158Driving and operatingStarting 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 3 159.
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 3 159.
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
Driving and operating159extinguish. 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.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.
160Driving and operatingDeactivation
Deactivate the stop-start system
manually by pressing eco. The
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.
● Set the 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 lights up 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.
● The climate control system allows an Autostop.
● The brake vacuum is sufficient.
Driving and operating161● The self-cleaning function of thediesel 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 3 140.
Immediately after motorway driving
an Autostop may be inhibited.
New vehicle running-in 3 155.
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 such as auxiliary electric
heater or rear window heating are
disabled or switched 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 - 3 105.
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.
Driving and operating163Engine 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 and may
take up to 25 minutes. Typically it
needs between 7 and 12 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.
Under certain driving conditions, e.g.
short distances, the system cannot
clean itself automatically.
If the cleaning of the filter is required
and if previous driving conditions did
not enable automatic cleaning, it will
be indicated by control indicator %.
Simultaneously Diesel partic. filter is
full continue driving appears in the
Driver Information Centre.
% illuminates when diesel particle
filter is full. Start cleaning process as
soon as possible.
% flashes and a warning chime
sounds several times when diesel
particle filter has reached the
maximum filling level. Start cleaning
process immediately to avoid
damage to the engine.
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.
If additionally a message appears in
the Driver Information Centre that
cleaning is not possible, seek the
assistance of a workshop.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.
The control indicator % extinguishes
as soon as the self-cleaning
operation is complete.
170Driving and operatingthe shift is not executed. This can
cause a message in the Driver
Information Centre.
In manual mode, no automatic
shifting to a higher gear takes place
at high engine revolutions.
Gear shift indication
The symbol R with a number below it
is indicated when gearshifting is
recommended for fuel saving
reasons.
Shift indication appears only in
manual mode.
Electronic driving programmes
● Following a cold start, the operating temperature
programme increases engine
speed to quickly bring the
catalytic converter to the required
temperature.
● The automatic neutral shift function automatically shifts to
idling when the vehicle is stopped with a forward gear engaged andthe brake pedal is pressed.● When SPORT mode is engaged,
the vehicle shifts at higher engine speeds (unless cruise control is
on). SPORT mode 3 177.
● Special programmes automatically adapt the shifting
points when driving up inclines or
down hills.
● When starting off in snowy or icy conditions or on other slippery
surfaces, the electronic
transmission control selects a
higher gear automatically.
Kickdown If the accelerator pedal is pressed
down completely in automatic mode,
the transmission shifts to a lower gear
depending on engine speed.
Overheat protection
In the event of transmission-
overheating due to high outside
temperatures or sporty driving style,
the torque and the maximum speed of the engine can be temporarily
reduced.Fault
In the event of a fault a vehicle
message is displayed in the Driver
Information Centre. Vehicle
messages 3 119.
The transmission no longer shifts automatically. Continued travel is
possible with manual shifting.
Only the highest gear is available.
Depending on the fault, 2nd gear may also be available in manual mode.
Shift only when vehicle is stationary.
Have the cause of the fault remedied
by a workshop.
Interruption of power supply
In the event of an interruption of
power supply, the selector lever
cannot be moved out of the P
position. The ignition key cannot be
removed from the ignition switch.
If the vehicle battery is discharged,
start the vehicle using jump leads
3 265.
If the vehicle battery is not the cause
of the fault, release the selector lever.
1. Apply parking brake.
172Driving and operatingCaution
It is not advisable to drive with thehand resting on the selector lever.
Gear shift indication 3 106.
Stop-start system 3 159.
Drive systems
All-wheel drive
The All-wheel drive system enhances
driving characteristics and stability,
and helps to achieve the best
possible driveability regardless of
ground surface. The system is always
active and cannot be deactivated.
The torque is distributed steplessly
between the wheels of the front and rear axle, depending on the driving
conditions. Additionally the torque
between the rear wheels is distributed
depending on the surface.
For optimum system performance,
the vehicle's tyres should not have
varying degrees of wear.
If a service message is displayed in
the Driver Information Centre, the
system may have limited functionality (or be completely disabled in some
cases, i.e. the vehicle switches to
Front-wheel drive). Seek the
assistance of a workshop.
Towing the vehicle 3 266.Brakes
The brake system comprises two
independent brake circuits.
If a brake circuit fails, the vehicle can
still be braked using the other brake
circuit. However, braking effect is
achieved only when the brake pedal
is depressed firmly. Considerably
more force is needed for this. The
braking distance is extended. Seek the assistance of a workshop beforecontinuing the journey.
When the engine is not running, the
support of the brake servo unit
disappears once the brake pedal has been depressed once or twice.
Braking effect is not reduced, but
braking requires significantly greater
force. It is especially important to bear this in mind when being towed.
Control indicator R 3 105.
Antilock brake system
Antilock brake system (ABS)
prevents the wheels from locking.
Driving and operating175Functionality check
When the vehicle is not moving, the
electric parking brake might be
applied automatically. This is done to
check the system.
Fault
Failure mode of electric parking brake
is indicated by a control indicator j
and by a vehicle message which is
displayed in the Driver Information Centre. Vehicle messages 3 119.
Apply electric parking brake: pull and hold the switch m for more than
5 seconds. If control indicator m
illuminates, electric parking brake is
applied.
Release electric parking brake: push and hold the switch m for more than
2 seconds. If control indicator m
extinguishes, electric parking brake is
released.
Control indicator m flashes: electric
parking brake is not fully applied or released. When continuously
flashing, release electric parking
brake and retry applying.Brake assist
If brake pedal is depressed quickly
and forcefully, maximum brake force
is automatically applied.
Operation of brake assist might
become apparent by a pulse in the
brake pedal and a greater resistance
when depressing the brake pedal.
Maintain steady pressure on the
brake pedal as long as full braking is
required. Maximum brake force is
automatically reduced when brake
pedal is released.
Hill start assist The system helps prevent unintendedmovement when driving away on
inclines.
When releasing the foot brake after
stopping on an incline, brakes remain
on for further two seconds. Brakes
release automatically as soon as the
vehicle begins to accelerate.
The hill start assist is not active during
an Autostop.
Stop-start system 3 159.Ride control systems
Traction Control system
The Traction Control system (TC) is a component of the Electronic Stability
Control.
TC improves driving stability when
necessary, regardless of the type of
road surface or tyre grip, by
preventing the drive wheels from
spinning.
As soon as the drive wheels starts to
spin, engine output is reduced and
the wheel spinning the most is braked
individually. This considerably
improves the driving stability of the
vehicle on slippery road surfaces.
TC is operational as soon as control
indicator b extinguishes.
When TC operates b flashes.