trailer MERCEDES-BENZ CLA 2013 Owner's Guide

XPress 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.
XTo switch the connected power supply
on or off: turn the key in the ignition lock
to position 2 or 0 respectively.
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 instal-
ling the trailer electrics at a qualified 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 current has fallen below 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
Trailers with 7-pin connector: you can
make a connection to the 13-pin connector
on the ball coupling using an adapter plug or,
if necessary, an adapter cable. Both can be
obtained in 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.
XOpen the socket cover.XInsert connector with lug : into
groove ; of the socket. Turn the connec-
tor clockwise to the stop.XLet the cover engage.XIf you are using an adapter cable, secure
the cable to the trailer with cable ties.206Towing a trailerDriving and parking

Safety systemsDisplay messagesPossible causes/consequences and M Solutions!÷
currently unavail‐
able See Owner's
ManualABS (Anti-lock Braking System), ESP ®
(Electronic Stability Pro-
gram), BAS (Brake Assist), PRE-SAFE ®
, the HOLD function, hill
start assist and ESP ®
trailer stabilisation are temporarily unavail-
able.
The adaptive brake lights and COLLISION PREVENTION ASSIST/
COLLISION PREVENTION ASSIST PLUS may also have failed.
In addition, the ÷, å and ! warning lamps 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.GWARNING
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.
XCarefully 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:
XDrive on carefully.XVisit a qualified specialist workshop.!÷
inoperative See
Owner's ManualABS, ESP ®
, BAS, PRE-SAFE ®
, the HOLD function, hill start assist
and ESP ®
trailer stabilisation are unavailable due to a malfunction.
The adaptive brake lights and COLLISION PREVENTION ASSIST/
COLLISION PREVENTION ASSIST PLUS may also have failed.
In addition, the J, ÷ , å and ! warning lamps light
up in the instrument cluster.
ATTENTION ASSIST is deactivated.GWARNINGDisplay messages227On-board computer and displaysZ

Display messagesPossible causes/consequences and M SolutionsThe 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.XDrive on carefully.XVisit a qualified specialist workshop immediately.÷
currently unavail‐
able See Owner's
ManualESP ®
, BAS, PRE-SAFE ®
, the HOLD function, hill start assist and
ESP ®
trailer stabilisation are temporarily unavailable.
The adaptive brake lights and COLLISION PREVENTION ASSIST/
COLLISION PREVENTION ASSIST PLUS may also have failed.
In addition, the ÷ and å warning lamps light up in the
instrument cluster.
ATTENTION ASSIST is deactivated.
The self-diagnosis function, for example, may not be complete.GWARNING
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.
XCarefully 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:
XDrive on carefully.XVisit a qualified specialist workshop.228Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M Solutions÷
inoperative See
Owner's ManualESP ®
, BAS, PRE-SAFE ®
, the HOLD function, hill start assist and
ESP ®
trailer stabilisation are not available due to a malfunction.
The adaptive brake lights and COLLISION PREVENTION ASSIST/
COLLISION PREVENTION ASSIST PLUS may also have failed.
In addition, the ÷ and å warning lamps light up in the
instrument cluster.
ATTENTION ASSIST is deactivated.GWARNING
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.
XDrive on carefully.XVisit a qualified specialist workshop.T !
÷
inoperative See
Owner's ManualEBD (electronic brake force distribution), ABS, ESP ®
, BAS, PRE-
SAFE ®
, the HOLD function, hill start assist and ESP ®
trailer stabi-
lisation are unavailable due to a malfunction.
The adaptive brake lights and COLLISION PREVENTION ASSIST/
COLLISION PREVENTION ASSIST PLUS may also have failed.
In addition, the ÷, å and ! warning lamps light up in
the instrument cluster and a warning tone sounds.
ATTENTION ASSIST is deactivated.GWARNING
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.
XDrive on carefully.XVisit a qualified specialist workshop immediately.Display messages229On-board computer and displaysZ

Display messagesPossible causes/consequences and M Solutionsb
Trailer Left-hand
tail lamp orTrailer
Right-hand tail
lampThe left or right-hand trailer tail lamp is faulty.XObserve the separate operating instructions provided by the
trailer manufacturer.b
Trailer left indi‐
cator  or Trailer
right indicatorThe left or right-hand trailer turn signal lamp is faulty.XObserve the separate operating instructions provided by the
trailer manufacturer.b
Trailer brake lampThe trailer brake lamp is faulty.XObserve the separate operating instructions provided by the
trailer manufacturer.b
Rear left indica‐
tor  or  Rear right
indicatorThe rear left-hand or rear right-hand turn signal is faulty.XCheck whether you are permitted to replace the bulb yourself
( Y page 114).
or
XVisit a qualified specialist workshop.b
Front left indica‐
tor  or  Front right
indicatorThe front left-hand or front right-hand turn signal is faulty.XCheck whether you are permitted to replace the bulb yourself
( Y page 114).
or
XVisit a qualified specialist workshop.b
Left mirror indica‐
tor  or  Right mir‐
ror indicatorThe turn signal in the left-hand or right-hand exterior mirror is
faulty.XCheck whether you are permitted to replace the bulb yourself
( Y page 114).
or
XVisit a qualified specialist workshop.b
3rd brake lampThe third brake lamp is faulty.XCheck whether you are permitted to replace the bulb yourself
( Y page 114).
or
XVisit a qualified specialist workshop.Display messages237On-board computer and displaysZ

Display messagesPossible causes/consequences and M Solutionsb
Reversing lightThe reversing lamp is faulty.XCheck whether you are permitted to replace the bulb yourself
( Y page 114).
or
XVisit a qualified specialist workshop.b
Left tail lamp  or 
Right tail lamp The left or right-hand tail lamp is faulty.XCheck whether you are permitted to replace the bulb yourself
( Y page 114).
or
XVisit a qualified specialist workshop.b
Left daytime driv‐
ing lamp  or Right
daytime driving
lampThe left-hand or right-hand daytime driving lamp is faulty.XCheck whether you are permitted to replace the bulb yourself
( Y page 114).
or
XVisit a qualified specialist workshop.b
Intell. Light Sys‐
tem inoperativeThe Intelligent Light System is faulty. The lights remain available
without the Intelligent Light System.XVisit a qualified specialist workshop.b
Malfunction See
Owner's ManualThe exterior lighting is faulty.XVisit a qualified specialist workshop.Vehicles with trailer tow hitch: a fuse may have blown.XCheck the fuses ( Y page 312).XIf necessary, replace the blown fuse. Observe the warning notes
as you do so.
If the display message continues to be displayed:
XVisit a qualified specialist workshop.b
AUTO lights inoper‐
ativeThe light sensor is faulty.XVisit a qualified specialist workshop.b
Switch off lightsThe lights are still switched on when you leave the vehicle. A
warning tone also sounds.XTurn the light switch to Ã.Display messages239On-board computer and displaysZ

Display messagesPossible causes/consequences and M SolutionsLane Keeping
Assist currently
unavailable See
Owner's ManualLane Keeping Assist is deactivated and temporarily inoperative.
Possible causes:
R the windscreen is dirty in the camera's field of vision.
R visibility is impaired due to heavy rain, snow or fog.
R there are no lane markings for a longer period.
R the lane markings are worn, dark or covered, e.g. by dirt or snow.
Once the causes listed above no longer apply, the display message
goes out.
Lane Keeping Assist is operational again.
If the display message does not disappear:XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.XSecure the vehicle against rolling away ( Y page 162).XClean the windscreen.Lane Keeping
Assist inoperativeLane Keeping Assist is faulty.XVisit a qualified specialist workshop.Blind Spot Assist
currently unavail‐
able See Owner's
ManualBlind Spot Assist is temporarily inoperative.
You have established the electrical connection between the trailer
and your vehicle.XPress a on the steering wheel to confirm the display mes-
sage.
Blind Spot Assist is deactivated while towing a trailer.
244Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M Solutionsj
Check trailer
hitch lockThe trailer tow hitch is not correctly engaged.
A warning tone also sounds.XStop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.XApply the electric parking brake.XEngage 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 ManualThe power steering assistance is faulty.
A warning tone also sounds.GWARNING
You will need to use more force to steer.
There is a risk of an accident.
XCheck whether you are able to apply the extra force required.XIf you are able to steer safely: carefully drive on to a qualified
specialist workshop.XIf you are unable to steer safely: do not drive on. Contact the
nearest qualified specialist workshop.&
inoperative Bat‐
tery lowYou 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.XLet 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 136).XDrive 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
vehicleThere is too little fuel in the fuel tank. The auxiliary heating cannot
be switched on ( Y page 136).XRefuel at the nearest filling station.Display messages253On-board computer and displaysZ

Safety systemsProblemPossible causes/consequences and M SolutionsJ
The red brake system
warning lamp is lit while
the engine is running. A
warning tone also
sounds.There is insufficient brake fluid in the brake fluid reservoir.GWARNING
The braking efficiency may be impaired.
There is a risk of an accident.
XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions. Do not continue driving
under any circumstances.XSecure the vehicle against rolling away ( Y page 162).XDo not top up the brake fluid. Topping up will not rectify the
fault.XConsult a qualified specialist workshop.XObserve the additional display messages in the multifunction
display.!
The yellow ABS warning
lamp is lit while the
engine is running.ABS (Anti-lock Brake System) has been deactivated due to a fault.
Therefore, BAS (Brake Assist), COLLISION PREVENTION ASSIST,
COLLISION PREVENTION ASSIST PLUS, ESP ®
(Electronic Stability
Program), PRE-SAFE ®
, the HOLD function, hill start assist, the
adaptive brake lights and ESP ®
trailer stabilisation, for example,
are also deactivated.
ATTENTION ASSIST is deactivated.GWARNING
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.
XObserve the additional display messages in the multifunction
display.XDrive on carefully.XVisit a qualified specialist workshop.
If the ABS control unit is faulty, there is also a possibility that other
systems, such as the navigation system or the automatic trans-
mission, will be unavailable.
256Warning and indicator lamps in the instrument clusterOn-board computer and displays

ProblemPossible causes/consequences and M Solutions!
The yellow ABS warning
lamp is lit while the
engine is running.ABS is temporarily unavailable. Therefore, BAS, COLLISION PRE-
VENTION ASSIST, COLLISION PREVENTION ASSIST PLUS, ESP ®
,
EBD (electronic brake force distribution), PRE-SAFE ®
, the HOLD
function, hill start assist, the adaptive brake lights and ESP ®
trailer
stabilisation, for example, are also deactivated.
Possible causes:
R self-diagnosis is not yet complete.
R the on-board voltage may be insufficient.
ATTENTION ASSIST is deactivated.GWARNING
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 a risk of an accident.
XCarefully drive on a suitable stretch of road, making slight steer-
ing movements at a speed above 20 km/h.
The functions mentioned above are available again when the
warning lamp goes out.
If the warning lamp is still on:
XObserve the additional display messages in the multifunction
display.XDrive on carefully.XVisit a qualified specialist workshop.Warning and indicator lamps in the instrument cluster257On-board computer and displaysZ