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218Driving and operatingDeactivation
The system is deactivated by
pressing a; the LED in the button
extinguishes.
The system is deactivated
automatically when a trailer is
detected.
Fault
The system performance may be
affected by:
● Windscreen not clean or affected
by foreign items, e.g. stickers
● Close vehicles ahead
● Banked roads
● Winding or hilly roads
● Road edges
● Roads with poor lane markings
● Sudden lighting changes
● Adverse environmental conditions e.g. heavy rain or
snow
● Vehicle modifications, e.g. tyres.Switch off the system if the system is
disturbed by tar marks, shadows,
road cracks, temporary or
construction lane markings, or other
road imperfections.9 Warning
Always keep your attention on the
road and maintain proper vehicle
position within the lane, otherwise
vehicle damage, injury or death
could occur.
Lane keep assist does not
continuously steer the vehicle.
The system may not keep the
vehicle in the lane or give an alert,
even if a lane marking is detected.
The steering of the lane keep
assist may not be sufficient to
avoid a lane departure.
The system may not detect hands-
off driving due to external
influences (road condition and
surface, weather etc). The driver
has full responsibility to control the
vehicle and is always required to keep the hands on the steeringwheel while driving.
Using the system while towing a
trailer or on slippery roads could
cause loss of control of the vehicle
and a crash. Switch the system off.
Page 226 of 317

224Driving and operatingTrailer hitch
General information
Only use towing equipment that has
been approved for your vehicle.
Entrust retrofitting of towing
equipment to a workshop. It may be
necessary to make changes that
affect the cooling system, heat
shields or other equipment.
The bulb outage detection function for trailer brake light cannot detect a
partial bulb outage, e.g. in case of four
times five watt bulbs, the function only detects lamp outage when only a
single five Watt lamp remains or none
remain.
Fitting of towing equipment could
cover the opening of the towing eye.
If this is the case use the coupling ball bar for towing. Always keep the
coupling ball bar in the vehicle when
not in use.Driving characteristics and
towing tips
Before attaching a trailer, lubricatethe coupling ball. However, do not do
so if a stabiliser, which acts on the
coupling ball, is being used to reduce snaking movements.
During trailer towing do not exceed a
speed of 80 km/h. A maximum speed
of 100 km/h is only appropriate if an
oscillation damper is used and the
permissible gross trailer weight does
not exceed the vehicle’s curb weight.
For trailers with low driving stability
and caravan trailers, the use of an
oscillation damper is strongly
recommended.
If the trailer starts snaking, drive more
slowly, do not attempt to correct the
steering and brake sharply if
necessary.
When driving downhill, drive in the
same gear as if driving uphill and
drive at a similar speed.
Adjust tyre pressure to the value
specified for full load 3 295.Trailer towing
Trailer loadsThe permissible trailer loads are
vehicle and engine-dependent
maximum values which must not be
exceeded. The actual trailer load is the difference between the actual
gross weight of the trailer and the
actual coupling socket load with the
trailer coupled.
The permissible trailer loads are
specified in the vehicle documents. In
general, they are valid for gradients
up to 12%.
The permissible trailer load applies
up to the specified incline and at sea
level. Since engine power decreases
as altitude increases due to the air
becoming thinner, therefore reducing
climbing ability, the permissible gross train weight also decreases by 10%for every 1000 metres of altitude. The gross train weight does not have to be
reduced when driving on roads with
slight inclines (less than 8%, e.g.
motorways).
Page 230 of 317
228Driving and operatingOpen the protective flap and turn the
key to position c to unlock the
coupling ball bar.
Pull out rotary handle and turn
clockwise as far as it will go. Pull out coupling ball bar downwards.
Insert sealing plug in opening.
Fold away connecting socket.
On Sports Tourer insert cover into
rear bumper as shown in the
illustration.
Stow the coupling ball bar in the bag
and secure by fixing the strap through the rear right lashing eye. Wrap
around twice and tighten the strap to
secure the bag.
Trailer stability assist
If the system detects snaking
movements, engine power is reduced
and the vehicle/trailer combination is selectively braked until the snaking
ceases. While system is working keep
steering wheel as still as possible.
Trailer stability assist is a function of
the Electronic Stability Control 3 182.
Page 252 of 317

250Vehicle careNo.Circuit32DC transformer/LED display/
Electrical heater/Climate
control/Glow plug controller33Anti theft warning horn34Horn35Power outlet load compartment36Right high beam (Halogen)/
Right low beam (LED)37Left high beam (Halogen)38LED headlight/Automatic head‐
light range adjustment39Front fog light40Central Gateway Module41Water in fuel sensor/Water
pump42Manual headlight range adjust‐
ment43Fuel pump44Rear view camera/Inside rear
view mirror/Trailer moduleNo.Circuit45LED headlight left/Automatic
headlight range adjustment left46Instrument cluster47Steering column lock48Rear wiper49Outside rearview mirror50LED headlight right/Automatic
headlight range adjustment
right51Left low beam (LED)52Engine control module/Trans‐
mission control module53Diesel exhaust system54Windscreen wiper55Electrical rear seat folding56–57–
After having changed defective fuses,
close the fuse box cover and press
until it engages.
If the fuse box cover is not closed
correctly, malfunction may occur.
Instrument panel fuse boxThe fuse box is located behind a
cover.
Pull the cover on the left side to
remove.
Page 253 of 317
Vehicle care251No.Circuit1Rear seat heating (only for vehi‐cles without alarm horn)2Climate control system, fan3Power seat driver side4Power seat passenger side5–6Power window front7ABS8Heated steering wheel9Body control module 810Power window rear11Sunroof12Body control module 413Seat heating (only on vehicles
without alarm horn)14Exterior mirror15Body control module 116Body control module 7No.Circuit17Body control module 618Body control module 319Data link connector20Airbag system21Climate control system22Central locking system, tailgate23Electronic key system24Power seat memory function25Airbag system steering wheel26Ignition switch/Steering column
lock27Body control module 228USB socket29Cigarette lighter/Power outlet
front30Selector lever31Rear window wiper32Transmission control module
Page 262 of 317

260Vehicle carewheel and left side rear wheel. Theturn signal light at the current active
position is illuminated until sensor is
matched.
Consult a workshop for service. There are two minutes to match the first
wheel position, and five minutes
overall to match all four wheel
positions. If it takes longer, the
matching process stops and must be
restarted.
The tyre pressure sensor matching
process is:
1. Apply the parking brake.
2. Turn the ignition on.
3. On vehicles with automatic transmission: set the selector
lever to P.
On vehicles with manual
transmission: select neutral.
4. Midlevel display: Use MENU on the turn signal
lever to select the Vehicle
Information Menu ? in the
Driver Information Centre.
Uplevel display:Press p on the steering wheel to
open main menu page.
Select the Info page with Q or P.
Confirm with 9.
5. Select the tyre pressure menu. Midlevel display:
Uplevel display:
6. Midlevel display:Press SET/CLR to begin the
sensor matching process. A
message requesting acceptance
of the process should be
displayed.
Press SET/CLR again to confirm
the selection. The horn sounds
twice to indicate that the receiver
is in relearn mode.
Uplevel display:
Press 9 to begin the sensor
matching process. The horn
sounds twice to indicate that the receiver is in relearn mode.
7. Start with the left side front wheel.
Page 265 of 317
Vehicle care2639Warning
Do not drive faster than 80 km/h.
Do not use for a lengthy period.
Steering and handling may be
affected.
If you have a flat tyre:
Apply the parking brake and engage
first gear, reverse gear or P.
On 5-door hatchback the tyre repair
kit is on the right side in the load
compartment behind a cover.
On Sports Tourer the tyre repair kit is
in a suitcase on the right side of the
load compartment behind a cover.
The suitcase is secured with a strap.
1. Remove the sealant bottle.
2. Insert thumb into the opening and
pull out the compressor.3. Remove the electrical connection cable and air hose from the
stowage compartments on the
underside of the compressor.
Page 275 of 317

Vehicle care273Towing
Towing the vehicle
Wrap a cloth around the tip of a flat
screwdriver to prevent paint damage.
Insert a screwdriver in the slot at the
lower part of the cap. Release the cap
by carefully moving the screwdriver
downwards.
The towing eye is stowed with the
vehicle tools 3 254.
Screw in the towing eye as far as it will
go until it stops in a horizontal
position.
Attach a tow rope – or better still a tow rod – to the towing eye.
The towing eye must only be used for
towing and not for recovering the
vehicle.
Switch on ignition to release steering wheel lock and to permit operation of
brake lights, horn and windscreen
wiper.
Caution
Deactivate the driver assistance
systems like active emergency
braking 3 198, otherwise the
vehicle may automatically brake during towing.
Switch the selector lever to neutral.
Release the parking brake.
Caution
Drive slowly. Do not drive jerkily.
Excessive tractive force can
damage the vehicle.
When the engine is not running,
considerably more force is needed to
brake and steer.
To prevent the entry of exhaust gases from the towing vehicle, switch on the
air recirculation and close the
windows.
Vehicles with automatic transmission: The vehicle must be towed facing
forwards, not faster than 80 km/h nor further than 100 km. In all other cases