
XSlide boltAinto the hole in the ball coupling
recess and the ball coupling to the stop.
XSecure the bolt using spring cotter B.
XCheck the ball coupling, bolt and spring cotter
for correct installation.
If the ball coupling cannot be correctly mounted,
remove the ball coupling. Under these circum-
stances, the ball coupling must not be used for
trailer towing.
Have the entire trailer tow hitch checked at a
qualified specialist workshop.
Coupling up a trailer
!
Do not connect the trailer's brake system (if
featured) to the hydraulic brake system of the
towing vehicle, as the latter is equipped with
an anti-lock brake system. Doing so will result
in a loss of function of the brake systems of
both the vehicle and the trailer.
XShift the transmission to position P.
XApply the vehicle's electric parking brake.
XStart the engine.
XVehicles with AIRMATIC package: select
normal level and the Comfortdrive program.
XSwitch off the engine.
XClose the doors and tailgate.
XCouple up the trailer.
XEstablish the electrical connection between
the vehicle and the trailer.
XCheck that the trailer lighting system is work-
ing.
XPush the combination switch upwards/down-
wards and check whether the corresponding
turn signal on the trailer flashes.
A trailer that is connected is recognized only
when the electrical connection is established
correctly and when the lighting system is work-
ing properly. The function of other systems also
depends on this, for example:
RESP®
RParking Assist PARKTRONIC
RParking Pilot
RActive Blind Spot Assist
RActive Lane Keeping Assist
iVehicles with the AIRMATIC package: if you
couple up a trailer, the vehicle always remains
at normal level. When coupling up a trailer,
please observe the foll
owing:
RIf the normal level has not been set man-
ually, the vehicle is automatically lowered
to normal level. This is the case if a speed of
5 mph (8 km/h) is reached.
RThe
Sport drive program is not available.
These restrictions apply to all accessories
powered through a connection to the trailer
power socket of your vehicle, e.g. a bicycle
carrier.
Observe the maximum permissible trailer
dimensions (width and length).
222Towing a trailer
Driving and parking 

Most U.S. states and all Canadian provinces
require by law:
RSafety chains between the towing vehicle and
the trailer. The chains should be cross-wound
under the trailer drawbar. They must be fas-
tened to the vehicle's trailer coupling, not to
the bumper or the axle.
Leave enough play in the chains to make tight
cornering possible.
RA separate brake system for certain types of
trailer.
RSafety switch for braked trailers. Check the
specific legal requirements applicable to your
state.
If the trailer becomes detached from the tow-
ing vehicle, the safety feature triggers the
trailer brakes.
Towing a trailer
There are numerous legal requirements con-
cerning the towing of a trailer, e.g. speed restric-
tions. Make sure that your car/trailer combina-tion complies with the local regulations:
Rin your place of residence
Rin the location to which you are driving
The police and local authorities can provide reli-
able information.
Observe the following when towing a trailer:
RTo gain driving experience and to become
accustomed to the new handling characteris-
tics, you should practice the following in a
traffic-free location:
-cornering
-stopping
-backing up
RBefore driving, check:
-trailer tow hitch
-safety switch for braked trailers
-safety chains
-electrical connections
-lights
-wheels
RAdjust the exterior mirrors to provide an
unobstructed view of the rear section of the
trailer.
RIf the trailer has electronically controlled
brakes, pull away carefully. Brake manually using the brake controller and check whether
the brakes function correctly.
RSecure any objects on the trailer to prevent
the cargo from slipping when the vehicle is in
motion.
RWhen you couple up a trailer, check at regular
intervals that the load is firmly secured. If the
trailer is equipped with trailer lights and
brakes, check the trailer to ensure that these
are working.
RBear in mind that the handling will be less
stable when towing a trailer than when driving
without one. Avoid sudden steering move-
ments.
RThe vehicle/trailer combination is heavier,
accelerates more slowly, has a decreased
gradient climbing capability and a longer
braking distance.
It is more susceptible to side winds and
requires more careful steering.
RIf possible, do not brake suddenly, but instead
depress the brake pedal moderately at first so
that the trailer can activate its brakes. Then
increase the pressure on the brake pedal.
RIf the automatic transmission repeatedly
shifts between gears on uphill or downhill gra-
dients, shift to a lower gear using the left-hand
steering wheel paddle shifter.
A lower gear and lower speed reduce the risk
of engine failure.
RWhen driving downhill, shift to a lower gear to
utilize the engine's braking effect.
Avoid continuous brake application as this
may overheat the vehicle brakes and, if instal-
led, the trailer brakes.
RIf the coolant temperature increases dramat-
ically while the air-condit ioning system is
switched on, switch off the air-conditioning
system.
Coolant heat can also be dissipated by open-
ing the windows and switching the ventilation blower and the interior temperature to the
highest level.
RWhen overtaking, pay particular attention to
the extended length of your vehicle/trailer
combination.
Due to the length of the vehicle/trailer com-
bination, you require additional road space in
relation to the vehicle you are overtaking
before you can change back to the original
lane.
Towing a trailer223
Driving and parking
Z 

Safety systems
Display messagesPossible causes/consequences andMSolutions
!÷
Currently Unavaila‐ble See Operator'sManual
ABS (Anti-lock Braking System) and ESP®(Electronic Stability Pro-
gram) are temporarily not available.
Other driving systems and driving safety systems may also malfunc-
tion.
In addition, the ÷,åand! warning lamps light up in the
instrument cluster.
Possible causes are:
Rself-diagnosis is not yet complete
Rthe 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 affected.
The braking distance in an emergency braking situation can increase.
If ESP
®is not operational, ESP®is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
XCarefully drive a suitable distance, making slight steering move-
ments at a speed above 12 mph (20 km/h).
If the display message disappears, the functions mentioned above are available again.
If the multifunction display still shows the display message:
XDrive on carefully.
XVisit a qualified specialist workshop immediately.
!÷
Inoperative SeeOperator's Manual
ABS and ESP®are malfunctioning.
Other driving systems and driving safety systems may also malfunc-
tion.
The $ (USA only) or J(Canada only), ÷,åand!
warning lamps in the instrument cluster also light up.
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 affected.
The braking distance in an emergency braking situation can increase.
If ESP
®is not operational, ESP®is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
XDrive on carefully.
XVisit a qualified specialist workshop immediately.
244Display messages
On-board computer and displays 

Display messagesPossible causes/consequences andMSolutions
÷
Currently Unavaila‐ble See Operator'sManual
ESP®is temporarily unavailable .
Other drivin gsystems and drivin gsafet ysystems may also malfunc -
tion .
In addition ,th e÷ andå warning lamp sligh tup in th einstru-
men tcluster.
The self-diagnosis function might no tbe complete, for example.
ATTENTION ASSIST is deactivated.
GWARNIN G
The brak esystem continues to function normally, but without th e
function slisted above. The wheels could therefor eloc kif you brak e
hard, for example.
The braking distanc ein an emergenc ybraking situation can thus
increase.
If ES P
®is no toperational, ES P®is unable to stabiliz eth evehicle.
There is an increased ris kof skiddin gand an accident.
XCarefully drive asuitable distance, making slight steering move-
ments at aspeed abov e12 mph (20 km/ h).
If the display message disappears, the functions mentioned above are available again.
If the multifunction display still shows the display message:
XDrive on carefully.
XVisit a qualified specialist workshop immediately.
÷
Inoperative SeeOperator's Manual
ESP®is malfunctioning.
Other driving systems and driving safety systems may also malfunc-
tion.
In addition, the ÷andå warning lamps light up in the instru-
ment cluster.
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 braking distance in an emergency braking situation can thus
increase.
If ESP
®is not operational, ESP®is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
XDrive on carefully.
XVisit a qualified specialist workshop immediately.
Display messages245
On-board computer and displays
Z 

Display messagesPossible causes/consequences andMSolutions
T!
÷
Inoperative SeeOperator' sManual
EB D(electronic brak eforce distribution), AB Sand ES P®are malfunc -
tioning .
Other drivin gsystems and drivin gsafet ysystems may also malfunc -
tion .
In addition ,th e÷, åand! warning lamp sligh tup in th e
instrumen tcluste rand awarning tone sounds.
GWARNIN G
The brak esystem continues to function normally, but without th e
function slisted above. The wheels could therefor eloc kif you brak e
hard, for example.
The steerabilit yand braking characteristics may be severely affected.
The braking distanc ein an emergenc ybraking situation can increase.
If ES P
®is no toperational, ES P®is unable to stabiliz eth evehicle.
There is an increased ris kof skiddin gand an accident.
XDrive on carefully.
XVisit aqualified specialist workshop immediately.
F(US A
only)
!(Canada
only)
Tur nOn the Igni‐
tio ntoReleas etheParkingBrake
The red F(USAonly) or !(Canada only) indicator lamp lights
up.
You attempte dto release th eelectric parking brak ewhile th eignition
was switched off .
XSmartKey:insert th eSmartKey int oth eignition loc kand tur nto
position 1.
XKEYLESS-GO: switch on theignition .
F(USA
only)
!(Canada
only)
Please
Releas ePark‐ing Brake
The red F(USAonly) or !(Canada only) indicator lamp flashes
and awarning tone sounds. Acondition for automatic release of th e
electric parking brak eis no tfulfilled (
Ypage 157).
You are drivin gwit hth eelectric parking brak eapplied.
XReleas eth eelectric parking brak emanually.
The red F(USAonly) or !(Canada only) indicator lamp flashes
and awarning tone sounds.
You are usin gth eelectric parking brak efor emergenc ybraking
(
Ypage 157).
F(US A
only)
!(Canada
only)
Parkin gBrake See
Operator' sManual
The yellow !warning lamp lights up.
The electric parking brak eis malfunctioning .
To apply :
XSwitchth eignition off .
XPress theelectric parking brak ehandle for at least te nseconds.
XShift th etransmission to position j.
XConsult aqualified specialist workshop .
246Display messages
On-board computer and displays 

Display messagesPossible causes/consequences andMSolutions
The yellow!warning lamp lights up. The red F(USAonly)
or ! (Canada only) indicator lamp flashes for about te nseconds
after th eelectric parking brak ehas been applie dor released. It then
goe sout or remain slit .
The electric parking brak eis malfunctioning .
XSwitchoff th eignition and tur nit bac kon .
XApply th eelectric parking brake.
If it is no tpossibl eto engage th eelectric parking brake:
XShift th etransmission to position j.
XVisitaqualified specialist workshop .
If it is no tpossibl eto release th eelectric parking brake:
XReleas eth eelectric parking brak eautomatically (Ypage 157).
If th eelectric parking brak estill canno tbe released:
XConsult aqualified specialist workshop .
The yellow!warning lamp lights up. If you manually apply or
release th eelectric parking brake, th ered F (USAonly) or !
(Canada only) indicator lamp flashes .
The electric parking brak eis malfunctioning .It is no tpossibl eto apply
th eelectric parking brak emanually.
XShift th etransmission to position j.
XVisit aqualified specialist workshop .
F(USA
only)
!(Canada
only)
Parkin gBrake Inop‐
erativ e
The yellow !warning lamp lights up. The red F(USAonly)
or ! (Canada only) indicator lamp flashes for about te nseconds
after th eelectric parking brak ehas been applie dor released. It then
goe sout or remain slit .
The electric parking brak eis malfunctioning ,e.g. because of over-
voltag eor undervoltage.
XRemove th ecaus efor th eovervoltage or undervoltage, e.g. by
charging th ebattery or restarting th eengine.
XEngage or release th eelectric parking brake.
If it remain simpossible to apply or release th eelectric parking brake:
XSwitc hoff th eignition and tur nit bac kon .
XEngage or release th eelectric parking brake.
If th eelectric parking brak estill canno tbe released:
XConsult aqualified specialist workshop .
If th eelectric parking brak estill canno tbe applied:
XVisit aqualified specialist workshop .
248Display messages
On-board computer and displays 

Display messagesPossible causes/consequences andMSolutions
The yellow!warning lamp lights up and th ered F (USAonly)
or ! (Canada only) indicator lamp flashes .
It is no tpossibl eto apply th eelectric parking brak emanually.
XShift th etransmission to position j.
XVisit aqualified specialist workshop .
$(USAonly)
J(Canada only)
Check Brake Fluid
Level
There is no tenough brak efluid in th ebrak efluid reservoir .In addition ,
th e$ (USAonly) or J(Canada only) warning lamp lights up in
th einstrumen tcluste rand awarning tone sounds.
GWARNIN G
The braking effec tmay be impaired.
There is aris kof an accident.
XPull ove rand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions. Do no tcontinu edrivin g
under any circumstances.
XSecur eth evehicl eagainst rollin gaway (Ypage 156).
XConsult aqualified specialist workshop .
XDo notadd brak efluid .This does no tcorrec tth emalfunction .
#
CheckBrakePadWear
The brak epads/linings hav ereached their wear limit.
US Aonly: th e$ red brak esystem warning lamp is lit while th e
engin eis running.
XVisit aqualified specialist workshop .
G
Inoperative
Oneor mor emain features of th embrace system are malfunctioning .
XVisitaqualified specialist workshop .
ActiveBrakeAssistFunctionsCurrentlyLimitedSee Opera‐tor's Manual
Active Brake Assis twit hcross-traffic function is temporarily inopera-
tive.
Possibl ecauses are:
RThe radar sensor system is temporarily inoperative, e.g. due to
electromagneti cradiation emitted by nearby TV or radi ostation sor
other source sof electromagneti cradiation .
RThe system is outside th eoperating temperature range.
RThe on-boar dvoltag eis to olow.
Whe nth ecauses state dabov eno longer apply, th edisplay message
disappears.
Active Brake Assis twit hcross-traffic function or PRE ‑S AF E
®PLU Sis
functional again .
If th edisplay message does no tdisappear :
XPull overand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 156).
XRestart th eengine.
Display messages24 9
On-board computer and displays
Z 

Display messagesPossible causes/consequences andMSolutions
RadarSensorsDirtySee Operator' sMan ‐ual
The radar sensor system is malfunctioning .
Possibl ecauses are:
Rdir ton sensor s
Rheavyrain or snow
Rwhen drivin gon inter-urban roads without traffic or infrastructure,
e.g. in desert-like area s
At least on edrivin gsystem or drivin gsafet ysystem is malfunctioning
or is temporarily unavailable :
RPRE-SAFE®PLUS
RActive Brake Assis t
RActive LaneKeepin gAssis t
RActive Blind Spot Assis t
RDistancePilo tDISTRONI C
If th eradar sensor system in fron tis dirty, Active Blind Spot Assis twill
no tperfor m acourse-correcting brak eapplication .
A warning tone also sounds.
Once th ecaus eof th eproblem is no longer present, th edrivin gand
drive safet ysystems will be available again .The display message dis-
appears.
If th edisplay message does no tdisappear :
XPull overand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 156).
XSwitchoff th eengine.
XClean all sensor s (Ypage 330).
XRestart theengine.
The display message disappears.
6
SRSMalfunctionSer ‐viceRequired
The restrain tsystem is malfunctioning .
The 6 warning lamp also lights up in th einstrumen tcluster.
GWARNIN G
The air bags or Emergency Tensioning Devices may either be triggered
unintentionally or, in th eevent of an accident, may no tbe triggered .
There is an increased ris kof injury.
XVisit aqualified specialist workshop immediately.
Fo rfurther information about th erestrain tsystem, see (
Ypage 44).
6
Front Lef tMalfunc‐tio nServic eRequiredorFrontLef tMalfunctionServic eRequired
The restrain tsystem has malfunctioned at th efron ton th elef tor right .
The 6 warning lamp also lights up in th einstrumen tcluster.
GWARNIN G
The air bags or Emergency Tensioning Devices may either be triggered
unintentionally or, in th eevent of an accident, may no tbe triggered .
There is an increased ris kof injury.
XVisit aqualified specialist workshop immediately.
Display messages25 1
On-board computer and displays
Z