
Coupling up a trailer
Observe the maximum permissible trailer
dimensions (width and length).
Most U.S. states and all Canadian provinces
require by law:
R safety chains between the towing vehicle
and the trailer. The chains should be cross-
wound under the trailer drawbar. They must
be fastened to the vehicle's trailer
coupling, not to the bumper or the axle.
Allow for enough play in the chains to
facilitate turning tight corners.
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
vehicle, 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
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.
i The vehicle's wiring harness features a
connection to the brake indicator lamp.XMake sure that the automatic transmission
is set to position P.XApply the vehicle's parking brake.XClose all doors and the tailgate.XCouple up the trailer.XEstablish all electrical connections.
Towing a trailer
There are numerous legal requirements
concerning the towing of a trailer, e.g. speed
restrictions. Make sure that your vehicle/
trailer combination complies with the local
requirements not only in your area of
residence but also at any location to which
you are traveling. The police and local
authorities can provide reliable information.
Please observe the following when towing a
trailer:
R To acquaint yourself with driving with a
trailer and with the resulting changes to
handling, you should practice cornering,
stopping and reversing in a traffic-free
location.
R Before driving, check:
- the trailer tow hitch
- the safety switch for braked trailers
- the safety chains
- the 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 features electronically
controlled brakes, pull away the vehicle/
trailer combination carefully, manually
brake using the brake controller, and check
the brakes for correct function.
R Secure any objects on the trailer to prevent
the cargo from slipping when the vehicle is
in motion.
R If you couple up a trailer, regularly check
the cargo for secure fastening and make
sure that the trailer lamps and (if
applicable) the trailer brakes are
functioning correctly.
R Bear in mind that the handling will be less
stable when towing a trailer than when
driving 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.162Trailer towingDriving and parking

! If the coolant temperature is too high a
display message is shown.
If the coolant temperature rises above
248 ‡(120 †), do not drive any further as
this could damage the engine.
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.
Outside temperature display
The outside temperature display is in the
multifunction display ( Y page 168).
GWARNING
The outside temperature indicator is not
designed to serve as an ice-warning device
and is therefore unsuitable for that purpose.
Indicated temperatures just above the
freezing point do not guarantee that the road
surface is free of ice. The road may still be icy,
especially in wooded areas or on bridges.
Changes in the outside temperature are
displayed after a short delay.
Speedometer with segments
The segments in the speedometer indicate
which speed range is available.
Cruise control ( Y page 151) activated:
The segments light up from the stored speed
to the maximum speed.
Operating the on-board computer
Overview
The on-board computer is activated as soon
as you 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.
:Multifunction display;Right control panel=To switch on the Voice Control System;
see the separate operating instructions?Back buttonALeft control panelDisplays and operation167On-board computer and displaysZ

Time/date
This submenu is only available on vehicles
with Audio 20. To set the time and the date
for vehicles with COMAND, see the separate
operating instructions.
In the Time/date submenu, you can set the
time and date.
XPress the = or ; button on the
steering wheel to select the Settings
menu.XPress the : or 9 button to select the
Time/Date submenu.XPress the a button to confirm.XPress the : or 9 button to select
Time: or Date: .
The current time or date set is displayed.XPress a to change the setting.XPress the = or ; button to select the
display you want to change: hour, minute,
day, month, year.XPress the : or 9 button to set the
selected display.XPress the a button to store the entry.
Lights
Switching the daytime running lamps on/
off
This function is not available in Canada.
If you have activated the Daytime Running
Lights: function and the light switch is in the
c or à position, the daytime running
lamps are switched on automatically during
the day when the engine is running.
In the dark, the following also light up:
R the low-beam headlamps
R the parking lamps
R the tail lamps
R the license plate lamp
R the side marker lamps
XPress the = or ; button on the
steering wheel to select the Settings
menu.XPress the : or 9 button to select the
Lights submenu.XPress the a button to confirm.XPress the : or 9 button to select the
Daytime Running Lights: function.
You will see the selected setting: Enabled
or Disabled .XPress the a button to save the setting.
Activating/deactivating surround
lighting and exterior lighting delayed
switch-off
If you have activated the Lighting: function
and the light switch is in the c or Ã
position, the following functions are active
when it is dark:
R Surround lighting: the exterior lighting
remains lit for 40 seconds after unlocking
with the key. The exterior lighting switches
off when you open the driver's door.
R Exterior lighting delayed switch-off: the
exterior lighting remains lit for 60 seconds
after the engine has been switched off. If
you close all the doors, the exterior lighting
goes off after 15 seconds.
If you activate the Lighting: function, the
following light up depending on the vehicle's
equipment:
R the parking lamps
R the fog lamps
R the low-beam headlamps
R the daytime running lamps
R the side marker lamps
XPress the = or ; button on the
steering wheel to select the Settings
menu.XPress the : or 9 button to select the
Lights submenu.XPress the a button to confirm.176Menus and submenusOn-board computer and displays

XPress the : or 9 button to select the
Locator Lighting: function.
You will see the selected setting: Enabled
or Disabled .XPress the a button to save the setting.
Deactivating delayed switch-off of the
exterior lighting temporarily:
XBefore leaving the vehicle, turn the
SmartKey to position 0 in the ignition lock.XTurn the SmartKey to position 2 in the
ignition lock and back to position 0.
The exterior lighting delayed switch-off is
deactivated.
Delayed switch-off of the exterior lighting is
reactivated the next time you start the
engine.
Activating/deactivating the interior
lighting delayed switch-off
If you activate the Interior Lighting
Delay function, the interior lighting remains
on for 20 seconds after you remove the
SmartKey from the ignition lock.
XPress the = or ; button on the
steering wheel to select the Settings
menu.XPress the : or 9 button to select the
Lights submenu.XPress the a button to confirm.XPress the : or 9 button to select the
Interior Lighting Delay: function.
You will see the selected setting: Enabled
or Disabled .XPress the a button to save the setting.
Vehicle
Activating/deactivating the automatic
door locking feature
If you select the Automatic Door Lock:
function, the vehicle is centrally locked above
a speed of around 9 mph (15 km/h).
i For further information on the automatic
locking feature, see ( Y page 76).
XPress the = or ; button on the
steering wheel to select the Settings
menu.XPress the : or 9 button to select the
Vehicle submenu.XPress the a button to confirm.XPress the : or 9 button to select the
Automatic Door Lock function.
You will see the selected setting: Enabled
or Disabled .XPress the a button to save the setting.
Activating/deactivating the acoustic
locking verification signal
If you activate the Acoustic Lock
feedback function, an audible signal sounds
depending on the vehicle's date of
manufacture:
R when locking
or
R once when unlocking and three times when
locking
XPress the = or ; button on the
steering wheel to select the Settings
menu.XPress the : or 9 button to select the
Vehicle submenu.XPress the a button to confirm.XPress the : or 9 button to select the
Acoustic Lock feedback: function.
You will see the selected setting: On or
Off .XPress the a button to save the setting.
Convenience
Activating/deactivating the EASY-
ENTRY/EXIT feature
You can use the Easy Entry/Exit: function
to activate or deactivate the EASY ENTRY/
EXIT feature ( Y page 96).
Menus and submenus177On-board computer and displaysZ

GWARNING
You must make sure no one can become
trapped or injured by the moving steering
wheel when the easy-entry/exit feature is
activated.
To stop steering wheel movement, move
steering wheel adjustment lever or press one
of the memory position buttons.
Do not leave children unattended in the
vehicle, or with access to an unlocked vehicle.
Children could open the driver's door and
unintentionally activate the easy-entry/exit
feature, which could result in an accident
and/or serious personal injury.
XPress the = or ; button on the
steering wheel to select the Settings
menu.XPress the : or 9 button to select the
Convenience submenu.XPress the a button to confirm.XPress the : or 9 button to select the
Easy Entry/Exit function.
You will see the selected setting: Enabled
or Disabled .XPress the a button to save the setting.
Switching the Fold in mirrors when
locking function on/off
This function is only available in Canada.
If you switch on the Fold Mirrors in when
Locking function, the exterior mirrors fold in
when you lock the vehicle. If you unlock the
vehicle and then open the driver's or front-
passenger door, the exterior mirrors fold out
again.
If you have switched the function on and you
fold the exterior mirrors in using the button
on the door (Y page 98), they will not fold out
automatically. The exterior mirrors can then
only be folded out using the button on the
door.
XPress the = or ; button on the
steering wheel to select the Settings
menu.XPress the : or 9 button to select the
Convenience submenu.XPress the a button to confirm.XPress the : or 9 to select the Fold
Mirrors in when Locking: function.
You will see the selected setting: Enabled
or Disabled .XPress the a button to save the setting.
Resetting to factory settings
For safety reasons, the Daytime Running
Lights: function in the Lights submenu is
only reset when the vehicle is stationary.
XPress the = or ; button on the
steering wheel to select the Settings
menu.XPress the : or 9 button to select the
Factory Setting submenu.XPress the a button to confirm.
The Reset All Settings? message
appears.XPress the : or 9 button to select
No or Yes .XPress the a button to confirm the
selection.
If you select Yes, the multifunction display
shows a confirmation message.178Menus and submenusOn-board computer and displays

Safety systemsDisplay messagesPossible causes/consequences and M Solutions!÷
Currently
Unavailable See
Operator's ManualGRisk of accident
ABS (Anti-lock Braking System), ESP ®
(Electronic Stability
Program), BAS (Brake Assist), hill start assist and ESP ®
trailer
stabilization are temporarily unavailable.
In addition, the ä, å and ! warning lamps light up in
the instrument cluster.
The self-diagnosis function might not be complete, for example.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
XCarefully drive a suitable distance making slight steering
movements at a speed above 12 mph (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.GRisk of accident
ABS, ESP ®
, BAS, hill start assist and ESP ®
trailer stabilization are
temporarily unavailable.
In addition, the ä, å and ! warning lamps light up in
the instrument cluster.
For example, the on-board voltage may be insufficient.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
XDrive on carefully.
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.180Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M Solutions!÷
Inoperative See
Operator's ManualGRisk of accident
ABS, ESP ®
, BAS, hill start assist and ESP ®
trailer stabilization are
unavailable due to a malfunction.
The $ (USA only)/ J (Canada only), ä, å
and ! warning lamps in the instrument cluster also light up.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
XDrive on carefully.XVisit a qualified specialist workshop immediately.÷
Currently
Unavailable See
Operator's ManualGRisk of accident
ESP ®
, BAS, hill start assist and ESP ®
trailer stabilization are
temporarily unavailable.
In addition, the ä and å warning lamps light up in the
instrument cluster.
The self-diagnosis function might not be complete, for example.
The brake system continues to function normally, but without the
functions listed above.
XCarefully drive a suitable distance making slight steering
movements at a speed above 12 mph (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.GRisk of accident
If the display message is shown and the ä warning lamp flashes
at the same time, the Electronic Traction System is deactivated.
Otherwise, the brakes on the drive wheels could overheat.
XLet the brakes cool down until the display message disappears
and the ä warning lamp goes out.
The Electronic Traction System is activated again.Display messages181On-board computer and displaysZ

Display messagesPossible causes/consequences and M Solutions÷
Inoperative See
Operator's ManualGRisk of accident
ESP ®
, hill start assist and ESP ®
trailer stabilization are unavailable
due to a malfunction.
In addition, the ä and å warning lamps light up in the
instrument cluster.
The brake system continues to function normally, but without the
functions listed above.
XDrive on carefully.XVisit a qualified specialist workshop.T !
÷
Inoperative See
Operator's ManualGRisk of accident
EBD (electronic brake force distribution), ABS, ESP ®
, BAS and hill
start assist are unavailable due to a malfunction.
In addition, the ä, å and ! warning lamps light up in
the instrument cluster and a warning tone sounds.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
XDrive on carefully.XVisit a qualified specialist workshop immediately.#
Check Brake Pad
WearThe brake pads/linings have reached their wear limit.XVisit a qualified specialist workshop.182Display messagesOn-board computer and displays