Unlocking the driver's door (mechan-
ical key)
If the vehicle can no longer be unlocked with
the SmartKey, use the mechanical key.
XTake the mechanical key out of the Smart-
Key (
Ypage 92).
XInsert the mechanical key into the lock of
the driver's door as far as it will go.
XTurn the mechanical key counter-clockwise
to position1.
The door is unlocked.
XTurn the mechanical key back and remove
it.
XInsert the mechanical key into the Smart-
Key.
If you use the mechanical key to unlock and
open the driver's door, the anti-theft alarm
system will be triggered (
Ypage 87).
Locking the vehicle (mechanical key)
If the vehicle can no longer be locked with the
SmartKey, use the mechanical key.
XOpen the driver's door.
XClose the front-passenger door, the rear
doors and the trunk lid/tailgate.
XPress the locking button (Ypage 95).
XCheck whether the locking knobs on the
front-passenger door and the rear doors
are still visible. Press down the locking
knobs by hand, if necessary.
XClose the driver's door.
XTake the mechanical key out of the Smart-
Key (
Ypage 92).
XInsert the mechanical key into the lock of
the driver's door as far as it will go.
XTurn the mechanical key clockwise to posi-
tion 1.
The door is unlocked.
XTurn the mechanical key back and remove
it.
XMake sure that the doors and the trunk lid/
tailgate are locked.
XInsert the mechanical key into the Smart-
Key.
Trunk/cargo compartment
Important safety notes
GWARNING
Combustion engines emit poisonous exhaust
gases such as carbon monoxide. Exhaust
gases can enter the vehicle interior if the
trunk lid/tailgate is open when the engine is
running, especially if the vehicle is in motion.
There is a risk of poisoning.
Always switch off the engine before opening
the trunk lid/tailgate. Never drive with the
trunk lid/tailgate open.
!The trunk lid/tailgate swings upwards
and to the rear when opened. Therefore,
make sure that there is sufficient clearance
above and behind the trunk lid/tailgate.
96Trunk/cargo compartment
Opening and closing
Useful information
i
This Operator's Manual describes all
models and all standard and optional equip-
ment of your vehicle available at the time of
publication of the Operator's Manual.
Country-specific differences are possible.
Please note that your vehicle may not be
equipped with all features described. This
also applies to safety-related systems and
functions.
iRead the information on qualified special-
ist workshops (
Ypage 31).
Correct driver's seat position
GWARNING
You could lose control of your vehicle if you do the following while driving:
Radjust the driver's seat, head restraint,
steering wheel or mirrors
Rfasten the seat belt
There is a risk of an accident.
Adjust the driver's seat, head restraint, steer-
ing wheel and mirror and fasten your seat belt before starting the engine.
XObserve the safety guidelines on seat
adjustment (
Ypage 115).
XMake sure that seat =is adjusted prop-
erly.
Electrical seat adjustment (
Ypage 116)
When adjusting the seat, make sure that:
Ryou are as far away from the driver's air bag
as possible
Ryou are sitting in a normal upright position
Ryou can fasten the seat belt properly
Ryou have moved the backrest to an almost
vertical position
Ryou have set the seat cushion angle so that
your thighs are gently supported
Ryou can depress the pedals properly
XCheck whether the head restraint is adjus-
ted properly.
When doing so, make sure that you have
adjusted the head restraint so that the back
of your head is supported at eye level by the
center of the head restraint.
XObserve the safety guidelines on steering
wheel adjustment (
Ypage 117).
XMake sure that steering wheel :is adjus-
ted properly.
114Correct driver's seat position
Seats, steering wheel and mirrors
Adjusting the steering wheel electrically
(
Ypage 117)
When adjusting the steering wheel, make
sure that:
Ryou can hold the steering wheel with your
arms slightly bent
Ryou can move your legs freely
Ryou can see all the displays in the instru-
ment cluster clearly
XObserve the safety guidelines for seat belts
(
Ypage 50).
XCheck whether you have fastened seat
belt ;properly (
Ypage 52).
The seat belt should:
Rfit snugly across your body
Rbe routed across the middle of your shoul-
der
Rbe routed in your pelvic area across the hip
joints
XBefore starting off, adjust the rear-view mir-
ror and the exterior mirrors in such a way
that you have a good view of road and traf-
fic conditions (
Ypage 117).
XVehicles with a memory function: save
the seat, steering wheel and exterior mirror
settings with the memory function
(
Ypage 117).
Seats
Important safety notes
GWARNING
Children could become trapped if they adjust
the seats, particularly when unattended.
There is a risk of injury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children unsupervised in the vehicle.
The seats can still be adjusted when there is
no SmartKey in the ignition lock.
GWARNING
If the head restraints are not installed or not
adjusted correctly, they cannot provide pro-
tection as intended. There is an increased risk
of injury in the head and neck area, e.g. in the event of an accident or when braking.
Always drive with the head restraints instal-
led. Before driving off, make sure for every
vehicle occupant that the center of the head
restraint supports the back of the head at
about eye level.
Observe the safety notes on "Air bags"
(
Ypage 54) and "Children in the Vehicle"
(
Ypage 68).
GWARNING
You could lose control of your vehicle if you do the following while driving:
Radjust the driver's seat, head restraint,
steering wheel or mirrors
Rfasten the seat belt
There is a risk of an accident.
Adjust the driver's seat, head restraint, steer-
ing wheel and mirror and fasten your seat belt before starting the engine.
GWARNING
If you adjust the seat height carelessly, you or
other vehicle occupants could be trapped and
thereby injured. Children in particular could
accidentally press the electrical seat adjust-
ment buttons and become trapped. There is a
risk of injury.
While moving the seats, make sure that your
hands or other body parts do not get under the
lever assembly of the seat adjustment sys-
tem.
GWARNING
When you adjust a seat, you or other vehicle
occupants could become trapped, e.g. on the seat guide rail. There is a risk of injury.
Make sure when adjusting a seat that no one
has any body parts in the sweep of the seat.
Seats115
Seats, steering wheel and mirrors
Z
iThe SmartKey can be turned in the igni-
tion lock even if it is not the correct Smart- Key for the vehicle. The ignition is not
switched on. The engine cannot be started.
KEYLESS-GO
General notes
Vehicles with KEYLESS-GO are equipped with
SmartKeys featuring the integrated KEYLESS-GO function and a detachable Start/Stop but-
ton.
The Start/Stop button must be inserted in the
ignition lock and the SmartKey must be in the vehicle.
When you insert the Start/Stop button into
the ignition lock, the system needs approx-
imately two seconds recognition time. You
can then use the Start/Stop button.
Pressing the Start/Stop button several times
in succession corresponds to the different
key positions in the ignition lock. This is only
the case if you are not depressing the brake
pedal.
If you depress the brake pedal and press the
Start/Stop button, the engine starts immedi-
ately.
A check which periodically establishes a radio
connection between the vehicle and the
SmartKey determines whether a valid Smart-
Key is in the vehicle. This occurs, for example,
when starting the engine.
To start the vehicle without actively using the
SmartKey:
Rthe Start/Stop button must be inserted in
the ignition lock.
Rthe SmartKey must be in the vehicle.
Rthe vehicle must not be locked with the
SmartKey or KEYLESS-GO (
Ypage 91).
Do not keep the KEYLESS-GO key:
Rwith electronic devices, e.g. a mobile
phone or another SmartKey.
Rwith metallic objects, e.g. coins or metal
foil.
Rinside metallic objects, e.g. a metal case. This can affect the functionality of KEYLESS-
GO.
If you lock the vehicle with the SmartKey's
remote control or with KEYLESS-GO, after a
short time:
Ryou will not be able to switch on the ignition
with the Start/Stop button.
Ryou will not be able to start the engine with
the Start/Stop button until the vehicle is
unlocked again.
If you lock the vehicle centrally using the but-
ton on the front door (
Ypage 95), you can
continue to start the engine with the Start/
Stop button.
The engine can be switched off while the vehi-
cle is in motion by pressing and holding the
Start/Stop button for three seconds. This
function operat
es independently of the ECO
start/stop automatic engine switch-off func-
tion.
Key positions with KEYLESS-GO
:Start/Stop button
;Ignition lock
As soon as the ignition is switched on, all the
indicator lamps in the instrument cluster light
up. Further information on situations where
an indicator lamp either fails to go out after
starting the engine or lights up while driving
(
Ypage 204).
If Start/Stop button :has not yet been
pressed, this corresponds to the key being
removed from the ignition.
138Driving
Driving and parking
XTo switch on the power supply:press
Start/Stop button :once.
The power supply is switched on. You can
now activate the windshield wipers, for
example.
The power supply is switched off again if:
Rthe driver's door is opened and
Ryou press Start/Stop button :twice when
in this position
XTo switch on the ignition: press Start/
Stop button :twice.
The ignition is switched on.
The ignition is switched off when:
Rthe driver's door is opened and
Ryou press Start/Stop button :twice when
in this position
Removing the Start/Stop button
You can remove the Start/Stop button from
the ignition lock and start the vehicle as nor-
mal using the SmartKey.
It is only possible to switch between Start/
Stop button mode and SmartKey operation
when the transmission is in position P.
XRemove Start/Stop button:from ignition
lock ;.
You do not have to remove the Start/Stop
button from the ignition lock when you leave
the vehicle. You should, however, always take
the SmartKey with you when leaving the vehi-
cle. As long as the SmartKey is in the vehicle:
Rthe vehicle can be started using the Start/
Stop button
Rthe electrically powered equipment can be
operated
Starting the engine
Important safety notes
GWARNING
If children are left unsupervised in the vehicle,
they could:
Ropen the doors, thus endangering other
people or road users.
Rget out and disrupt traffic.
Roperate the vehicle's equipment.
Additionally, children could set the vehicle in
motion if, for example, they:
Rrelease the parking brake.
Rshifting the automatic transmission out of
park position P
RStart the engine.
There is a risk of an accident and injury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children or animals unattended in the
vehicle. Always keep the SmartKey out of
reach of children.
GWARNING
Combustion engines emit poisonous exhaust
gases such as carbon monoxide. Inhaling
these exhaust gases leads to poisoning. There
is a risk of fatal injury. Therefore never leave
the engine running in enclosed spaces with-
out sufficient ventilation.
GWARNING
Flammable materials introduced through
environmental influence or by animals can
ignite if in contact with the exhaust system or
parts of the engine that heat up. There is a risk
of fire.
Carry out regular checks to make sure that
there are no flammable foreign materials in
the engine compartment or in the exhaust
system.
!Do not depress the accelerator when
starting the engine.
Driving139
Driving an d parking
Z
Problems with fuel and the fuel tank
This section provides descriptions of and solutions to safety-relevant problems. Descriptions
of and solutions to further problems can be found in the Digital Operator's Manual.
ProblemPossible causes/consequences and MSolutions
Fuel is leaking from the
vehicle.GWARNING
The fuel line or the fuel tank is faulty.
Risk of explosion or fire.
XApply the electric parking brake.
XSwitch off the engine.
XRemove the SmartKey from the ignition lock.
or, on vehicles with KEYLESS‑GO:
XOpen the driver's door.
The on-board electronics now have status 0. This is the same as
the SmartKey having been removed.
XDo not restart the engine under any circumstances.
XConsult a qualified specialist workshop.
DEF (BlueTEC vehicles only)
Important notes on use
To function properly, BlueTEC exhaust gas
aftertreatment must be operated with the
reducing agent DEF. Adding DEF is one of the
tasks performed during maintenance. Under
normal operating conditions, a tank of DEF
lasts until the next service due date.
When the supply of DEF is almost used up, the
Check
AdditiveSeeOperator'sManual
message is shown in the multifunction dis-
play.
When the DEF supply drops to a minimum, the
Remaining Starts: 16
message is shown
in the multifunction display.
If the Remaining Starts: 16
message
appears in the multifunction display, you can
start the engine another 16 times. If DEF is
not refilled, you will subsequently be unable
to start the engine.
XAdd at least 1 gal (3.8 l)of DEF.
XSwitch on the ignition for at least 60 sec-
onds.
XStart the engine.
iHave the DEF tank refilled at a qualified
specialist workshop.
Use the special DEF refill bottle when adding
DEF between maintenance intervals. Contact
an authorized Mercedes-Benz Center with
any questions or, if necessary, contact Road-
side Assistance (
Ypage 29).
If the outside temperature is below 12 ‡
(Ò11 †) it may be difficult to top up. If DEF is frozen and there is an active warning indica-
tor, it may not be possible to add DEF. Park
the vehicle in a warmer place, e.g. in a garage,
until DEF has become fluid again. It will then
be possible to add DEF again. Alternatively,
have the DEF tank refilled at a qualified spe-
cialist workshop.
Further information about BlueTEC exhaust
gas aftertreatment and DEF is available at any
authorized Mercedes-Benz Center.
Refueling149
Driving and parking
Z
Under the following circumstances, the rear
view camera will not function, or will function
in a limited manner:
Rif the trunk lid or tailgate is open
Rin heavy rain, snow or fog
Rat night or in very dark places
Rif the camera is exposed to very bright light
Rif the area is lit by fluorescent bulbs or LED
lighting (the display may flicker)
Rif there is a sudden change in temperature,
e.g. when driving into a heated garage in
winter
Rif the camera lens is dirty or obstructed.
Observe the notes on cleaning
(
Ypage 268)
Rif the rear of your vehicle is damaged. In this
event, have the camera position and setting
checked at a qualified specialist workshop
The field of vision and other functions of the
rear view camera may be restricted due to
additional accessories on the rear of the vehi-
cle (e.g. license plate holder, bicycle rack).
On vehicles with height-adjustable chassis,
leaving the standard height can result in inac-
curacies in the guide lines, depending on
technical conditions.
iThe rear view camera is protected from
raindrops and dust by means of a flap.
When the rear view camera is activated,
this flap opens.
The flap closes again when:
Ryou have finished the maneuvering proc-
ess
Ryou switch off the engine
Ryou open the trunk
Observe the notes on cleaning
(
Ypage 268).
For technical reasons, the flap may remain
open briefly after the rear view camera has
been deactivated.
!Objects not at ground level may appear to
be further away than they actually are, e.g.:
Rthe bumper of a parked vehicle
Rthe drawbar of a trailer
Rthe ball coupling of a trailer tow hitch
Rthe rear section of an HGV
Ra slanted post
Use the guidelines only for orientation.
Approach objects no further than the bot-
tom-most guideline.
The rear view camera may show a distorted
view of obstacles, show them incorrectly or
not at all. The rear view camera does not show
objects in the following positions:
Rvery close to the rear bumper
Runder the rear bumper
Rin the area immediately above the tailgate
handle
Activating/deactivating the rear view
camera
XTo activate: make sure that the SmartKey
is in position 2in the ignition lock.
XMake sure that the Activation by R
gearfunction is selected in Audio 20 or
COMAND, see the Digital Operator's Man-
ual.
XEngage reverse gear.
The rear view camera flap opens. The area
behind the vehicle is shown with guide lines
in the Audio 20 or COMAND display.
The image from the rear view camera is
available throughout the maneuvering
process.
To deactivate: the rear view camera deacti-
vates if you shift the transmission to Por after
driving forwards a short distance.
172Driving systems
Driving and parking
Display messagesPossible causes/consequences andMSolutions
XWait for aperiod of at leas t60 seconds until th enecessar ysys-
te m checks hav ebeen completed.
XMak esur ethat th edisplay message sdo no tappea rin th emul-
tifunction display.
If these condition sare fulfilled ,th efront-passenger seat can be
occupied again .Whether th ePASSENGER AI RBA GOF Findicato r
lamp remain slit or goe sout depend son how OCS classifie sth e
occupant .
If th econdition sare no tfulfilled ,th esystem is no toperating cor-
rectly.
XVisit aqualified specialist workshop immediately.
Observ eth eadditional information on OCS (
Ypage 58).
Engine
Display messagesPossible causes/consequences and MSolutions
?
CoolantToo Hot
Sto pVehicl eTur n
Engine Off
The coolan tis to ohot .
A warnin gtone also sounds.
GWARNIN G
Do notdrive when your engin eis overheated. This can caus esom e
fluids whic hmay hav eleaked into th eengin ecompartmen tto
catch fire.
Steam from th eoverheated engin ecan also caus eserious burn s
whic hcan occur jus tby openin gth ehood.
There is aris kof injury.
XPull ove rand stop th evehicl esafely and switch of fth eengine,
payin gattention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 151).
XWait until th eengin ehas cooled down .
XMakesur ethat th eair supply to th eengin eradiato ris no t
blocked, e.g. by snow, slus hor ice .
XDo no tstart th eengin eagain until th edisplay message goe sout
and th ecoolan ttemperature is belo w24 8 ‡ (120†). Other -
wise ,th eengin ecould be damaged.
XPay attention to th ecoolan ttemperature display.
XIf th etemperature increase sagain ,visit aqualified specialist
workshop immediately.
Under normal operating condition sand wit hth especified coolan t
level, th ecoolan ttemperature may ris eto 24 8 ‡(120†).
Display messages19 9
On-board computer and displays
Z