Ball coupling recess
Holes in the ball coupling and ball coupling recess
X Insert the ball coupling horizontally into ball
coupling recess 0044in the direction of the
arrow until the holes in ball coupling 0087are
in line with the holes in ball coupling
recess 0085. Bolt
X Slide bolt 0083into the hole in the ball cou-
pling recess and the ball coupling to the
stop. Bolt and spring cotter
X Secure the bolt using spring cotter 0084. Correctly installed and secured ball coupling
X Check the ball coupling, bolt and spring
cotter for correct installation.
If the ball coupling cannot be correctly moun-
ted, remove the ball coupling. Under these
circumstances, the ball coupling must not be used for trailer towing.
If the ball coupling cannot be locked and the
key cannot be removed, remove the ball cou-
pling and clean it. If the ball coupling can still
not be installed (locked) after it has been
cleaned, remove the ball coupling. The trailer tow hitch must then not be used to tow a
trailer, as safe operation cannot be guaran-
teed.
Have the entire trailer tow hitch checked at aqualified specialist workshop. Coupling up a trailer
! Do not connect the trailer's brake system
(if featured) to the hydraulic brake system Towing a trailer
267Driving and parking Z
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.
X Make sure that the automatic transmission
is set to position P.
X Apply the vehicle's electric parking brake.
X Start the engine.
X Vehicles with the AIRMATIC package:
select highway level.
X Vehicles with ADS: set ADS toAUTOor
COMF.
X Switch off the engine.
X Close all doors and the tailgate.
X Couple up the trailer.
X Establish all electrical connections.
X Check that the trailer lighting system is
working.
i Vehicles with the AIRMATIC package:
with a trailer attached, the vehicle will
always remain at highway level. When cou-
pling up a trailer, please observe the fol-
lowing:
R Unless highway level has been set man-
ually, the vehicle is automatically low-
ered to highway level. This is the case if a
speed of 5 mph (8 km/h) is reached.
R High-speed level 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).
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 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. 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:
- trailer tow hitch
- safety switch for braked trailers
- safety chains
- electrical connections
- lights
- 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 268
Towing a trailerDriving and parking
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, do not brake suddenly, but
instead depress the brake pedal moder-
ately at first so that the trailer can activate its brakes. Then increase the pressure on
the brake pedal.
R If the automatic transmission repeatedly
shifts between gears on uphill or downhill
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 also be dissipated by
opening the windows and switching the ventilation blower and the interior temper-
ature to the highest level.
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
G
WARNING
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. G
WARNING
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 rebound- ing of the overrun brake.
X Make sure that the automatic transmission
is set to position P.
X Apply the vehicle's electric parking brake.
X Start the engine.
X Close all doors and the tailgate.
X Apply the trailer's parking brake. Towing a trailer
269Driving and parking Z
R
brake sharply
R change direction suddenly
R are involved in an accident Trailer power supply
! 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 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. Towing a trailer
271Driving and parking Z
Assistance menu
Introduction In the
DriveAssist
DriveAssist menu, you have the fol-
lowing options:
R Displaying the assistance graphic
(Y page 283)
R Activating/deactivating the distance warn-
ing function (Y page 283)
R Activating/deactivating PRE-SAFE ®
Brake
(Y page 284)
R Activating/deactivating ATTENTION
ASSIST (Y page 284)
R Activating/deactivating Blind Spot Assist
or Active Blind Spot Assist (Y page 284)
R Activating/deactivating Lane Keeping
Assist or Active Lane Keeping Assist
(Y page 284)
Displaying the assistance graphic X
Press the 0059or0065 button on the steer-
ing wheel to select the DriveAssist DriveAssistmenu.
X Press 0063or0064 to select Assistance Assistance
Graphic
Graphic.
X Press the 0076button.
The multifunction display shows the DIS-
TRONIC PLUS distance display in the assis- tance graphic.
The assistance graphic displays the status of and information from the following driving
systems or driving safety systems:
R ATTENTION ASSIST (Y page 241)
R DISTRONIC PLUS (Y page 213)
R Lane Keeping Assist (Y page 247) or Active
Lane Keeping Assist (Y page 252)
R Distance warning function (Y page 70)
R PRE-SAFE ®
Brake (Y page 76)
R DSR (Y page 258)
R Off-road program (vehicles with the
ON&OFFROAD package) (Y page 259)
Activating/deactivating the distance
warning function X
Press the 0059or0065 button on the steer-
ing wheel to select the DriveAssist DriveAssistmenu.
X Press 0063or0064 to select Distance
Distance
Warning
Warning.
X Press the 0076button.
The current selection is displayed.
X To activate/deactivate: press the0076
button again.
When the distance warning function is
deactivated, the assistance graphic shows
the 00D4 symbol in the multifunction dis-
play.
Further information on the distance warning
function (Y page 70). Menus and sub
menus
283On-board computer and displays Z
Activating/deactivating PRE-SAFE
®
Brake PRE
‑SAFE ®
Brake is only available in vehicles
with DISTRONIC PLUS.
X Press 0059or0065 on the steering wheel
to select the DriveAssist
DriveAssist menu.
X Press the 0063or0064 button to select
PRE-SAFE Brake
PRE-SAFE Brake.
X Press the 0076button.
The current selection is displayed.
X To activate/deactivate: press the0076
button again.
When PRE-SAFE ®
Brake is deactivated, the
assistance graphic shows the 00D4symbol
in the multifunction display.
For more information on PRE‑SAFE ®
Brake,
see (Y page 76).
Activating/deactivating ATTENTION
ASSIST X
Press the 0059or0065 button on the steer-
ing wheel to select the DriveAssist DriveAssistmenu.
X Press the 0063or0064 button to select
ATTENTION ASSIST
ATTENTION ASSIST .
X Press the 0076button.
The current selection is displayed.
X To activate/deactivate: press the0076
button again.
When ATTENTION ASSIST is deactivated,
the 00D7 symbol appears in the multifunc-
tion display in the assistance graphics dis-
play.
For further information about ATTENTION
ASSIST, see (Y page 241).
Activating/deactivating Blind Spot
Assist X
Press 0059or0065 on the steering wheel
to select the DriveAssist
DriveAssist menu.
X Press the 0063or0064 button to select
Blind Spot Assist
Blind Spot Assist . X
Press the 0076button.
The current selection is displayed.
X To activate/deactivate: press the0076
button again.
For further information about Active Blind
Spot Assist, see (Y page 249).
Activating/deactivating Lane Keeping
Assist X
Press 0059or0065 on the steering wheel
to select the DriveAssist DriveAssist menu.
X Press 0063or0064 to select Lane Keep‐
Lane Keep‐
ing Assist
ing Assist .
X Press the 0076button.
The current selection is displayed.
X Press 0076to confirm.
X Press the 0064or0063 button to set Off
Off,
Standard
Standard orAdaptive
Adaptive.
When Lane Keeping Assist or Active Lane
Keeping Assist is activated, the multifunc-
tion display shows the lane markings as
bright lines in the assistance graphic.
X Press the 0076button to save the setting.
For further information about Lane Keeping
Assist, see (Y page 247).
For further information about Active Lane
Keeping Assist, see (Y page 252). Maintenance menu
In the
Serv Servmenu, you have the following
options:
R Calling up display messages in message
memory (Y page 292)
R Restarting the tire pressure loss warning
system (Y page 414) 284
Menus and sub
menusOn-board computer and displays
R
Parking lamps
R Daytime running lamps
R Side marker lamps
R Surround lighting in the exterior mirrors
Activating/deactivating the interior light-
ing delayed switch-off
If you activate the Interior Lighting
Interior Lighting
Delay Delay function, the interior lighting remains
on for 20 seconds after you remove the
SmartKey from the ignition lock.
X Press the 0059or0065 button on the steer-
ing wheel to select the Sett
Sett menu.
X Press the 0064or0063 button to select the
Light Light submenu.
X Press 0076to confirm.
X Press the 0064or0063 button to select the
Interior Lighting Delay
Interior Lighting Delay function.
If the Interior
Interior Lighting
LightingDelay
Delayfunction
has been switched on, the vehicle interior is
displayed in orange in the multifunction
display.
X Press the 0076button to save the setting.
Vehicle submenu Activating/deactivating the automatic
door locking mechanism
If you activate the Automatic Door Lock Automatic Door Lock
function, the vehicle is centrally locked above
a speed of approximately 9 mph (15 km/h).
X Press the 0059or0065 button on the steer-
ing wheel to select the Sett
Settmenu.
X Press the 0064or0063 button to select the
Vehicle
Vehicle submenu.
X Press 0076to confirm.
X Press the 0064or0063 button to select the
Automatic Door Lock
Automatic Door Lock function.
When the Automatic
Automatic Door
DoorLock
Lockfunction
is activated, the vehicle doors are displayed
in orange in the multifunction display.
X Press the 0076button to save the setting.
For further information on the automatic lock- ing feature, see (Y page 90). Activating/deactivating the acoustic
locking verification signal
If you switch on the
Acoustic AcousticLock
Lockfunction,
an acoustic signal sounds when you lock the
vehicle.
X Press the 0059or0065 button on the steer-
ing wheel to select the Sett.
Sett. menu.
X Press 0064or0063 to select the Vehicle Vehicle
submenu.
X Press 0076to confirm.
X Press the 0064or0063 button to select the
Acoustic Lock
Acoustic Lock function.
If the Acoustic
Acoustic Lock
Lockfunction is activated,
the 0037 symbol in the multifunction dis-
play lights up orange.
X Press the 0076button to save the setting.
Activating/deactivating the radar sensor
system
X Press the 0059or0065 button on the steer-
ing wheel to select the Sett.
Sett. menu.
X Press 0064or0063 to select the Vehicle Vehicle
submenu.
X Press 0076to confirm.
X Press the 0063or0064 button to select
Radar Sensor (See Oper. Manual):
Radar Sensor (See Oper. Manual):.
You will see the selected setting: Enabled
Enabled
or Disabled Disabled.
X Press the 0076button to save the setting.
The following systems are switched off when the radar sensor system is deactivated:
R DISTRONIC PLUS (Y page 206)
R BAS PLUS (Y page 69)
R PRE-SAFE ®
Brake (Y page 76)
R Blind Spot Assist (Y page 245)
R Active Blind Spot Assist (Y page 249)
Convenience submenu Activating/deactivating the EASY-
ENTRY/EXIT feature
G
WARNING
When the EASY-ENTRY/EXIT feature adjusts
the steering wheel, you and other vehicle Menus and submenus
287On-board computer and displays
Z
Safety systems
Display messages
Possible causes/consequences and
0050
0050Solutions 002500E5
Currently Unavail‐ Currently Unavail‐
able See Opera‐ able See Opera‐
tor's Manual tor's Manual ABS (Anti-lock Braking System), ESP
®
(Electronic Stability Pro-
gram), BAS (Brake Assist), PRE-SAFE ®
, the HOLD function, hill
start assist, crosswind assistance and ESP ®
trailer stabilization
are temporarily unavailable.
COLLISION PREVENTION ASSIST, BAS PLUS and
PRE‑SAFE ®
Brake may also have failed.
In addition, the 00E5,00BBand0025 warning lamps light up in the
instrument cluster.
ATTENTION ASSIST is deactivated.
Possible causes are:
R Self-diagnosis is not yet complete.
R The on-board voltage may be insufficient.
G WARNING
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 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.
X Carefully 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 display message continues to be displayed: X Drive on carefully.
X Visit a qualified specialist workshop. 002500E5
Inoperative See Inoperative See
Operator's Manual Operator's Manual ABS, ESP
®
, BAS, PRE-SAFE ®
, the HOLD function, hill start assist,
crosswind assistance and ESP ®
trailer stabilization are unavailable
due to a malfunction.
COLLISION PREVENTION ASSIST, BAS PLUS and
PRE‑SAFE ®
Brake may also have failed.
The 0027 (USA only)/004D (Canada only),00E5,00BBand0025
warning lamps in the instrument cluster also light up.
ATTENTION ASSIST is deactivated.
G WARNING Display messages
293On-board computer and displays Z