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244Driving and operating● Weather limits visibility, such asfog, rain, or snow.
● The sensor in the windscreen is blocked by snow, ice, slush, mud,dirt, windscreen damage or
affected by foreign items, e.g.
stickers.
● The sun is shining directly into the camera lens.
● Close vehicles ahead
● Banked roads
● Road edges
● Roads with poor lane markings
● Sudden lighting changes
● 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 tokeep 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.
Fuel
Fuel for petrol engines
Only use unleaded fuel that complies
with European standard EN 228 or
equivalent.
The engine is capable of running with
fuel that contains up to 10% ethanol
(e.g. named E10).
Use fuel with the recommended
octane rating. A lower octane rating can reduce engine power and torque
and slightly increases fuel
consumption.
Page 251 of 345

Driving and operating249Driving characteristics and
towing tips
Before attaching a trailer, lubricate
the 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 kerb 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 3 317.Trailer towing
Trailer loads The 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).The permissible gross train weight must not be exceeded. This weight is specified on the identification plate
3 302.
Vertical coupling load
The vertical coupling load is the load
exerted by the trailer on the coupling
ball. It can be varied by changing the
weight distribution when loading the
trailer.
The maximum permissible vertical
coupling load of:
● 60 kg (Grand Sport with all engines except B20DTH /
B20NFT / D20DTR)
● 75 kg (Sports Tourer, Country Tourer with all engines except
B20DTH / B20NFT / D20DTR)
● 90 kg (All bodystyles with engines B20DTH / B20NFT /
D20DTR)
is specified on the towing equipment
identification plate and in the vehicle
documents. Always aim for the
maximum load, especially in the case
of heavy trailers. The vertical coupling load should never fall below 25 kg.
Page 253 of 345

Driving and operating251Stow/hide coupling ball bar
Pull the grip located left of the number
plate under the rear bumper fascia at an angle of approx. 45° to the ground.
A buzzing tone sounds as a warning
when the release handle is pulled out and the ball neck is disengaged.
With the flat of the hand, swivel the
released coupling ball bar to the right
until it engages under the floor. Make sure that the release handle is back inits hidden initial position, otherwise
the buzzing tone will not stop.
9 Warning
Towing a trailer is permitted only
when the coupling ball bar is fitted correctly. If the coupling ball bar
does not engage correctly or if the
release handle is impossible to guide to its hidden initial position in the housing or if the buzzing tone
sounds after engaging the
coupling ball bar, seek the
assistance of a workshop.
Eye for break-away stopping cable
Attach break-away stopping cable to
eye.
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 the system is working
keep steering wheel as still as
possible.
Trailer stability assistant is a function
of the Electronic Stability Control
3 197.
Page 274 of 345
272Vehicle careNo.Circuit1–2–3ABS4–5–6Tailgate7Fog light8Memory module9Heated windscreen10Seat lumbar11DC/DC battery12Heated rear window13Heated mirror14–15–16Front wiper17Power seat, passengerNo.Circuit18Sunblind19Power seat, driver20–21Sunroof22Rear wiper/Airbag23Adaptive forward lighting24–25–26Transmission control module27Ignition/Instrument panel28–29Rear view camera/Air vent30Malfunction indicator light/
Trailer31–32Camera33Seat heat front34Seat heat rearNo.Circuit35Damping/All-wheel drive36Fuel system37–38–39–40Steering wheel lock41–42–43Heated steering wheel44Headlight range adjustment45–46Engine control module47–48DC/DC converter/Air vent/E-
Boost49Rear door control module50–51–
Page 276 of 345
274Vehicle careInstrument panel fuse box
In left-hand drive vehicles, the fuse
box is behind a cover in the
instrument panel.
Disengage cover at the side and
remove.
In right-hand drive vehicles, the fuse
box is located behind a cover in the
glovebox. Open the glovebox and
remove the cover.
No.Circuit1Left power window2Right power window3Body control module4Climate control fan5Body control module6Trailer provisions7Rear seat power folding8Body control module9Engine control module10Head-up display11NO x reduction/Pipe heater12NO
x reduction/Soot sensor13AdBlue module14Heated steering wheel15Transmission control module16Amplifier17Alarm
Page 277 of 345
Vehicle care275No.Circuit18Body control module19AdBlue module20Body control module21Body control module22Body control module23Electric steering wheel lock24Airbag25Diagnostic connector26Power outlet load compartment27EBCM valve28Police provision29–30–31Steering wheel controls32Ignition switch33Climate control34Central gateway moduleNo.Circuit35AUX/USB connector36Wireless charger37Rear wiper38OnStar module39Display40Parking assist41Overhead console42Infotainment SystemVehicle tools
Tools
Vehicles with spare wheel
The jack with wheel wrench, the tools,
an extension bolt for securing a
damaged wheel and the towing eye
are placed in the tool box below the
spare wheel in the load compartment. Spare wheel 3 288.
Page 284 of 345

282Vehicle care9Warning
Use of unsuitable tyres or wheel
covers could lead to sudden
pressure loss and thereby
accidents.
Vehicles with steel wheels: When
using locking wheel nuts, do not
attach wheel covers.
Tyre chains
Tyre chains are only permitted on the
front wheels.
Always use fine mesh chains that add no more than 10 mm to the tyre tread
and the inboard sides (including chain lock).9 Warning
Damage may lead to tyre blowout.
Tyre chains are only permitted on
tyres of size 215/60 R16, 215/55 R17 ,
225/55 R17 and 235/45 R18.
Temporary spare wheel
The use of tyre chains is not permitted on the temporary spare wheel.
Tyre repair kit
Minor damage to the tyre tread can be
repaired with the tyre repair kit.
Do not remove foreign bodies from
the tyres.
Tyre damage exceeding 4 mm or that is at tyre's side wall cannot be
repaired with the tyre repair kit.
9 Warning
Do not drive faster than 80 km/h.
Do not use for a lengthy period.
Steering and handling may be
affected.
Two types of tyre repair kit are
available:
● Type 1 indicated by the on/off
switch at the top of the
compressor.
Page 295 of 345

Vehicle care293Towing
Towing the vehicle
Wrap a cloth around the tip of a flat
screwdriver to prevent paint damage.
Insert the screwdriver in the slot at the
edge of the cap. Release the cap by
levering it out carefully.
The towing eye is stowed with the
vehicle tools 3 275.
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 3 218, 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 manual transmission
and All-wheel drive: If the vehicle is
towed with all four wheels on the
ground then there are no technical