Page 412 of 506
410 Practical hintsUnlocking/locking in an emergencyUnlocking the vehicle
If you are unable to unlock the vehicle with
the SmartKey, open the driver’s door and
the trunk using the mechanical key.
1Mechanical key locking tab
2Mechanical key
Move locking tab1 in the direction of
the arrow and slide mechanical key2
out of the housing.Unlocking the driver’s door
3Unlocking
4Locking
Unlock the door with the mechanical
key. To do so, push the mechanical key
in the lock until it stops and turn it to
the left.
iUnlocking your vehicle with the me-
chanical key will trigger the anti-theft
alarm system. To cancel the alarm, do
one of the following:
Press button Œ or ‹ on the
SmartKey.
Insert the SmartKey in the starter
switch.
Press the KEYLESS-GO* start/stop
button (
page 35).
Page 413 of 506

411 Practical hints
Unlocking/locking in an emergency
Unlocking the trunk
A minimum height clearance of 5.90 ft
(1.80 m) is required to open the trunk lid.
If you are unable to unlock the trunk with
the SmartKey or KEYLESS-GO*, open the
trunk with the mechanical key.
The handle is located above the rear li-
cense plate recess.
1Unlocking in an emergency
2Handle
Insert the mechanical key into the
trunk lid lock.
Turn the mechanical key counterclock-
wise to position1 and hold it in this
position.
Pull trunk lid handle2 and lift the
trunk lid.
Locking the vehicle
If you are unable to lock the vehicle with
the SmartKey, lock it with the mechanical
key as follows:
Close the passenger doors and the
trunk.
Press the central locking switch in the
cockpit (
page 119).
Check to see whether the locking
knobs on the passenger doors are still
visible. If necessary, push them down
manually.
Slide mechanical key2 out of the
SmartKey.
Lock the driver’s door with the me-
chanical key (
page 411).
Check if the trunk is locked.
!Always make sure there is sufficient
overhead clearance.iUnlocking your vehicle with the me-
chanical key will trigger the anti-theft
alarm system. To cancel the alarm, do
one of the following:
Press buttonŒ or‹ on the
SmartKey.
Insert the SmartKey in the starter
switch.
Vehicles with KEYLESS-GO*:
Grasp the outside door handle.
Press the start/stop button.
Page 432 of 506

430 Practical hintsFlat tire
Screw air hose 4 onto the tire valve.
Insert electrical plug 3 into vehicle ci-
gar lighter socket.
Turn the SmartKey in the ignition to
position1.
or
Press the KEYLESS-GO* start/stop
button on the gear selector lever once
without depressing the brake pedal.
Press I on electric air pump switch 2.
The electric air pump should now
switch on and inflate the tire.
Inflate the tire to approx. 51 psi
(3.5 bar).
This takes about five minutes for the
collapsible tire. Air hose 4 and union
nut5 can become hot duration infla-
tion. Exercise proper caution to avoid
burning yourself when using the equip-
ment.
Press 0 on electric air pump switch 2.
Turn the SmartKey in the ignition to
position0.
or
Press KEYLESS-GO* start/stop button
on the gear selector lever twice without
depressing the brake pedal.
The electric air pump should now be
switched off.
If the tire inflation pressure is above
51 psi (3.5 bar), release excess tire in-
flation pressure using the vent screw.
Detach the electric air pump.
Stow electrical plug 3 and air hose 4
behind flap 1 and place the air pump
back in the trunk.
!Do not operate the air pump longer
than eight minutes without interrup-
tion. Otherwise it may overheat.
You may operate the air pump again af-
ter it has cooled off.
Warning!
G
Follow recommend inflation pressures.
Do not overinflate tires. Overinflating tires
can result in sudden deflation (blowout) be-
cause they are more likely to become punc-
tured or damaged by road debris, potholes,
etc.
Do not underinflate tires. Underinflated tires
wear unevenly, adversely affect handling
and fuel economy, and are more likely to fail
from being overheated.
Page 436 of 506

434 Practical hintsBatteries
Disconnecting the battery
Depress parking brake firmly or move
gear selector lever to positionP.
Turn off all electrical consumers.
Remove SmartKey from starter switch.
Vehicles with KEYLESS-GO*:
Press the start/stop button until
the engine shuts off.
Open the driver’s door.
Open the trunk.
!Never loosen or detach battery termi-
nal clamps while the engine is running
or the SmartKey is in the starter switch.
Otherwise the alternator and other
electronic components could be se-
verely damaged.
Have the battery checked regularly by
an authorized Mercedes-Benz Center.
Refer to Maintenance Booklet for main-
tenance intervals or contact your au-
thorized Mercedes-Benz Center for
further information.Warning!
G
Do not place metal objects on the battery as
this could result in a short circuit.
Use leak-proof battery only to avoid the risk
of acid burns in the event of an accident.
Warning!
G
The SBC brake system requires electrical
power to operate.
A malfunction in the vehicle’s power supply
or electrical system may impair brake sys-
tem operation and switch it into its emer-
gency operation mode. The same applies if
battery is disconnected. To brake, the driver
must then apply significantly greater brake
pedal pressure and depress the pedal much
further to obtain the expected braking ef-
fect. If necessary, apply full pressure to the
brake pedal. Brakes may only be applied to
the front wheels. Stopping distance is in-
creased! Adjust your driving style according-
ly. For more information, refer to “SBC brake
system” (
page 90).
Warning!
G
With a disconnected battery
you will no longer be able to turn the
SmartKey in the starter switch and
pressing the KEYLESS-GO* start/stop
button on the gear selector lever will
have no effect
the gear selector lever will remain
locked in positionP
Page 443 of 506

441 Practical hints
Towing the vehicle
iTo signal turns while being towed with
the hazard warning flasher in use, turn
SmartKey in starter switch to
position2 and activate the combina-
tion switch for the left or right turn sig-
nal in the usual manner – only the
selected turn signal will operate.
Upon canceling the turn signal, the haz-
ard warning flasher will operate again.
!When towing the vehicle with all wheels
on the ground, please note the follow-
ing:
With the automatic central locking acti-
vated and the SmartKey in starter
switch position2, or KEYLESS-GO*
start/stop button in position2, the ve-
hicle doors lock if the left front wheel
as well as the right rear wheel are turn-
ing at vehicle speeds of approximately
9 mph (15 km/h) or more.
Switch off the tow-away alarm
(page 95).
To prevent the vehicle door locks from
locking, deactivate the automatic cen-
tral locking (
page 118).
Towing of the vehicle should only be
done using the properly installed tow-
ing eye bolt. Never attach tow cable,
tow rope or tow rod to the vehicle chas-
sis, frame or suspension parts.
iThe selector lever will remain locked in
positionP and the SmartKey will not
turn in the starter switch if the battery
is disconnected or discharged. For
more information see “Battery”
(page 433) or “Jump starting”
(page 436).
Manual unlocking of the transmission
selector lever (
page 412).