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134Driving and operatingThese functions stop working when
the driver's door is opened and the
vehicle is locked.
Note
Always take the electronic key with you when exiting the vehicle.
The electronic key being left in the
card reader is indicated by a warning
chime 3 104 and a message in the
Driver Information Centre 3 103
when the driver's door is opened.9 Danger
Never leave an electronic key
inside the vehicle when children or animals are left in the vehicle, to
avoid unintended operation of
windows, doors or engine. Risk of
fatal injury.
Fault
If the engine cannot be started, the
cause may be one of the following:
● Fault in electronic key.
● Electronic key out of reception range.
● Battery voltage too low.
● Overload of the central locking system by operating at frequentintervals, the power supply is
interrupted for a short time.
● Interference from higher-power radio waves from other sources.
Battery replacement 3 22.
Central locking system 3 26.
Electronic key system 3 24.
Starting the engine
Manual transmission: operate clutch.
Do not accelerate.
Diesel engines: turn the key to
position 2 for preheating until control
indicator ! extinguishes in the
instrument cluster 3 100.
Turn key to position 3 and release.
The increased engine speed
automatically returns to normal idling
speed as the engine temperature
rises.
Start attempts should not last longer
than 15 seconds. If engine does not
start, wait 15 seconds before
repeating starting procedure. If
necessary, depress accelerator
before repeating starting procedure.
Before restarting or to switch off the
engine, turn key back to 0.
During an Autostop, the engine can
be started by depressing the clutch
pedal.
Stop-start system 3 136.
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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.
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Vehicle care173disconnecting the main vehicle
battery or before jump starting the vehicle.
The terminals are designed for
additional electrical consumers up to
a maximum of 50 A.
Jump starting 3 197.
Diesel fuel filter The diesel fuel filter is accessible from the underside of the vehicle.
Drain filter of residual water at every
engine oil change.
Place a container underneath the
filter housing. Loosen the knurled
screw on the lower part of the filter by approx. one turn, to drain off the
water.
The filter is drained as soon as water-
free diesel fuel emerges. Retighten
the screw.
Check diesel fuel filter at shorter
intervals if the vehicle is subjected to
extreme operating conditions.
Diesel fuel system bleeding
If the fuel tank has been run dry, it will be necessary to air vent or bleed the
diesel fuel system.
Refuel then proceed as follows:With ignition key
● Switch on the ignition (key to position 2) for five seconds at a
time.
● Switch off ignition (key to position
1 ) for three seconds.
● Repeat this process multiple times.
● Start the engine (key to position 3) then switch off (key to position
0 ).
Ignition switch positions 3 132.
Page 186 of 237

184Vehicle careNo.Circuit1Battery backup (with electronic
key system)2Adaptations3Adaptations4Vehicle battery (with electronic
key system)5Additional heating and ventila‐
tion / Air conditioning system6Supplementary heating and
ventilation system7Electric exterior mirrors / Addi‐
tional adaptations8Heated exterior mirrors9Radio / Multimedia / Electric
exterior mirrors / Diagnostic
socket10Multimedia / Trailer hitch11Courtesy lights / Battery
discharge protectionNo.Circuit12Right-hand high beam / Left-
hand low beam / Sidelights /
Right-hand daytime running
light13Hazard warning flashers / Turn
and lane-change signals14Central locking15Left-hand high beam / Right-
hand low beam / Tail lights /
Left-hand daytime running light16Front fog lights / Rear fog lights /
Number plate lighting17Alarm / Horn / Lighting / Wiper18Instrument cluster19Heating and ventilation system20Rear window wiper / Wind‐
screen washer pump / Horn21General battery22Reversing lights23Brake switchNo.Circuit24Fuel injection / Starter25Airbag / Steering column lock26Passenger power window27Power steering28Brake lights29Battery backup (with electronic
key system)30Service display31Cigarette lighter / Power outlet32Heating and ventilation system33Brake lights / ABS / Immobiliser34Interior lighting / Air conditioning35Starting with electronic key
system36Rear window wiper37Warning chimes38Load compartment power outlet39Driver power window