Page 137 of 237

Driving and operating135Turbo engine warm-upUpon 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.
Idle speed control
To increase the idle speed, press the switch. After a few seconds the
function will be activated.
The function will be deactivated
when:
● The clutch pedal is depressed.
● The accelerator pedal is depressed.
● Vehicle speed is above 0 km/h. ● Control indicator F, W or C
illuminate in the instrument
cluster.
To increase or decrease the fast idle
speed rate, consult a workshop.
Note
When the fast idle function is
activated, the stop-start system is
automatically deactivated.
Stop-start system 3 136.
Vehicle shutdown
Fuel cut-off system
If the vehicle runs out of fuel, the fuel
system is cut-off and must be reset
after refuelling. A corresponding
warning message may also appear in the Driver Information Centre 3 102.9
Danger
If you can smell fuel in the vehicle,
or a fuel leak is present, have thecause of this remedied
immediately by a workshop. Do
not reset the fuel cut-off system, to avoid the risk of fire.
Resetting with remote control
key / manual key
To reset the fuel cut-off system and
enable the vehicle to be driven:
1. Turn the ignition key to position 2
3 132.
2. Wait a few minutes to allow the fuel system to be reset.
3. Turn key to position 3 to start the
engine.
If the engine does not start, repeat the
procedure.
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136Driving and operatingResetting with electronic key
system
To reset the fuel cut-off system and
enable the vehicle to be driven:
1. Insert the electronic key in the card reader 3 132.
2. Press START/STOP without
depressing any pedals.
3. Wait a few minutes to allow the fuel system to be reset.
If the engine does not start, repeat the
procedure.
Electronic key system 3 24.
Power button 3 132.
Refuelling 3 160.
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 restarts the engine
automatically as soon as the clutch
pedal is depressed.
A vehicle battery sensor ensures that an Autostop is only performed if thevehicle 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.
If the below conditions are not
fulfilled, an Autostop is prohibited and
control indicator \ illuminates in the
instrument cluster 3 101.Deactivation
Deactivate the stop-start system
manually by pressing Î. LED in the
button illuminates to indicate
deactivation and a corresponding message appears in the Driver
Information Centre 3 102.
If deactivated manually, it is possible to reactivate the stop-start system by
pressing Î again; LED extinguishes
in the button and a corresponding
message appears in the Driver
Information Centre. The system is
reactivated automatically the next
time the ignition is switched on.
Vehicle messages 3 103.
Page 139 of 237

Driving and operating137Note
When the fast idle function is
activated, the stop-start system is
automatically deactivated and
cannot be reactivated by pressing
Î . LED in button illuminates to
indicate deactivation and a
corresponding message may
appear in the Driver Information
Centre 3 102.
Idle speed control 3 135.
Depending on version, if the driver's
door is opened or the driver's seat belt
is unfastened, the stop-start system is
deactivated automatically, and the
engine is switched off. Restart engine by pressing START/STOP .
Power button 3 132.
Autostop If the vehicle is at a low speed or at astandstill, activate an Autostop as
follows:
● depress the clutch pedal
● move the selector lever to neutral
● release the clutch pedalThe engine will be switched off while
the ignition stays on if the required conditions are met.
An Autostop is indicated when Ï
illuminates in the instrument cluster
3 101.
During an Autostop, heating and brake performance will be
maintained. Brake assist, however, is
not available 3 148.
Caution
The power steering assist may be
reduced during an Autostop.
If you exit the vehicle while the engine is in an Autostop, a warning chime will
sound and a message " IGNITION
OFF " is displayed in the Driver
Information Centre as a reminder that
the engine is on standby and has not
been switched off.
Conditions for an Autostop
The stop-start system checks if each
of the following conditions is fulfilled,
otherwise an Autostop will be
inhibited and control indicator \ will
illuminate in the instrument cluster:
● 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 outside temperature is not too
low or too high (e.g. below 0 °C
or above 30 °C)
Page 140 of 237

138Driving and operating● the defrosting function is notactivated
● the climate control system does not inhibit an Autostop
● the brake vacuum is sufficient
● the self-cleaning function of the diesel particle filter is not active
3 140
● the Antilock brake system (ABS) 3 147, Traction Control system
(TC) 3 149 and Electronic
Stability Program (ESP® Plus
)
3 150 ride control systems are
not actively engaged
● the vehicle has moved since the last Autostop
Otherwise an Autostop will be
inhibited.
Certain settings of the climate control
system may also inhibit an Autostop.
See " Climate control " chapter for
further information 3 118.
Immediately after motorway driving
an Autostop may be inhibited.
New vehicle running-in 3 132.Vehicle battery discharge protection
To ensure reliable engine restarts, several battery discharge protection
features are implemented as part of
the stop-start system.
Restart of the engine by the driver
Depress the clutch pedal to restart the
engine.
Note
If any gear is selected, the clutch
pedal must be fully depressed to
restart the engine.
If the engine does not restart first
time, depress clutch pedal fully again.
Alternatively, press button Î to
restart the engine while in an
Autostop.
Control indicator Ï 3 101
extinguishes in the instrument cluster when the engine is restarted.
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 vehicle battery is discharged
● the outside temperature is too low or too high (e.g. below 0 °C
or above 30 °C)
● the defrosting function is activated 3 118
● the brake vacuum is not sufficient
● the brake pedal is operated repeatedly
● the vehicle starts to move
An automatic engine restart may not
be possible if a door or the bonnet is
open.
If an electrical accessory, e.g. a
portable CD player, is connected to
the power outlet, a brief power drop
during engine restart may be
noticeable.
If the Infotainment system is active,
audio sound may briefly be reduced
or interrupted during the restart.
Page 141 of 237

Driving and operating139Fault
If a fault occurs in the stop-start
system, the LED in Î illuminates,
and a corresponding message
appears in the Driver Information
Centre 3 102 . Seek the assistance of
a workshop.
Vehicle messages 3 103.
Warning chimes 3 104.
Parking9 Warning
● Do not park the vehicle on an
easily ignitable surface. The
high temperature of the
exhaust system could ignite the
surface.
● Always apply parking brake without pressing 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.
● Switch off the engine.
● If the vehicle is on a level surface or uphill slope, engage
first gear. On an uphill slope,
turn the front wheels away from
the kerb.
If the vehicle is on a downhill
slope, engage reverse gear.
Turn the front wheels towards the kerb.
● Close the windows.
● Remove the ignition key from the ignition switch. Turn the
steering wheel until the
steering wheel lock is felt to
engage.
● Lock the vehicle by pressing e on
the remote control 3 26.
Activate the anti-theft alarm
system 3 38.
● The engine cooling fans may run
after the engine has been
switched off 3 166.
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.
Vehicle storage 3 165.
Page 142 of 237

140Driving 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
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. Autostop is not available
and fuel consumption may be higher
during this period. The emission of
smells and smoke during this process is normal.
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 be
indicated by the illumination of control
indicators F 3 98 and Z 3 98 in the
instrument cluster. Seek the
assistance of a workshop
immediately.Caution
If the cleaning process is
interrupted, there is a risk of
provoking severe engine damage.
Cleaning takes place quickest at high engine speeds and loads.
Catalytic converter
The catalytic converter reduces the
amount of harmful substances in the
exhaust gases.Caution
Fuel grades other than those listed on page 3 159, 3 210 could
damage the catalytic converter or
electronic components.
Unburnt fuel 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.
Page 143 of 237

Driving and operating141If control indicator Z flashes, the
permitted emission limits may be
exceeded. Lift your foot off the
accelerator until Z stops flashing and
is steadily illuminated. Contact a
workshop immediately.
Malfunction indicator light 3 98.
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 (DEF) into the exhaust system.
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.9 Warning
Avoid contact of your eyes or skin
with AdBlue.
In case of eye or skin contact,
rinse off with water.
Caution
Avoid contact of the paintwork with AdBlue.
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.
AdBlue level indicator
The current AdBlue percentage
remaining can be shown in the Driver
Information Centre 3 102.
Page 144 of 237

142Driving and operatingPress button on end of wiper lever
repeatedly until the 'AdBlue
percentage remaining' menu is
displayed.
Level warnings
The AdBlue consumption is approx.
3.0 litres per 1000 km and depends on the driving behaviour.
If the AdBlue level falls below a
certain value, a level warning will be
displayed in the Driver Information
Centre 3 102. Additionally, control
indicator Y illuminates continuously
together with a warning chime.
Refill the AdBlue tank as soon as
possible. Refer to "Refilling AdBlue"
below.
If AdBlue is not refilled within a certain distance, further level warnings are
displayed in the Driver Information
Centre depending on the current
AdBlue level.
Engine restarts prevented
Subsequent requests to refill AdBlue
and finally the announcement that an
engine restart will be prevented are
displayed in the Driver Information
Centre.
Note
These restrictions are a legal
requirement.
Before the prevention of an engine restart, a warning message with
0 km is displayed in the Driver
Information Centre, indicating that
after switching off the ignition an
engine restart will be prohibited.
After the prevention of an engine
start, a warning message is displayed in the Driver Information Centre
reminding the driver that AdBlue level is insufficient.To allow the engine to be restarted,
the tank should be refilled completely
or with a volume of at least ten litres
of AdBlue, depending on AdBlue
consumption.
Warning stages: level warnings,
engine restarts prevented
1. Y illuminates after ignition is
switched on with warning
message LEVEL ADBLUE LOW :
Driving is possible without any
restrictions.
Refill the AdBlue tank as soon as
possible.
2. Y illuminates during driving with
warning message TOP UP
ADBLUE :
Possible loss of engine power.
Refill the AdBlue tank as soon as
possible.
3. Y illuminates during driving with
warning message XXX KM STOP
ADD ADBLUE :
Vehicle speed may be limited to
20 km/h after switching the engine
off and on again until the range is
reduced to 0 km.