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Driving and operating159Starting the engine
Vehicles with ignition switch
Manual transmission: operate clutch
and brake pedal.
Automatic transmission: operate
brake pedal and move selector lever
to P or N.
Do not operate accelerator pedal.
Diesel engine: turn the key to position 2 for preheating until control
indicator ! extinguishes.
Turn key briefly to position 3 and
release: an automatic procedure operates the starter with a short delay
until the engine is running, see
Automatic Starter Control.
During an Autostop, the engine can
be started by depressing the clutch
pedal 3 160.
Vehicles with power button
Manual transmission: operate clutch
and brake pedal.
Automatic transmission: operate
brake pedal and move selector lever
to P or N.
Do not operate accelerator pedal.
Press and release Engine Start/Stop:
an automatic procedure operates the
starter with a short delay until the
engine is running, see Automatic
Starter Control.
Before restarting or to switch off the engine when vehicle is stationary,press Engine Start/Stop once more
briefly.
During an Autostop, the engine can
be started by depressing the clutch
pedal 3 160.
Emergency shut off during driving
If the engine needs to be switched off during driving in case of emergency,
press Engine Start/Stop for longer
than 2 seconds or press twice briefly
within 5 seconds.9 Danger
Switching off the engine during
driving may cause loss of power
support for brake and steering
systems. Assistance systems and
airbag systems are disabled.
Lighting and brake lights will
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160Driving and operatingextinguish. Therefore power downthe engine and ignition while
driving only when required in case of emergency.
Starting the vehicle at low
temperatures
Starting the engine without additional
heaters is possible down to -25 °С for diesel engines and -30 °C for petrol
engines. Required is an engine oil
with the correct viscosity, the correct
fuel, performed services and a
sufficiently charged vehicle battery.
With temperatures below -30 °C the
automatic transmission requires a
warming phase of approx. 5 minutes.
The selector lever must be in position P .
Automatic Starter Control This function controls the engine
starting procedure. The driver does
not need to hold the key in position 3
or to hold Engine Start/Stop pressed.
Once applied, the system will go on starting automatically until the engine
is running. Because of the checking
procedure, the engine starts running
after a short delay.
Possible reasons for a non-starting
engine:
● Clutch pedal not operated (manual transmission).
● Brake pedal not operated or selector lever not in P or N
(automatic transmission).
● Timeout occurred.
Turbo engine warm-up
Upon start-up, engine available
torque may be limited for a short time, especially when the engine
temperature is cold. The limitation is
to allow the lubrication system to fully
protect the engine.
Overrun cut-off
The fuel supply is automatically cut off
during overrun, i.e. when the vehicle
is driven with a gear engaged but accelerator pedal is released.
Depending on driving conditions, the
overrun cut-off may be deactivated.Stop-start system
The stop-start system helps to save
fuel and to reduce the exhaust
emissions. When conditions allow, it
switches off the engine as soon as the
vehicle is at a low speed or at a
standstill, e.g. at a traffic light or in a
traffic jam. It starts the engine
automatically as soon as the clutch is depressed. A battery sensor ensures
that an Autostop is only performed if
the vehicle battery is sufficiently
charged for a restart.
Activation
The stop-start system is available as soon as the engine is started, the
vehicle starts-off and the conditions
as stated below in this section are
fulfilled.
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Driving and operating161Deactivation
Deactivate the stop-start system
manually by pressing eco.
Deactivation is indicated when the
LED in the button extinguishes.
Autostop If the vehicle is at a low speed or at a
standstill, activate an Autostop as
follows:
● Depress the clutch pedal.
● Move the selector lever to neutral.
● Release the clutch pedal.
The engine will be switched off while
the ignition stays on.
An Autostop is indicated by the
needle at the AUTOSTOP position in
the tachometer. On some versions, a control indicator in the instrument
cluster illuminates when engine is in
Autostop.
During an Autostop, the heating and
brake performance will be
maintained.Caution
The steering assist can be
reduced during an Autostop.
Conditions for an Autostop
The stop-start system checks if each
of the following conditions is fulfilled.
● The stop-start system is not manually deactivated.
● The bonnet is fully closed.
● The driver's door is closed or the driver's seat belt is fastened.
● The vehicle battery is sufficiently charged and in good condition.
● The engine is warmed up.
● The engine coolant temperature is not too high.
● The engine exhaust temperature is not too high, e.g. after driving
with high engine load.
● The ambient temperature is above -5 °C.
Page 164 of 327

162Driving and operating● The climate control systemallows an Autostop.
● The brake vacuum is sufficient.
● The self-cleaning function of the diesel particle filter is not active.
● The vehicle was driven at least at
walking speed since the last Autostop.
Otherwise an Autostop will be
inhibited.
Certain settings of the climate control
system may inhibit an Autostop. See
Climate control chapter for more
details 3 141.
Immediately after motorway driving,
an Autostop may be inhibited.
New vehicle running-in 3 156.
Vehicle battery discharge protection
To ensure reliable engine restarts, several battery discharge protection
features are implemented as part of
the stop-start system.
Power saving measures
During an Autostop, several electrical
features e.g. auxiliary electric heater
or heated rear window are disabled orswitched to a power saving mode.
The fan speed of the climate control
system is reduced to save power.
Restart of the engine by the driver
Depress the clutch pedal to restart the
engine.
The engine start is indicated by the
needle at the idle speed position in
the tachometer.
If the selector lever is shifted out of
neutral before depressing the clutch
first, control indicator - illuminates
or is shown as a symbol in the Driver Information Centre.
Control indicator - 3 106.
Restart of the engine by the stop-
start system
The selector lever must be in neutral to enable an automatic restart.
If one of the following conditions occurs during an Autostop, the
engine will be restarted automatically by the stop-start system:● The stop-start system is manually deactivated.
● The bonnet is opened.
● The driver's seat belt is unfastened and the driver's door
is opened.
● The engine temperature is too low.
● The charging level of the vehicle battery is below a defined level.
● The brake vacuum is not sufficient.
● The vehicle is driven at least at walking speed.
● The climate control system requests an engine start.
● The air conditioning is manually switched on.
If the bonnet is not fully closed, a warning message is displayed in the
Driver Information Centre.
If an electrical accessory, e.g. a
portable CD player, is connected to
the power outlet, a brief power drop during the restart might be noticeable.
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Driving and operating163Parking9Warning
● Do not park the vehicle on an
easily ignitable surface. The
high temperature of the
exhaust system could ignite the
surface.
● Always apply the parking brake. Activate the manual
parking brake without pressing the release button. Apply as
firmly as possible on a downhill slope or uphill slope. Depress
brake pedal at the same time to
reduce operating force.
For vehicles with electric
parking brake, pull switch m for
approx. one second.
The electric parking brake is
applied when control indicator
m illuminates 3 106.
● Switch off the engine.
● If the vehicle is on a level surface or uphill slope, engage
first gear or set the selector
lever to position P before
removing the ignition key or
switching off ignition on
vehicles with power button. On
an uphill slope, turn the front
wheels away from the kerb.
If the vehicle is on a downhill
slope, engage reverse gear or
set the selector lever to position
P before removing the ignition
key or switching off ignition on
vehicles with power button.
Turn the front wheels towards
the kerb.
● Close the windows and the sunroof.
● Remove the ignition key from the ignition switch or switch off
ignition on vehicles with power
button. Turn the steering wheel until the steering wheel lock is
felt to engage.
For vehicles with automatic
transmission, the key can only
be removed when the selector
lever is in position P.●
Lock the vehicle with button e on
the radio remote control.
Activate the anti-theft alarm
system 3 35.
● The engine cooling fans may run
after the engine has been
switched off 3 228.Caution
After running at high engine
speeds or with high engine loads,
operate the engine briefly at a low load or run in neutral for
approx. 30 seconds before
switching off, in order to protect
the turbocharger.
Note
In the event of an accident with
airbag deployment, the engine is
turned off automatically if the vehicle
comes to a standstill within a certain time.
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164Driving and operatingEngine exhaust9Danger
Engine exhaust gases contain
poisonous carbon monoxide,
which is colourless and odourless and could be fatal if inhaled.
If exhaust gases enter the interior
of the vehicle, open the windows.
Have the cause of the fault
rectified by a workshop.
Avoid driving with an open load
compartment, otherwise exhaust
gases could enter the vehicle.
Diesel particle filter
Automatic cleaning process
The diesel particle filter system filters
harmful soot particles out of the
exhaust gases. The system includes
a self-cleaning function that runs
automatically during driving without
any notification. The filter is cleaned
by periodically burning off the soot
particles at high temperature. This
process takes place automatically
under set driving conditions and may take up to 25 minutes. Typically it
needs between seven and twelve
minutes. Autostop is not available
and fuel consumption may be higher
during this period. The emission of
smells and smoke during this process is normal.
System requires manual cleaning
process
Under certain driving conditions, e.g.
short distances, the system cannot
clean itself automatically.
If cleaning of the filter is required and
if previous driving conditions did not
enable automatic cleaning, it will beindicated by % and a warning
message in the Driver Information
Centre.
% with a warning message
illuminates when diesel particle filter
is full. Start cleaning process as soon as possible.
% with a warning message flashes
when diesel particle filter has reached
the maximum filling level. Start
cleaning process immediately to
avoid damage to the engine.
Activate manual cleaning process To activate cleaning process,
continue driving, keep engine speed
above 2000 revolutions per minute.
Shift down if necessary. Diesel
particle filter cleaning is then started.
Cleaning takes place quickest at high
engine speeds and loads.
The control indicator % extinguishes
as soon as the self-cleaning
operation is complete. Keep on
driving until self-cleaning operation is
complete.
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Driving and operating165Caution
If the cleaning process is
interrupted, there is a risk of
provoking severe engine damage.
Cleaning process not possible
If cleaning is not possible for anyreasons, Z illuminates and a warning
message appears in the Driver
Information Centre. Engine power
may be reduced. Seek the assistance
of a workshop immediately.
Catalytic converter
The catalytic converter reduces the
amount of harmful substances in the
exhaust gases.
Caution
Fuel grades other than those listed on pages 3 214, 3 284 could
damage the catalytic converter or
electronic components.
Unburnt petrol will overheat and
damage the catalytic converter.
Therefore avoid excessive use of the starter, running the fuel tank
dry and starting the engine by
pushing or towing.
In the event of misfiring, uneven
engine running, a reduction in engine performance or other unusual
problems, have the cause of the fault
rectified by a workshop as soon as
possible. In an emergency, driving
can be continued for a short period,
keeping vehicle speed and engine
speed low.
AdBlue
General information
The selective catalytic reduction
(BlueInjection) is a method to
substantially reduce the nitrogen
oxides in the exhaust emission. This
is achieved by injecting a Diesel
Exhaust Fluid into the exhaust
system. The ammonia released by
the fluid reacts with nitrous gases
(NO x) from the exhaust and turns it
into nitrogen and water.
The designation of this fluid is AdBlue
® . It is a non-toxic, non-flammable,
colourless and odourless fluid which
consists of 32% urea and 68% water.9Warning
Avoid contact of your eyes or skin
with AdBlue.
In case of eye or skin contact,
rinse off with water.
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166Driving and operatingCaution
Avoid contact of the paintwork withAdBlue.
In case of contact, rinse off with water.
AdBlue freezes at a temperature of
approx. -11 °C. As the vehicle is
equipped with an AdBlue pre-heater,
the emissions reduction at low
temperatures is ensured. The AdBlue
pre-heater works automatically.
The typical AdBlue consumption is
approx. two litres per 1000 km, but
can also be higher depending on
driving behaviour (e.g. high load or
towing).
AdBlue tank
At a remaining volume of approx. five litres, there is a liquid level switch.
Warning messages are displayed
only below that threshold. Tank
volume 3 294.
Level warnings
Depending on the calculated range of AdBlue, different messages are
displayed in the Driver Information
Centre. The messages and the
restrictions are a legal requirement.
The first possible warning is AdBlue
Range: 2400 km .
This warning will show up once briefly
with the calculated range. Driving is
possible without any restrictions.
The next warning level is entered with a range below 1750 km. The
message with the current range will always be displayed when ignition is
switched on and needs to be
confirmed 3 111 . Refill AdBlue before
entering the next warning level.
At an AdBlue range below 900 km,
the following warning messages are
alternately displayed and cannot be
dismissed:
● AdBlue Low Refill Now
● Engine Restart Prevented in 900
km .
Additionally, control indicator Y
flashes continuously.Note
In case of high AdBlue consumption, the Driver Information Centre may
display this warning without the
previous warning stages.
The last warning level is entered
when the AdBlue tank is empty.
Restart of the engine is not possible.
The following warning messages are
alternately displayed and cannot be
dismissed:
● AdBlue Empty Refill Now
● Engine Will Not Restart .
Additionally, control indicator Y
flashes continuously.
With active prevention of an engine
start, the following message will be
displayed:
Refill AdBlue To Start Vehicle .
The tank must be refilled completely
with AdBlue, otherwise restarting of the engine is not possible.