Page 221 of 305
Driving and operating219Checking 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 222 of 305

220Driving and operatingIllustration shows 5-door hatchback.
Illustration shows Sports Tourer.
Attach 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 connecting socket.
On Sports Tourer insert cover into
rear bumper as shown in the
illustration.
Page 226 of 305
224Vehicle careVehicle 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 bonnet release lever and
return it to its original position.
Move the safety catch sideways to the left vehicle side and open the bonnet.
Secure the bonnet support.
Page 228 of 305

226Vehicle careWhen the engine oil level has
dropped to the MIN mark, top up
engine oil.
The engine oil level must not exceed
the MAX mark on the dipstick.
We recommend the use of the same
grade of engine oil that was used at
last change.Caution
Wipe off any spilled engine oil
immediately.
Caution
Overfilled engine oil must be
drained or suctioned out. If the oil
exceeds the maximum level, do
not start the vehicle and contact a
workshop.
Capacities 3 283.
Fit the cap on straight and tighten it.
Engine coolant
The factory filled coolant provides
freeze protection down to approx.
-28 °C. In cold regions with very low
temperatures, the factory filled
coolant provides frost protection
down to approx. -37 °C.Caution
Only use approved antifreeze.
Coolant and antifreeze 3 273.
Coolant level
Caution
Too low a coolant level can cause engine damage.
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
released coolant concentrate mixed
with clean tap water. If no coolant
concentrate is available, use clean
tap water. Install the cap tightly. Have
Page 229 of 305
Vehicle care227the coolant concentration checked
and have the cause of the coolant
loss remedied by a workshop.
Washer 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.
Washer fluid 3 273.
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 3 273.
Page 230 of 305

228Vehicle careVehicle battery
The vehicle battery is located in the
load compartment.
There are connecting points for jump
starting 3 263.
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.
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.
Battery discharge protection 3 140.
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.
Ensure that the battery is always replaced by the same type of battery.
The vehicle battery has to be
replaced by a workshop.
Stop-start system 3 157.
Charging the vehicle battery9 Warning
On vehicles with stop-start
system, ensure that the charging potential does not exceed 14.6 V
Page 231 of 305

Vehicle care229when using a battery charger.
Otherwise the vehicle battery may be damaged.
Jump starting 3 263.
Discharge protection
Battery voltage
When the vehicle battery voltage is running low, a warning message will
appear in the Driver Information
Centre.
When the vehicle is being driven, the
load reduction function temporarily
deactivates certain functions, e.g. the heated rear window.
The deactivated functions are
reactivated automatically as soon as
conditions permit.
Idle boost
If charging of the vehicle battery is
required due to battery condition, the
power output of the generator must
be increased. This will be achieved by
an idle boost which may be audible.
A message appears in the Driver
Information Centre.
Power outlet
The power outlets are deactivated in
the event of low vehicle battery
voltage.
Warning 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 containssulphuric 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 5 seconds. If the engine fails to start, seek the assistance of a
workshop.
Page 252 of 305

250Vehicle careThe tyre pressure information labelon the left door frame indicates the
original equipment tyres and the
correspondent tyre pressures.
The tyre pressure data refers to cold
tyres. It applies to summer and winter tyres.
Always inflate the spare tyre to the
pressure specified for full load.
The ECO tyre pressure serves to
achieve the smallest amount of fuel
consumption possible.
Make sure tyre loading setting
matches the current tyre pressure.
Tyre loading 3 251.
Incorrect tyre pressures will impair
safety, vehicle handling, comfort and fuel economy and will increase tyre
wear.
Tyre pressures differ depending on
various options.
For the correct tyre pressure value,
follow the procedure below:
● Identify the engine identifier code.Engine data 3 280.
● Identify the respective tyre. ● The tyre pressure tables show all
possible tyre combinations
3 285.
For the tyres approved for your
vehicle, refer to the EEC Certificate of Conformity provided with your vehicle
or other national registration
documents.
The driver is responsible for correct
adjustment of tyre pressure.9 Warning
If the pressure is too low, this can
result in considerable tyre warm-
up and internal damage, leading to tread separation and even to tyre
blow-out at high speeds.
9 Warning
For specific tyres the
recommended tyre pressure as
shown in the tyre pressure table may exceed the maximum tyre
pressure as indicated on the tyre.
Never exceed the maximum tyre
pressure as indicated on the tyre.
If the tyre pressure must be reduced
or increased on a vehicle with tyre
pressure monitoring system, switch
off ignition.
Temperature dependency
The tyre pressure depends on the
temperature of the tyre. During
driving, tyre temperature and
pressure increase. Tyre pressure
values provided on the tyre
information label and tyre pressure
chart are valid for cold tyres, which means at 20 °C.
The pressure increases by nearly
10 kPa for a 10 °C temperature
increase. This must be considered
when warm tyres are checked.
The tyre pressure value displayed in
the Driver Information Centre shows
the real tyre pressure. A cooled down tyre will show a decreased value,which does not indicate an air leak.