2014 MERCEDES-BENZ B-CLASS HATCHBACK trailer

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. See 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 175).
This also applies if you have activated cruise
control, SPEEDTRONIC or DISTRONIC 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.
Briefly depressing the accelerator pedal on
downhill gradients while the manual drive
program Mis temporarily activated (vehicles
with automatic transmission): the automatic
transmission may switch back to the last
active automatic drive program Eor 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 to the vehicle 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 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. 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. 226
Towing a trailerDriving and parking

X
To open the cover: turn handle:anti-
clockwise, the fold down and remove
cover ;. 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.
The indicator lamp on the release wheel
goes out. The power socket folds down
automatically.
The multifunction display shows the
Check Check trailer
trailer hitch
hitchlock
lockdisplay 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 horizontally 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 connected trailer is only recognised when
the electrical connection is established
correctly and when the lighting system is
working properly. The function of other sys-
tems, such as ESP ®
or PARKTRONIC 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 between
the vehicle and the trailer drawbar. This poses a risk of injury.
Do not uncouple a trailer with an engaged
overrun brake. Towing a trailer
227Driving and parking Z

!
Do not disconnect a trailer with an
engaged overrun brake. Otherwise, your
vehicle could be damaged by the rebound- ing of the overrun brake.
! Remove the installed adapter cable
before folding in the ball coupling. Other-
wise, damage may occur to the rear
bumper and the adapter cable.
X Make sure that the transmission is in posi-
tion P.
X Apply the electric parking brake.
X Secure the trailer against rolling away.
X Remove the trailer cable and decouple the
trailer. Folding in 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.
Fold the ball coupling back in if you are not
using the trailer tow hitch.
The release wheel is located behind the left-
hand side trim panel in the boot.
X Place the protective covering on the ball
coupling. X
To open the cover: turn handle:anti-
clockwise, then fold down and remove
cover ;. X
Pull out release wheel =.
X Turn release wheel =anti-clockwise as far
as it will go.
The ball coupling disengages and folds in
behind the rear bumper. Indicator lamp ?
flashes. X
Press the ball coupling in the direction of
the arrow until it engages behind the
bumper.
The indicator lamp on the release knob and
the message in the multifunction display go
out. 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. 228
Towing a trailerDriving and parking

The trailer battery may not be charged from
the power supply.
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.
The trailer's permanent power 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 fitting
the trailer electrics at a qualified specialist
workshop.
X To switch the connected power supply
on or off: turn the key to position 2or 0
respectively (Y page 159). Failure check for LEDs
If LED lamps are fitted in the trailer, a mal-
function message may appear in the multi-
function display even if there is no fault. The
reason for the error message may be that the
current has fallen below the minimum of
50 mA.
To ensure reliable operation of the 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 Trailer with 7-pin connector:
you can con-
nect to the 13-pin socket on the ball coupling
using an adapter or, if necessary, an adapter
cable. Both can be obtained at a qualified
specialist workshop. Fitting the adapter !
Make sure that there is sufficient cable
play so that the cable cannot become
detached when cornering.
! Remove the installed adapter cable
before folding in the ball coupling. Other-
wise, damage may occur to the rear
bumper and the adapter cable. X
Open the socket cover.
X Insert the plug connector with lug :into
groove =on the socket.
X Turn bayonet connection ;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. Towing a trailer
229Driving and parking Z

Safety systems
Display messages
Possible causes/consequences and
M
MSolutions !÷
currently unavail‐ currently unavail‐
able See Owner's able See Owner's
Manual Manual ABS (Anti-lock Braking System), BAS (Brake Assist System), ESP
®
(Electronic Stability Program), ESP ®
trailer stabilisation, the HOLD
function, hill start assist and PRE-SAFE ®
are temporarily unavail-
able.
The adaptive brake lights and COLLISION PREVENTION ASSIST
PLUS may also have failed.
In addition, the !,÷andå warning lamps may light up
in the instrument cluster.
ATTENTION ASSIST is deactivated.
Possible causes:
R self-diagnosis is not yet complete.
R the on-board voltage may be insufficient
G WARNING
The brake system continues to function normally, but without the functions listed above. The wheels could therefore lock if you
brake hard, for example.
The steerability and braking characteristics may be severely affec-ted. The braking distance may increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Carefully drive on a suitable stretch of road, making slight steer-
ing movements, at a speed above 20 km/h.
If the display message disappears, the functions mentioned
above are available again.
If the display message continues to be displayed:
X Drive on carefully.
X Visit a qualified specialist workshop. !÷
inoperative See inoperative See
Owner's Manual Owner's Manual ABS, BAS, ESP
®
, ESP ®
trailer stabilisation, the HOLD function, hill
start assist and PRE-SAFE ®
are not available due to a malfunction.
The adaptive brake lights and COLLISION PREVENTION ASSIST
PLUS may also have failed.
The !, ÷, åandJ warning lamps may also light up
in the instrument cluster.
ATTENTION ASSIST is deactivated.
G WARNING 252
Display messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
The steerability and braking characteristics may be severely affec- ted. The braking distance may increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Drive on carefully.
X Visit a qualified specialist workshop immediately. ÷
currently unavail‐ currently unavail‐
able See Owner's able See Owner's
Manual Manual ESP
®
, ESP ®
trailer stabilisation, BAS, the HOLD function, hill start
assist and PRE-SAFE ®
are temporarily unavailable.
The adaptive brake lights and COLLISION PREVENTION ASSIST
PLUS may also have failed.
In addition, the ÷andå warning lamps may light up in the
instrument cluster.
ATTENTION ASSIST is deactivated.
The self-diagnosis function, for example, may not be complete.
G WARNING
The brake system continues to function normally, but without the functions listed above.
The braking distance may thus increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Carefully drive on a suitable stretch of road, making slight steer-
ing movements at a speed above 20 km/h.
If the display message disappears, the functions mentioned
above are available again.
If the display message continues to be displayed:
X Drive on carefully.
X Visit a qualified specialist workshop. Display
messages
253On-board computer and displays Z

Display messages
Possible causes/consequences and
M
MSolutions ÷
inoperative See inoperative See
Owner's Manual Owner's Manual ESP
®
, ESP ®
trailer stabilisation, BAS, the HOLD function, hill start
assist and PRE-SAFE ®
are not available due to a malfunction.
The adaptive brake lights and COLLISION PREVENTION ASSIST
PLUS may also have failed.
In addition, the ÷andå warning lamps may light up in the
instrument cluster.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the functions listed above.
The braking distance may thus increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Drive on carefully.
X Visit a qualified specialist workshop. T!
÷
inoperative See inoperative See
Owner's Manual Owner's Manual EBD (electronic brake force distribution), ABS, BAS, ESP
®
, ESP ®
trailer stabilisation, the HOLD function, hill start assist and PRE-
SAFE ®
are not available due to a malfunction.
The adaptive brake lights and COLLISION PREVENTION ASSIST
PLUS may also have failed.
A warning tone sounds
In addition, the ÷,åand! warning lamps may light up
in the instrument cluster.
G WARNING
The brake system continues to function normally, but without the functions listed above. The front and rear wheels could therefore
lock, for example, if you brake hard.
The steerability and braking characteristics may be severely affec-ted. The braking distance may increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Drive on carefully.
X Visit a qualified specialist workshop immediately. 254
Display
messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions front-passenger front airbag deactivation system has disa-
bled the front-passenger front airbag (Y
page 50)
R the Front-passenger airbag enabled See Owner's Front-passenger airbag enabled See Owner's
Manual
Manual orFront-passenger
Front-passenger airbag
airbagdisabled
disabled See
SeeOwn‐
Own‐
er's Manual
er's Manual display messages must not be shown in the
multifunction display.
X Wait for a period of at least 60 seconds until the necessary sys-
tem checks have been completed.
X Make sure that the display messages do not appear in the mul-
tifunction display.
If these conditions are met, the front-passenger seat can be occu-
pied again. Whether the PASSENGER AIRBAG OFF or ON indicator
lamp remains lit or goes out depends on how the automatic front-
passenger front airbag deactivation system classifies the occu-
pant.
If the conditions are not met, the system is not operating correctly.
X Visit a qualified specialist workshop immediately.
Further information on the automatic front-passenger front airbag deactivation feature (Y page 49).Lights
i Vehicles with LED light bulbs in the light clusters:
The display message for the corresponding light will only appear if all the LEDs have failed. Display messages
Possible causes/consequences and
M MSolutions b
Left dipped beam Left dipped beam
or
Right dipped Right dipped
beam
beam The left or right-hand dipped-beam headlamp is faulty.
X Halogen headlamp: replace the bulb (Ypage 128).
X LED headlamps: consult a qualified specialist workshop. b
Trailer left tail Trailer left tail
lamp lampor
Trailer
Trailer
right tail lamp
right tail lamp The left or right-hand trailer tail lamp is faulty.
X Observe the manufacturer's operating instructions. b
Trailer left turn Trailer left turn
signal signal
orTrailerTrailer
right turn signal
right turn signal The left or right-hand trailer turn signal lamp is faulty.
X Observe the manufacturer's operating instructions. Display
messages
265On-board computer and displays Z