tem and prevents the brakes from overheating
and wearing too quickly. If you need additional
braking, depress the brake pedal repeatedly
rather than continuously.
Driving tips
If the trailer swings from side to side:
XDo not accelerate.
XDo not counter-steer.
XBrake if necessary.
RMaintain a greater distance from the vehicle
in front than when driving without a trailer.
RAvoid braking abruptly. If possible, brake gen-tly at first to allow the trailer to run on. Then,
increase the braking force rapidly.
RThe values given for gradient-climbing capa-
bilities from a standstill refer to sea level.
When driving in mountainous areas, note that
the power output of the engine and, conse-
quently, the vehicle's gradient-climbing capa-
bility, decreases with increasing altitude.
Installing the ball coupling
GWARNING
If the ball coupling is not correctly installed
and secured, it can come loose during the
journey and endanger other road users. There is a risk of an accident and injury.
Always install and secure the ball coupling as
described. Before every journey, ensure that
the ball coupling is secured with the bolt and
the corresponding spring cotter.
GWARNING
If the ball coupling is not installed correctly or not secured with the bolt provided and the
corresponding spring cotter, the trailer may
come loose. There is a risk of an accident.
Always install and secure the ball coupling as
described. Before every journey, ensure that
the ball coupling is secured with the bolt and
the corresponding spring cotter.
GWARNING
If the ball coupling is not installed and secured
correctly the trailer may come loose. There is
a risk of an accident.
Install and secure the ball coupling as descri-
bed in the ball coupling installation instruc-
tions. Make sure that the ball coupling is
installed and secured correctly before every
journey.
XPull protective cap :in the direction of the
arrow, out of the ball coupling recess.
XStow protective cap :so that it cannot be
thrown around.
Observe the loading guidelines (
Ypage 329)
and the safety notes regarding stowage
spaces (
Ypage 330).
258Towing a trailer
Driving an d parking
XInsert the ball coupling horizontally into ball
coupling recess;in the direction of the
arrow until the holes in ball coupling =are in
line with the holes in ball coupling recess ?.
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.
Towing a trailer259
Driving and parking
Z
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®
RPARKTRONIC
RActive Parking Assist
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 following:
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 leng
th).
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 switch applies 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
tra
iler 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.
260Towing a trailer
Driving an d parking
RIf possible, do not brake suddenly, but insteaddepress 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 toutilize 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-conditioning 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.
Decoupling a trailer
GWARNING
If you uncouple a trailer with the overrun
brake engaged, you could trap your hand
between the vehicle and the trailer drawbar.
There is a risk of injury.
Do not uncouple a trailer if the overrun brake
is engaged.
GWARNING
Vehicles with level control:
The vehicle is lowered as soon as you discon-
nect the trailer cable. This could result in your
limbs or those of other people that are
between the vehicle body and tires or under-
neath the vehicle being trapped. There is a
risk of injury.
Make sure that nobody is in the immediate
vicinity of the wheel housings or under the
vehicle when you disconnect the trailer cable.
!Do not disconnect a trailer with an engaged
overrun brake. Otherwise, your vehicle could
be damaged by the rebounding of the overrun brake.
XShift the transmission to position P.
XApply the vehicle's electric parking brake.
XStart the engine.
XClose the doors and tailgate.
XApply the trailer's parking brake.
XDetach the trailer cable and decouple the
trailer.
XSwitch off the engine.
Permissible trailer loads and drawbar
loads
Weight specifications
Maximum allowable gross mass
The gross vehicle weight of the trailer is calcu-
lated by adding the weight of the trailer to the
weight of the load and equipment on the trailer. You will find installing dimensions and loads
under "Technical data" (
Ypage 444).
Permissible noseweight
You will find installing dimensions and loads
under "Technical data" (Ypage 444).
Loading a trailer
RWhen loading the trailer, make sure that nei-
ther the permissible gross weight of the trailer
nor the gross vehicle weight are exceeded.
The permissible gross vehicle weight is indi-
cated on the identification plate located on
the B-pillar on the driver's side of the vehicle.
You can find the maximum permissible values
on the type plates of your vehicle and the
trailer. When calculating how much weight
Towing a trailer261
Driving and parking
Z
the vehicle and trailer may carry, pay atten-
tion to the respective lowest values.
RThe trailer drawbar load on the ball coupling
must be added to the rear axle load to avoid
exceeding the permissible gross axle weight.
The permissible gross vehicle weight is indi-
cated on the identification plate located on
the B-pillar on the driver's side of the vehicle.
iMercedes-Benz recommends a trailer load
where the trailer drawbar noseweight
accounts for 8 % to 15 % of the trailer's per-
missible gross weight.
iThe weight of additional accessories, pas-
sengers, and cargo reduces the permissible
trailer load and drawbar load for your vehicle.
Checking the vehicle and trailer weight
RTo check that the weights of the towing vehi-
cle and the trailer comply with the maximum
permissible values, have the vehicle/trailer
combination (including the driver, passen-
gers, and cargo with a fully laden trailer)
weighed on a calibrated weighbridge.
RCheck the gross axle weight rating of the front and rear axles, the gross weight of the trailer
and the trailer drawbar noseweight.
Removing the ball coupling
XRemove the spring cotter.
XRemove the bolt from the ball coupling
recess.
XRemove the ball coupling from the ball cou-
pling recess.
XClean the ball coupling if it is dirty.
XStow the ball coupling so that it cannot be
thrown around.
Observe the loading guidelines (
Ypage 329)
and the safety notes regarding stowage spaces
(
Ypage 330).
Information on cleaning and care of the trailer
tow hitch (
Ypage 366).
Trailer power supply
!
Accessories with a maximum power con-
sumption of 180 W can be connected to the
permanent power supply. You must not charge a trailer battery using the
power supply.
The trailer socket of your vehicle is equipped at
the factory with a permanent power supply.
The permanent power supply is supplied via
trailer socket pin 4.
The trailer's permanent power supply is
switched off in the event of low vehicle supply
voltage and after six hours at the latest.
A qualified specialist workshop can provide
more information about installing the trailer
electrics.
262Towing a trailer
Driving an d parking
Safety systems
Display messagesPossible causes/consequences andMSolutions
!÷
Currently Unavaila‐ble See Operator'sManual
ABS (Anti-lock Brake System), BAS (Brake Assist), ESP®(Electronic
Stability Program), ESP®trailer stabilization, PRE‑ SAFE®, the HOLD
function, hill start assist, Crosswind Assist, STEER CONTROL, Active
Lane Keeping Assist and Active Blind Spot Assist are temporarily
unavailable.
COLLISION PREVENTION ASSIST PLUS, BAS PLUS with Cross-Traffic
Assist, PRE ‑SAFE
®PLUS and PRE ‑SAFE®Brake may also have failed.
In addition, the ÷,åand! warning lamps light up in the
instrument cluster.
ATTENTION ASSIST is deactivated.
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, BAS, ESP®, ESP®trailer stabilization, PRE‑ SAFE®, the HOLD
function, hill start assist, Crosswind Assist, STEER CONTROL, Active
Lane Keeping Assist and Active Blind Spot Assist are unavailable due
to a malfunction.
COLLISION PREVENTION ASSIST PLUS, BAS PLUS with Cross-Traffic
Assist, PRE ‑SAFE
®PLUS and PRE‑SAFE®Brake may also have failed.
The $ (USA only) or J(Canada only), ÷,åand!
warning lamps in the instrument cluster also light up.
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 affected.
The braking distance in an emergency braking situation can increase.
Display messages281
On-board computer and displays
Z
Display messagesPossible causes/consequences andMSolutions
If ESP®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.
÷
Currently Unavaila‐ble See Operator' sManual
ESP®,ES P®trailer stabilization ,BAS, PRE ‑SAFE®, th eHOLD function ,
hill start assist ,Crosswin dAssist, STEE RCONTROL, Active Lan e
Keepin gAssis tand Active Blind Spot Assis tare unavailable due to a
malfunction .
COLLISION PREVENTION ASSIST PLUS, BA SPLU Swit hCross-Traffic
Assist, PRE ‑S AF E
®PLU Sand PRE ‑SAFE®Brake may also hav efailed.
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.
282Display messages
On-board computer and displays
Display messagesPossible causes/consequences andMSolutions
÷
Inoperative SeeOperator'sManual
ES P®,ES P®trailer stabilization ,BAS, PRE ‑SAFE®, th eHOLD function ,
hill start assist ,Crosswin dAssist, STEE RCONTROL, Active Lan e
Keepin gAssis tand Active Blind Spot Assis tare unavailable due to a
malfunction .
COLLISION PREVENTION ASSIST PLUS, BA SPLU Swit hCross-Traffic
Assist, PRE ‑S AF E
®PLU Sand PRE ‑SAFE®Brake may also hav efailed.
In addition ,th e÷ andå warning lamp sligh tup in th einstru-
men tcluster.
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.
XDrive on carefully.
XVisit aqualified specialist workshop immediately.
T!
÷
Inoperative SeeOperator' sManual
EB D(electronic brak eforce distribution), ABS, ES P®,ES P®trailer sta-
bilization ,BAS, PRE‑ SAF E®,th eHOLD function ,hill start assist ,Cross-
win dAssist, STEE RCONTROL, Active Lan eKeepin gAssis tand Active
Blind Spot Assis tare unavailable due to amalfunction .
COLLISION PREVENTION ASSIST PLUS, BA SPLU Swit hCross-Traffic
Assist, PRE ‑S AF E
®PLU Sand PRE ‑S AF E®Brake may also hav efailed.
In addition ,th e÷, åand! warning lamp sligh tup in th e
instrumen tcluste rand awarning tone sounds.
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 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.
Display messages28 3
On-board computer and displays
Z