Page 217 of 386

be fastened to the vehicle's trailer cou-
pling, not to the bumper or the axle.
Leave enough play in the chains to make
tight cornering possible.
R a separate brake system for certain types
of trailer.
R a safety switch for braked trailers. Check
the specific legal requirements applicable
to your state.
If the trailer detaches from the towing vehi-
cle, the safety switch applies the trailer's
brakes.
! Do not connect the trailer's brake system
(if featured) to the hydraulic brake system
of the towing vehicle, as the latter is equip- ped 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.
iThe vehicle's wiring harness features a
connection to the brake indicator lamp.
X Make sure that the automatic transmission
is set to position P.
X Apply the vehicle's parking brake.
X Close all doors and the tailgate.
X Couple up the trailer.
X Establish all electrical connections.
Towing a trailer
There are numerous legal requirements con-
cerning the towing of a trailer, e.g. speed
restrictions. Make sure that your car/trailer
combination complies with the local regula-
tions:
R in your place of residence
R in the location to which you are driving
The police and local authorities can provide
reliable information.
Observe the following when towing a trailer:
R To gain driving experience and to become
accustomed to the new handling charac- teristics, you should practice the following
in a traffic-free location:
- cornering
- stopping
- backing up
R Before driving, check:
- the trailer tow hitch
- the safety switch for braked trailers
- the safety chains
- electrical connections
- the lights
- the wheels
R Adjust the exterior mirrors to provide an
unobstructed view of the rear section of the
trailer.
R If the trailer has electronically controlled
brakes, pull away carefully. Brake manually
using the brake controller and check
whether the brakes function correctly.
R Secure any objects on the trailer to prevent
the cargo from slipping when the vehicle is
in motion.
R When you couple up a trailer, check at reg-
ular 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.
R Bear in mind that the handling will be less
stable when towing a trailer than when driv-
ing without one. Avoid sudden steering
movements.
R The 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.
R If possible, avoid abrupt braking. Depress
the brake pedal moderately at first, so that
the trailer can activate its own brakes. Thenincrease the pressure on the brake pedal.
R If the automatic transmission repeatedly
shifts between gears on uphill or downhill
Towing a trailer215
Driving and parking
Z
Page 218 of 386

gradients, 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.
R When 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
installed, the trailer brakes.
R If the coolant temperature increases dra-
matically while the air-conditioning system
is switched on, switch off the air-condition-
ing system.
Coolant heat can additionally be dissipated
by opening the windows and by setting the blower fan and the interior temperature to
maximum.
R When overtaking, pay particular attention
to the extended length of your vehicle/
trailer combination.
Due to the length of the vehicle/trailer
combination, 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.
! 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 automatic transmission
is set to position P.
X Apply the vehicle's parking brake. X
Close all doors and the tailgate.
X Apply the trailer's parking brake.
X Remove the trailer cable and decouple the
trailer.
Permissible trailer loads and drawbar
loads
Weight specifications
The gross trailer weight is calculated by add-
ing 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" ( Y page 381).
Loading a trailer
R
When loading the trailer, make sure that
neither the permissible gross weight of the
trailer nor the gross vehicle weight is
exceeded. The permissible gross vehicle
weight is indicated on the identification
plate on the B-pillar on the driver's side of
the vehicle.
You can find the maximum permissible val-
ues on the type plates of your vehicle and
the trailer. When calculating how much
weight the vehicle and trailer may carry,
pay attention to the respective lowest val-
ues.
R The 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 indicated on the identification
plate 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.
216Towing a trailer
Driving and parking
Page 219 of 386

iThe weight of other accessories, passen-
gers and loads reduces:
R the permissible trailer load
R the permissible noseweight that your
vehicle can tow
Checking the vehicle and trailer weight
RTo ensure compliance of the weight of the
towing vehicle and the trailer with the max-
imum permissible values, have the vehicle/
trailer combination (towing vehicle includ-
ing driver, passenger, load and fully laden
trailer) weighed on a calibrated weigh-
bridge.
R Check the gross axle weight rating of the
front and rear axles, the gross weight of the
trailer and trailer drawbar load.
Removing the ball coupling
X Observe the manufacturer's installation
instructions.
X Press the protective cap into the ball cou-
pling recess.
X Make sure that the protective cap is firmly
in place.
Storing the ball coupling
X Observe the manufacturer's installation
instructions.
Observe the loading guidelines ( Y page 274)
and the safety notes regarding stowage
spaces ( Y page 275).
Trailer 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.
! You can connect accessories with a max-
imum power consumption of 240 W to the
permanent power supply.
You must not charge a trailer battery using the power supply.
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.
Towing a trailer217
Driving and parking
Z
Page 220 of 386
Page 221 of 386
Useful information............................220
Important safety notes .....................220
Displays and operation .....................220
Menus and submenus ......................223
Display messages ............................. 235
Warning and indicator lamps in the instrument cluster ............................260
219
On-board computer and displays
Page 222 of 386

Useful information
iThis Operator's Manual describes all
models and all standard and optional equip- ment of your vehicle available at the time of
publication of the Operator's Manual.
Country-specific differences are possible.
Please note that your vehicle may not be
equipped with all features described. This
also applies to safety-related systems and
functions.
iRead the information on qualified special-
ist workshops ( Y page 27).
Important safety notes
GWARNING
If you operate information systems and com-
munication equipment integrated in the vehi-
cle while driving, you will be distracted from
traffic conditions. You could also lose controlof the vehicle. There is a risk of an accident.
Only operate the equipment when the traffic
situation permits. If you are not sure that this
is possible, park the vehicle paying attention
to traffic conditions and operate the equip-
ment when the vehicle is stationary.
You must observe the legal requirements for
the country in which you are currently driving when operating the on-board computer.
GWARNING
If the instrument cluster has failed or mal-
functioned, you may not recognize function
restrictions in systems relevant to safety. The operating safety of your vehicle may be
impaired. There is a risk of an accident.
Drive on carefully. Have the vehicle checked
at a qualified specialist workshop immedi-
ately.
The on-board computer only shows messages
or warnings from certain systems in the mul- tifunction display. You should therefore make sure your vehicle is operating safely at all
times.
If the operating safety of your vehicle is
impaired, pull over as soon as it is safe to do
so. Contact a qualified specialist workshop.
For an overview, see the instrument panel
illustration (
Y page 33).
Displays and operation
Coolant temperature display
GWARNING
Opening the hood when the engine is over-
heated or when there is a fire in the engine
compartment could expose you to hot gases
or other service products. There is a risk of
injury.
Let an overheated engine cool down before
opening the hood. If there is a fire in the
engine compartment, keep the hood closed
and contact the fire department.
The coolant temperature gauge is in the
instrument cluster on the left-hand side.
Under normal operating conditions and with
the specified coolant level, the coolant tem-
perature may rise to 248 ‡ (120 †).
! A display message is shown if the coolant
temperature is too high.
If the coolant temperature is over 248 ‡
(120 †), do not continue driving. The
engine will otherwise be damaged.
Tachometer
The red band in the tachometer indicates the
engine's overrevving range.
! Do not drive in the overrevving range, as
this could damage the engine.
The fuel supply is interrupted to protect the
engine when the red band is reached.
220Displays and operation
On-board computer and displays
Page 223 of 386

Outside temperature display
You should pay special attention to road con-
ditions when temperatures are around freez-
ing point.
Bear in mind that the outside temperature
display indicates the temperature measured
and does not record the road temperature.
The outside temperature display is in the mul- tifunction display ( Y page 222).
Changes in the outside temperature are dis-
played after a short delay.
Speedometer with segments
The segments in the speedometer indicate
which speed range is available.
R Cruise control activated ( Y page 175):
The segments light up from the stored
speed to the maximum speed.
R DISTRONIC PLUS activated ( Y page 176):
One or two segments in the set speed
range light up.
R DISTRONIC PLUS detects a vehicle in front
that is driving at a slower speed than the
stored speed:
The segments between the speed of the
vehicle in front and the stored speed light
up.
Operating the on-board computer
Overview
:Multifunction display
;Switches on the Voice Control System
(see the separate operating instructions)
=Right control panel
?Left control panel
ABack button
X To activate the on-board computer: turn
the SmartKey to position 1 in the ignition
lock.
You can control the multifunction display and
the settings in the on-board computer using
the buttons on the multifunction steering
wheel.
Displays and operation221
On-board computer and displays
Z
Page 224 of 386

Left control panel
= ;RCalls up the menu and menu bar
9 :Press briefly:
R Scrolls in lists
R Selects a submenu or function
R In the
Audio menu: selects a
stored station, an audio track or
a video scene
R In the
Tel (telephone) menu:
switches to the phone book and
selects a name or telephone
number
9 :Press and hold:
R In the
Audio menu: selects the
previous/next station or selects
an audio track or a video scene
using rapid scrolling
R In the
Tel (Telephone) menu:
starts rapid scrolling of the
phone book if it is open
aR Confirms a selection/display
message
R In the
Tel (Telephone) menu:
switches to the telephone book
and starts dialing the selected
number
R In the
Audio menu: stops the
station search function at the
desired station
Right control panel
~R Rejects or ends a call
R Exits phone book/redial mem-
ory
6RMakes or accepts a call
R Switches to the redial memory
W XRAdjusts the volume
8RMute
Back button
%Press briefly:
R Back
R Switches off the Voice Control
System (see the separate oper-
ating instructions)
R Hides display messages/calls
up the last
Trip menu function
used
R Exits the telephone book/redial
memory
%Press and hold:
R Calls up the standard display in
the
Trip menu
Multifunction display
:Text field
;Menu bar
=Drive program ( Y page 157)
?Transmission position ( Y page 157)
ATime
BPermanent display: outside temperature
or speed ( Y page 231)
222Displays and operation
On-board computer and displays