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Driving and operating257Checking the tensioning of the
coupling ball bar
● Red marking on rotary knob must
point towards green marking on
coupling ball bar.
● The gap between the rotary knob
and the coupling ball bar must be approx. 6 mm.
● The key must be in position c.
Otherwise, the coupling ball bar must be tensioned before being inserted:
● Unlock coupling ball bar by turning key to position c.
● Pull out rotary knob and turn
clockwise as far as it will go.
Inserting the coupling ball bar
Insert the tensioned coupling ball bar
in the opening and push firmly
upwards until it audibly engages.
The rotary handle snaps back into its
original position, resting against the
coupling ball bar without a gap.9 Warning
Do not touch rotary handle during
insertion.
Lock the coupling ball bar by turning
the key to position e. Remove the key
and close the protective flap.
Eye for break-away stopping cable
Page 260 of 341

258Driving and operatingAttach breakaway stopping cable to
eye.
Check that the coupling ball bar is correctly installed
● Green marking on rotary knob must point towards green
marking on coupling ball bar.
● There must be no gap between the rotary handle and the
coupling ball bar.
● The coupling ball bar must be firmly engaged in the opening.
● The coupling ball bar must be locked and the key removed.9Warning
Towing a trailer is permitted only
when a coupling ball bar is fitted correctly. If the coupling ball bardoes not engage correctly, seekthe assistance of a workshop.
Dismounting the coupling ball bar
Open 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 socket.
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 (TSA) is a
function of the Electronic Stability
Control 3 218.
Page 263 of 341
Vehicle care261● Since the durability of AdBlue islimited to two years, fluid should
be exchanged if it is too old. Seek the assistance of a workshop.
● Fit the number plate if necessary.
End-of-life vehicle recovery
Information on end-of-life vehicle
recovery centres and the recycling of
end-of-life vehicles is available on our website, where legally required. Only
entrust this work to an authorised
recycling centre.
Gas vehicles must be recycled by a
service centre authorised for gas
vehicles.Vehicle checks
Performing work9 Warning
Only perform engine compartment
checks when the ignition is off.
The cooling fan may start
operating even if the ignition is off.
9 Danger
The ignition system uses
extremely high voltage. Do not
touch.
Bonnet
Opening
Pull the release lever and return it to
its original position.
Page 266 of 341

264Vehicle care
If the cooling system is cold, the
coolant level should be above the
filling line mark. Top-up if the level is low.
9 Warning
Allow the engine to cool before
opening the cap. Carefully open
the cap, relieving the pressure
slowly.
To top-up, use a 1:1 mixture of
approved coolant concentrate mixed
with clean tap water. If no coolant
concentrate is available, use clean
tap water. Install the cap tightly.
Engine B16DTH: After starting the
engine, set the heating to warmest
temperature and the fan speed to at
least first level for approx. five
minutes. This will ensure that the air
within the cooling system escapes.
Have the coolant concentration
checked and have the cause of the
coolant loss remedied by a workshop.
Power steering fluidCaution
Extremely small amounts of
contamination can cause steering
system damage and cause it to not work properly. Do not allow
contaminates to contact the fluid
side of the reservoir cap/dipstick or
from entering the reservoir.
Power steering fluid level normally
does not have to be checked. If an
unusual noise sounds during steering or the power steering reacts
unusually, seek the assistance of a workshop.
Page 267 of 341

Vehicle care265Washer fluid
Fill with clean water mixed with a
suitable quantity of approved
windscreen washer fluid which
contains antifreeze.
Caution
Only washer fluid with a sufficient
antifreeze concentration provides
protection at low temperatures or
a sudden drop in temperature.
Brakes
In the event of minimum thickness of
the brake lining, a squealing noise
sounds during braking.
Continued driving is possible but
have the brake lining replaced as
soon as possible.
Once new brake linings are installed,
do not brake unnecessarily hard for
the first few journeys.
Brake fluid9 Warning
Brake fluid is poisonous and
corrosive. Avoid contact with eyes, skin, fabrics and painted surfaces.
The brake fluid level must be betweenthe MIN and MAX marks.
If fluid level is below MIN seek the
assistance of a workshop.
Brake and clutch fluid 3 305.
Vehicle battery
The vehicle battery is maintenance-
free, provided that the driving profile
allows sufficient charging of the
battery. Short-distance-driving and
frequent engine starts can discharge
the battery. Avoid the use of
unnecessary electrical consumers.
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266Vehicle care
Batteries do not belong in household
waste. They must be disposed of at
an appropriate recycling collection
point.
Laying up the vehicle for more than
four weeks can lead to battery
discharge. Disconnect the clamp from the negative terminal of the vehicle
battery.
Ensure the ignition is switched off
before connecting or disconnecting
the vehicle battery.
Vehicle battery discharge protection
3 139.
Disconnecting the battery
If the vehicle's battery is to be
disconnected (e.g. for maintenance
work), the alarm siren must be
deactivated as follows: switch the
ignition on then off, then disconnect
the vehicle's battery within
15 seconds.
Replacing the vehicle battery Note
Any deviation from the instructions
given in this section may lead to
temporary deactivation or
disturbance of the stop-start system.
When the vehicle battery is being
replaced, please ensure that there
are no open ventilation holes in the
vicinity of the positive terminal. If a
ventilation hole is open in this area, it
must be closed off with a dummy cap, and the ventilation in the vicinity of the
negative terminal must be opened.
Only use vehicle batteries that allow the fuse box to be mounted above the
vehicle battery.
Ensure that the battery is always replaced by the same type of battery.We recommend that you have the
vehicle battery replaced by a
workshop.
Stop-start system 3 202.
Charging the vehicle battery9 Warning
On vehicles with stop-start
system, ensure that the charging potential does not exceed
14.6 volts when using a battery
charger. Otherwise the vehicle
battery might be damaged.
Jump starting 3 297.
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Vehicle care267Warning label
Meaning of symbols:● No sparks, naked flames or smoking.
● Always shield eyes. Explosive gases can cause blindness or
injury.
● Keep the vehicle battery out of reach of children.
● The vehicle battery contains sulphuric acid which could cause
blindness or serious burn
injuries.
● See the Owner's Manual for further information.
● Explosive gas may be present in the vicinity of the vehicle battery.
Diesel fuel system bleeding If the tank has been run dry, the diesel
fuel system must be bled. Switch on
the ignition three times for
15 seconds at a time. Then crank the
engine for a maximum of 40 seconds. Repeat this process after
no less than five seconds. If the
engine fails to start, seek the
assistance of a workshop.Wiper blade replacement
Lift the wiper arm until it stays in the
raised position, press button to
disengage the wiper blade and
remove.
Attach the wiper blade slightly angled
to the wiper arm and push until it
engages.
Lower wiper arm carefully.
Page 283 of 341
Vehicle care281No.Circuit1–2Trailer outlet3Parking assist4Selective catalytic reduction
system5–6–7Power seat8–9Selective catalytic reduction
system10Nitrogen oxide sensor11Trailer module/Trailer socket12Trailer module13Trailer outlet14–15–No.Circuit16Interior mirror/Rear view
camera17Power outlet18–19Steering wheel heating20Sunblind21Heated front seats22–23–24Selective catalytic reduction
system25–26–27–28–29–30–No.Circuit31–32Active damping system/Lane
departure warning