tow MERCEDES-BENZ B-CLASS HATCHBACK 2011 Service Manual

When
Standard is selected, no warning vibra-
tion occurs if:
R you have switched on the turn signals. In
this event, the warnings are suppressed for
a certain period of time.
R a driving safety system intervenes, such as
ABS, BAS or ESP ®
.
When Adaptive is selected, no warning vibra-
tion occurs if:
R you have switched on the turn signals. In
this case, the warnings are suppressed for
a certain period of time.
R a driving safety system intervenes, such as
ABS, BAS or ESP ®
.
R you accelerate hard, e.g. kickdown.
R you brake hard.
R you steer actively, e.g. swerve to avoid an
obstacle or change lane quickly.
R you cut the corner on a sharp bend.
In order that you are warned only when nec-
essary and in good time if you cross the lane
marking, the system recognises certain con-
ditions and warns you accordingly.
The warning vibration occurs earlier if:
R you approach the outer lane marking on a
bend.
R the road has very wide lanes, e.g. a motor-
way.
R the system recognises solid lane markings.
The warning vibration occurs later if:
R the road has narrow lanes.
R you cut the corner on a bend. Towing
atrailer Notes on towing
atrailer
Important safety notes G
WARNING
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 no tcouple 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
You will find the applicable permissible val-
ues, which must not be exceeded, in the vehi-
cle documents.
You will find the values approved by the man-
ufacturer on the vehicle identification plates
and those for the towing vehicle in the "Tech-
nical data" section. G
WARNING
If the Check trailer hitch locking mechanism message appears in the multi-
function display while the vehicle is in motion,
pull over immediately and check whether the
ball coupling is correctly engaged. G
WARNING
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
As a result, the handling characteristics may
be impaired and you may lose control of the
vehicle. This could lead to an accident with
serious or even fatal injuries. Towing
atrailer
181Driving an d parking
Z

When towing a trailer, always adjust your
speed to the curren
troad and weather con-
ditions. Do not exceed the maximum permis-
sible speed for your vehicle/trailer combina-
tion. G
WARNING
Never depress the brake pedal continuously
while the vehicle is in motion, e.g. never cause
the brakes to rub by applying constant slight
pedal pressure. This causes the brake system
to overheat, increases the braking distance
and can lead to the brakes failing completely. G
WARNING
On no account should you attempt to draw the
vehicle/trailer combination out by increasing
speed. G
WARNING
If you exceed the maximum noseweight when
using a carrier system on the ball coupling:
R the carrier system may be thrown around.
R the ball coupling and the carrier system
may become detached from the vehicle.
As a result, you may injure others or cause an
accident.
Do not exceed the maximum noseweight.
When driving with a loaded carrier system,
always adjust your driving style to the prevail-
ing road, traffic and weather conditions and
drive particularly carefully.
You can use carrier systems, e.g. bicycle
racks or load-bearing implements, on the ball
coupling. The maximum noseweight of 75kg
applies when using carrier systems on the ball
coupling.
General notes !
Use a drawbar noseweight as close as
possible to the maximum permissible nose-
weight. Do not use a noseweight of less
than 50kg, otherwise the trailer may come
loose. Note that the payload and the rear axle load
are reduced by the actual payload.
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 295).
You will find installation dimensions and loads
in the "Technical data" section
(Y page 318).
The maximum noseweight of the trailer draw-
bar on the ball coupling is 75 kg. The actual
noseweight may however not be higher than
the value which is given on the trailer tow
hitch or trailer identification plates. The low-
est weight applies.
Please note that when towing a trailer, PARK-
TRONIC (Y page 163) and Blind Spot Assist
(Y page 177) are only available with limita-
tions, or not 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.
Driving tips i
Observe the notes on ESP ®
trailer stabi-
lisation (Y page 67).
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
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 182
Towing
atrailerDriving an d parking

permissible maximum speed for vehicle/
trailer combinations is above 100 km/h.
When towing a trailer, your vehicle's handling
characteristics will be differen tincomparison
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. Vehicles with
automatic transmission: in order to do so, you
will need to have switched to manual drive
program Min advance (Y page 139).
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 prevent the
vehicle from gaining 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 Vehicles with automatic transmis-
sion: if the accelerator pedal is depressed
briefly on downhill gradients while manual
drive program Mis temporarily activated,
the automatic transmission may switch
back to the last active automatic drive pro-
gram Eor S.T he 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 counter-steer.
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
Make sure that the ball coupling is engaged,
either in its folded-out or folded-in position,
and that the indicator lamp is off.
Do not turn the release wheel when a trailer
is coupled up. Otherwise, the trailer might
detach.
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. X
To open the cover: turn handle:anti-
clockwise and fold down cover ;and
remove it. Towing
atrailer
183Driving an d parking Z

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. 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
G
WARNING
Do not disconnect a trailer with an engaged
overrun brake. Otherwise, your hand could
become trapped between the bumper and
trailer drawbar.
X Make sure that the transmission is in posi-
tion P.
X Engage the electric parking brake.
X Position the trailer level behind the vehicle.
X Couple up the trailer.
X Establish the electrical connection
between the vehicle and the trailer.
X Check that the trailer lighting system is
working. Decoupling
atrailer G
WARNING
As soon as you raise the trailer drawbar, the
unladen vehicle rises slightly. The vehicle then
lowers to driving level.
Make sure tha tnobody is in the vicinity of the
wheel arch or the underbody. You could oth-
erwise trap yourself or others. G
WARNING
The vehicle is lowered as soon as you discon-
nect the trailer cable. Make sure that nobody
is in the vicinity of the wheel arch or the
underbody. You could otherwise trap yourself
or others.
As soon as you decouple the trailer, the unla-
den vehicle rises slightly. Make sure that you
or others are not injured in the process.
! Do not disconnect a trailer with an
engaged overrun brake. Otherwise, your
vehicle could be damaged by the rebound-
ing of the overrun brake.
X Make sure that the transmission is in posi-
tion P.
X Engage the electric parking brake. 184
Towing
atrailerDriving an d parking

X
Secure the traile ragainst rolling away.
X Remove the trailer cable and decouple the
trailer. Folding in the ball coupling
G
WARNING
Make sure that no persons or animals are in
the pivoting range of the ball coupling. Other-
wise, they could be injured.
X Fold the ball coupling back in if you are not
using the trailer tow hitch.
X Place the protective covering on the ball
coupling.
The release wheel is located behind the left-
hand side trim panel in the boot. 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. X
Press the ball coupling in the direction of
the arrow until it engages behind the
bumper.
Indicator lamp ?goes out and the mes-
sage in the multifunction display disap-
pears. Trailer power supply
! You can connect accessories with a
power rating of up to 240 W to the perma-
nent power supply and with a power rating
of up to 180 W to the power supply that is
switched on via the ignition lock.
The trailer battery may not be charged from
the power supply.
X To switch the connected power supply
on or off: turn the key in the ignition lock
to position 2or 0respectively.
When it leaves the factory, your vehicle's
trailer socket is equipped with a permanent
power supply and a power supply that is
switched on via the ignition lock.
The permanent power supply is supplied via
trailer socket pin 9.
The power supply that is switched on via the
ignition lock is supplied via trailer socket pin
10. Towing
atrailer
185Driving an d parking Z

The trailer's permanen
tpower supply is
switched off in the event of low vehicle supply
voltage and after six hours at the latest.
You can find more information about instal-
ling the trailer electric sataqualified special-
ist workshop. Bulb failure indicator for LED lamps
i If LED lamps are fitted in the trailer, an
error message may appear in the multi-
function display even if there is no fault. The
reason for the error message could be that
the curren thas falle nbelow the minimum
of 50 mA.
To ensure reliable operation of the bulb failure
indicator, each LED chain in the trailer lighting
must be guaranteed a minimum current of
50 mA. Trailer with 7-pin connector
General notes If your trailer has a 7-pin connector, you can
connect it to the 13-pin socket on the ball
coupling using an adapter or, if necessary, an
adapter cable. Both can be obtained in a
qualified specialist workshop.
Fitting the adapter
!
Make sure that there is sufficien tcable
play so that the cable canno tbecome
detached when cornering. X
Open the socket cover.
X Insert the connector with lug :into
groove ;on the socket and turn the con-
nector clockwise to the stop.
X Let the cover engage.
X If you are using an adapter cable, secure
the cable to the trailer with cable ties. 186
Towing
atrailerDriving an d parking

Display messages Possible causes/consequences and
M Solutions
The red
!indicato rlamp flashes and the yellow !warning
lamp is lit.
The electric parking brake is malfunctioning.
To release:
X Switch off the ignition and turn it back on.
X Release the electric parking brake manually.
To apply:
X Switch off the ignition and turn it back on.
X Engage the electric parking brake manually.
If the red !indicator lamp continues to flash:
X Do not drive on.
X Secure the vehicle against rolling away ( Ypage 299).
X Vehicles with manual transmission: engage first gear.
X Vehicles with automatic transmission: shiftthe transmission
to P.
X Turn the front wheels towards the kerb.
X Consult a qualified specialist workshop. The yellow
!warning lamp lights up. The red !indicator
lamp flashes for about ten seconds after the electric parking brake
has been applied or released. It then goes out or remains lit.
The electric parking brake is malfunctioning.
X Switch off the ignition and turn it back on.
X Engage the electric parking brake.
If it is not possible to apply the electric parking brake:
X Vehicles with manual transmission: engage first gear.
X Vehicles with automatic transmission: shift the transmission
to P.
X Visit a qualified specialist workshop.
If it is not possible to release the electric parking brake:
X Vehicles with manual transmission: release the electric park-
ing brake using the automatic emergency release
(Y page 145).
X Vehicles with automatic transmission: release the electric
parking brake automatically (Y page 145).
If the electric parking brake can still not be released:
X Consult a qualified specialist workshop. 210
Display messagesOn-board computer and displays

Display messages Possible causes/consequences and
M Solutions
The yellow
!warning lamp lights up. If you manually apply or
release the electric parkin gbrake, the red !indicator lamp
flashes.
The electric parking brake is malfunctioning. It is not possible to
apply the electric parking brake manually.
X Vehicles with manual transmission: switch off the ignition.
The electric parking brake is applied automatically.
You can release the electric parking brake using the automatic
emergency release (Y page 145).
X Vehicles with automatic transmission: shift the transmission
to Pas the electric parking brake is not applied automatically.
X Visi taqualified specialist workshop.
i If you do not wish the electric parking brake to be applied,
leave the ignition switched on, e.g. when washing the vehicle in
an automatic car wash or when having the vehicle towed. Excep-
tion :when having the vehicle towed with the front axle raised
(Y page 284). !
Pkg brake inopera‐
tive The yellow
!warning lamp lights up. The red !indicator
lamp flashes for about ten seconds after the electric parking brake
has been applied or released. It then goes out or remains lit.
The electric parking brake is malfunctioning, e.g. because of over-
voltage or undervoltage.
X Remove the cause for the overvoltage or undervoltage, e.g. by
charging the battery or restarting the engine.
X Apply or release the electric parking brake.
If it remains impossible to apply or release the electric parking
brake:
X Switch off the ignition and turn it back on.
X Apply or release the electric parking brake.
If the electric parking brake can still not be released:
X Consult a qualified specialist workshop. The display message is only shown while the vehicle is in motion.
The red
!indicator lamp flashes and the yellow !warning
lamp is lit.
It is not possible to apply the electric parking brake manually.
X Vehicles with manual transmission: engage first gear.
X Vehicles with automatic transmission: shift the transmission
to P.
X Visit a qualified specialist workshop. Display messages
211On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions
b
Reversing light The reversing lamp is faulty.
X
Chec kwhether you are permitted to replace the bulb yourself
(Y page 103).
or
X Visit a qualified specialist workshop. b
Left tail lamp
or
Right tail lamp The left or right-hand tail lamp is faulty.
X
Check whether you are permitted to replace the bulb yourself
(Y page 103).
or
X Visit a qualified specialist workshop. b
Left daytime driv‐
ing lamp
or
Right daytime driving lamp The left or right-hand daytime driving lamp is defective.
X
Check whether you are permitted to replace the bulb yourself
(Y page 103).
or
X Visit a qualified specialist workshop. b
Intell. Light Sys‐
tem inoperative The Intelligent Light System is faulty. The lights remain available
without the Intelligent Light System.
X
Visit a qualified specialist workshop. b
Malfunction See
Owner's Manual The exterior lighting is faulty.
X
Visit a qualified specialist workshop. b
Malfunction See
Owner's Manual The exterior lighting is faulty.
X
Visit a qualified specialist workshop. Vehicles with trailer tow hitch: a fuse may have blown.
X
Check the fuses (Y page 287).
X If necessary, replace the blown fuse. Observe the warning notes
as you do so.
If the display message continues to be displayed:
X Visit a qualified specialist workshop. b
AUTO
lights inoper‐
ative The light sensor is faulty.
X
Visit a qualified specialist workshop. 218
Display messagesOn-board computer and displays

Display messages Possible causes/consequences and
M Solutions
Blind Spot Assist
currently unavail‐
able See Owner's
Manual Blind Spot Assis
tis temporarily inoperative. Possible causes:
R you have established the electrical connection between the
trailer and your vehicle.
R the sensors are dirty.
R 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 9indicator lamps also light up in the exterior mir-
rors.
X When towing a trailer, confirm the display message with a.
If you are driving without a trailer and the displaym essage does
not disappear:
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Engage the electric parking brake.
X Clean the sensors (Y page 270).
X Restart the engine.
If the system detects that the sensors are fully operational, the
display message disappears.
Blind Spot Assist is operational again. Blind Spot Assist
inoperative Blind Spot Assist is faulty.
The yellow
9indicator lamps also light up in the exterior mir-
rors.
X Visit a qualified specialist workshop. Park Assist
cancelled 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 have inadvertently touched the multifunction steering wheel
while steering intervention was active.
X
While steering intervention is active, make sure that the multi-
function steering wheel is not touched. The vehicle has started to skid and ESP
®
has intervened.
X Use Active Parking Assist again later (Y page 166).224
Display messagesOn-board computer and displays