
R Settings menu (Y page 220)
R AMG menu in AMG vehicles ( Y page 226)
The Audio, Navi

and Tel menus differ slightly
in vehicles with Audio 5, Audio 20 and in vehi-
cles with COMAND Online. The examples
given in this Owner's Manual apply to vehicles
equipped with COMAND Online. Trip menu
Standard display X
Press and hold the % button on the
steering wheel until the Trip menu with
trip meter : and total distance
recorder ; is shown.
Trip computer "From start" or "From
reset" Example: "From start" trip computer
:
Distance
; Time
= Average speed
? Average fuel consumption Menus and submenus
211
On-board computer and displays Z

Display messages Possible causes/consequences and
M SolutionsBlind Spot Assist is temporarily inoperative. Possible causes:
R
the sensors are dirty.
R the function is impaired due to heavy rain or snow.
R the radar sensor system is outside the operating temperature
range.
R the radar sensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio sta-
tions or other sources of electromagnetic radiation.
The yellow 9 indicator lamps also light up in the exterior mir-
rors.
Once
the causes listed above no longer apply, the display message
goes out.
Blind Spot Assist is operational again.
If the display message does not disappear:
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away ( Y page 162).
X Clean the sensors ( Y page 294).
X Restart the engine. Blind Spot Assist
inoperative Blind Spot Assist is faulty.
The yellow
9 indicator lamps also light up in the exterior mir-
rors.
X Visit a qualified specialist workshop. Park Assist cancel‐
led The driver's door is open and the driver's seat belt has not been
fastened.
X
Repeat the parking process with the seat belt fastened and the
driver's door closed. You inadvertently touched the multifunction steering wheel while
steering intervention was active.
X
While steering intervention is active, make sure not to touch the
multifunction steering wheel. The vehicle has started to skid and ESP
®
has intervened.
X Use Active Parking Assist again later (Y page 186).248
Display messages
On-board computer and displays

Display messages Possible causes/consequences and
M SolutionsPark Assist inoper‐
ative You have just carried out a large number of turning or parking
manoeuvres.
Active Parking Assist will become available again after approx-
imately ten minutes (
Y page 186).
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Switch off and restart the engine.
If the display message continues to be displayed:
X Visit a qualified specialist workshop. PARKTRONIC is faulty.
X
Visit a qualified specialist workshop. DISTRONIC PLUS off DISTRONIC PLUS has been deactivated (
Y page 173). If it was
deactivated automatically, a warning tone also sounds. DISTRONIC PLUS
available again DISTRONIC PLUS is operational again after having been tempo-
rarily unavailable. You can now reactivate DISTRONIC PLUS
(Y page 173).
DISTRONIC PLUS cur‐
rently
unavailable
See Owner's Manual DISTRONIC PLUS is temporarily inoperative. Possible causes:
R
the function is impaired due to heavy rain or snow.
R the sensors in the radiator trim are dirty
R the radar sensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio sta-
tions or other sources of electromagnetic radiation.
R the system is outside the operating temperature range.
R the on-board voltage is too low.
A warning tone also sounds.
Once
the causes listed above no longer apply, the display message
goes out.
DISTRONIC is operational again.
If the display message does not disappear:
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away ( Y page 162).
X Clean the sensors in the radiator trim (Y page 294).
X Restart the engine. Display messages
249
On-board computer and displays Z

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

and a tyre pressure that is too low can signif-
icantly impair the vehicle's braking and driv-
ing
characteristics. There is a risk of accident.
Do not continue driving. Contact a qualified
specialist workshop.
i In your vehicle, you will find a sticker with
the Mercedes-Benz Service24h telephone
number, e.g. on the B-pillar on the driver's
side.
X Correct the tyre pressure if it is still at least
130

kPa (1.3 bar/19 psi) (see the fuel filler
flap for values).
X To increase the tyre pressure:
switch on
the tyre inflation compressor. X
To reduce the tyre pressure: depress
pressure release button : next to pres-
sure gauge ;.X
To remove the tyre sealant bottle from the
tyre inflation compressor, press together
the locking tabs on the yellow cap.
X Pull the tyre sealant bottle out of the tyre
inflation compressor. The filler hose stays on the tyre sealant
bottle.
X Stow the tyre sealant bottle, the tyre infla-
tion compressor and the warning triangle.
X Drive to the nearest qualified specialist
workshop

and have the tyre changed there.
X Have the tyre sealant bottle and the filler
hose replaced as soon as possible at a
qualified specialist workshop.
X Have the tyre sealant bottle replaced every
four years at a qualified specialist work-
shop. Battery (vehicle)
Important safety notes
Work on the battery, e.g. removing or instal-
ling, requires specialist knowledge and the
use of special tools. Therefore, always have
work

on the battery carried out at a qualified
specialist workshop. G
WARNING
Work carried out incorrectly on the battery
can, for example, lead to a short circuit and
damage

your vehicle's electronic system. This
can disrupt driving safety systems such as
ABS (anti-lock braking system) or ESP ®
(Elec-
tronic Stability Program).
R If ABS malfunctions, the wheels can lock
during braking. This limits the steerability
of the vehicle when braking and the braking
distance may increase. There is a risk of
accident.
R If ESP ®
malfunctions, the vehicle will not be
stabilised if it starts to skid or a wheel starts
to spin. There is a risk of accident.
You should therefore have all work involving
the battery carried out at a qualified specialist
workshop. G
WARNING
Electrostatic build-up can lead to the creation
of
sparks, which could ignite the highly explo-304
Battery (vehicle)
Breakdown assistance

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

The battery and the cover of the positive
terminal
clamp must be fitted securely dur-
ing operation.
Comply with safety precautions and take pro-
tective measures when handling batteries. WARNING
Fire, naked flames and smoking
are prohibited when handling the
battery. Avoid creating sparks.
Battery acid is caustic. Avoid con-
tact

with the skin, eyes or clothing.
Wear suitable protective clothing,
in particular gloves, an apron and
a face mask.
Immediately rinse acid splashes
off with clean water. Consult a doc-
tor if necessary. Wear eye protection.
Keep children away.
Observe this Owner's Manual.
For safety reasons, Mercedes-Benz recom-
mends
that you only use batteries which have
been tested and approved for your vehicle by
Mercedes-Benz. These batteries provide
increased impact protection to prevent vehi-
cle occupants from suffering acid burns
should the battery be damaged in the event
of an accident.
In order for the battery to achieve the maxi-
mum possible service life, it must always be
sufficiently charged.
Like other batteries, the vehicle battery may
discharge over time if you do not use the
vehicle. In such cases, have the battery dis-
connected at a qualified specialist workshop. You can also charge the battery with a
charger recommended by Mercedes-Benz.
For

more information, please contact a quali-
fied specialist workshop.
Have the battery charge checked more fre-
quently if you use the vehicle mainly for short
trips or if you leave it standing idle for a
lengthy period. Consult a qualified specialist
workshop if you wish to leave your vehicle
parked up for a long period of time.
i When you park the vehicle, remove the
key if you do not require any electrical con-
sumers. The vehicle will then use very little
energy, thus conserving battery power.
i If the power supply has been interrupted,
e.g. if the battery was discharged, you will
have to:
R set the clock (audio system/COMAND
Online, see the separate operating
instructions).
R reset the function for folding the exterior
mirrors in/out automatically, by folding
the mirrors out once ( Y page 99). Charging the battery
G
WARNING
During charging and jump-starting, explosive
gases
can escape from the battery. There is a
risk of an explosion.
Particularly avoid fire, naked flames, creating
sparks and smoking. Ensure there is sufficient
ventilation while charging and jump-starting.
Do not lean over a battery. 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. 306
Battery (vehicle)
Breakdown assistance