Page 85 of 474

83 Safety and Security
Driving safety systems
For more information, see “Practical hints”
(page 337).Switching off the ESP
To improve the vehicle's traction, turn off
the ESP in driving situations where it would
be advantageous to have the drive wheels
spin and thus cut into surfaces for better
grip such as:
starting out on slippery surfaces and in
deep snow in conjunction with snow
chains
in sand or gravel
Warning!
G
The ESP cannot prevent the natural laws of
physics from acting on the vehicle, nor can
it increase the traction afforded. The ESP
cannot prevent accidents, including those
resulting from excessive speed in turns, or
hydroplaning. Only a safe, attentive, and
skillful driver can prevent accidents. The ca-
pabilities of an ESP equipped vehicle must
never be exploited in a reckless or danger-
ous manner which could jeopardize the us-
er’s safety or the safety of others.iDistronic* is switched off when ESP is
activated.iThe ESP will only function properly if
you use wheels of the recommended
tire size (
page 422).
!Because of the ESP’s automatic opera-
tion, the engine and ignition must be
shut off (SmartKey in starter switch
position0 or1 or KEYLESS-GO
start/stop button* in position0 or1)
when
the parking brake is being tested on
a brake test dynamometer
the vehicle is being towed with the
front/rear axle raised
Active braking action through the ESP
may otherwise seriously damage the
brake system.
Warning!
G
The ESP should not be switched off during
normal driving other than in the circum-
stances described below. Disabling of the
system will reduce vehicle stability in stan-
dard driving maneuvers.iDistronic* cannot be activated when
the ESP has been deactivated.
Page 87 of 474

85 Safety and Security
Driving safety systems
Four wheel electronic traction system (4MATIC) with the ESP
Models with all-wheel drive only:
The 4MATIC improves the vehicle’s ability
to use available traction, e.g. during winter
operation in mountains under snowy con-
ditions, by applying power to all four
wheels.
Warning!
G
If you see the ESP warning lamp v flash-
ing in the speedometer dial, proceed as fol-
lows:
While driving off, apply as little throttle
as possible.
While driving, ease up on the accelera-
tor.
Adapt your speed and driving style to
the prevailing road conditions.
Failure to observe these guidelines could
cause the vehicle to skid.
The ESP cannot prevent accidents resulting
from excessive speed.!Do not tow with one axle raised.
Otherwise the transfer case can be
damaged, which is not covered by the
Mercedes-Benz Limited Warranty.
!Performance testing must only be con-
ducted on a two-axle dynamometer.
Otherwise the transfer case can be
damaged, which is not covered by the
Mercedes-Benz Limited Warranty.!Because of the ESP’s automatic opera-
tion, the engine and ignition must be
shut off (SmartKey in starter switch
position0 or1 or KEYLESS-GO*
start/stop button (
page 35) in
position0 or1) when the parking
brake is being tested on a brake test
dynamometer.
Active braking action through the ESP
may otherwise seriously damage the
front or rear axle brake system.
Operational tests with the engine run-
ning can only be conducted on a
two-axle dynamometer.
Page 88 of 474
86 Safety and SecurityAnti-theft systemsImmobilizer
The immobilizer prevents unauthorized
persons from starting your vehicle.
Activating
With the SmartKey
Remove the SmartKey from the starter
switch.
The immobilizer is activated.
With KEYLESS-GO*
Turn off the engine by means of the
start/stop button (
page 35) on the
gear selector lever.
Open the driver’s door.
The immobilizer is activated.Deactivating
With the SmartKey
Insert the SmartKey in the starter
switch.
The immobilizer is deactivated.With KEYLESS-GO*
Start the engine by means of the
start/stop button (
page 35) on the
gear selector lever.
The immobilizer is deactivated.
iIn case the engine cannot be started
(yet the vehicle’s battery is charged),
the system is not operational. Contact
an authorized Mercedes-Benz Center
or call
1-800-FOR-MERCedes (in the USA), or
1-800-387-0100 (in Canada).
Page 89 of 474

87 Safety and Security
Anti-theft systems
Anti-theft alarm system
Once the alarm system has been armed, a
visual and audible alarm is triggered when
someone opens:
a door
the trunk
the hood
The alarm will stay on even if the activating
element (a door, for example) is immedi-
ately closed.The alarm system will also be triggered
when
someone attempts to raise the vehicle
the vehicle is opened with the
mechanical key
someone opens a door from the inside
if the vehicle was locked from the out-
side with the SmartKey
someone opens the trunk lid with the
emergency release buttonArming the alarm system
The indicator lamp located in the central
locking switch in on the upper part of the
front center console.
1Indicator lamp
Lock your vehicle.
The turn signal lamps flash three times
to indicate that the alarm system is ac-
tivated. The indicator lamp1 flashes
to indicate that the alarm system is
armed.
iIf the alarm stays on for more than
30 seconds, a call to the Response
Center is initiated automatically by the
by the Tele Aid system (
page 255)
provided Tele Aid service was sub-
scribed to and properly activated, and
that necessary cellular service and GPS
coverage are available.
Page 90 of 474
88 Safety and SecurityAnti-theft systemsDisarming the alarm system
Unlock your vehicle.
The turn signal lamps flash once to in-
dicate that the alarm system is deacti-
vated.Canceling the alarm
To cancel the alarm:
With the SmartKey
Insert the SmartKey in the starter
switch.
or
Press the Œ or ‹ button on the
SmartKey.
The alarm is canceled.With KEYLESS-GO*
Grasp the outside door handle.
The SmartKey with KEYLESS-GO must
be within 3 ft. (1 m) of the vehicle.
or
Press the KEYLESS-GO* start/stop
button (
page 35).
The SmartKey with KEYLESS-GO must
be inside the vehicle.
The alarm is canceled.
iIf the turn signal lamps does not flash
three times one of the following ele-
ments may not be properly closed:
a door
the trunk
the hood
Close the respective element and lock
the vehicle again.
iThe alarm system will rearm automati-
cally again after approximately 40 sec-
onds if no door was opened.
Page 92 of 474
90 Safety and SecurityAnti-theft systemsThe button is located on the upper part of
the front center console.
1Indicator lamp
2Tow-away alarm off button
Switch off the ignition and remove the
SmartKey from the starter switch.
Press button2.
The indicator lamp1 in the button
comes on briefly.
Exit the vehicle and lock it with the
SmartKey or (vehicles with
KEYLESS-GO*) the lock button at each
outside door handle or trunk lid.
iYou cannot disarm the tow-away alarm
if the ignition is switched on.
iWhen you unlock your vehicle, the
tow-away protection disarms automati-
cally.
The tow-away alarm remains disarmed
until you lock your vehicle again.
Page 94 of 474

92 Controls in detailIn the “Controls in detail” section you will
find detailed information on how to oper-
ate the equipment installed in your vehicle.
If you are already familiar with the basic
functions of your vehicle, this section will
be of particular interest to you.
To quickly familiarize yourself with the ba-
sic functions of the vehicle, refer to the
“Getting started” section of this manual.
The corresponding page numbers are giv-
en at the beginning of each segment.Locking and unlocking
For more information on locking and un-
locking, see “Getting started” (
page 32)
and (
page 58).
SmartKey
Your vehicle comes supplied with two
SmartKeys, each with remote control and
a removable mechanical key.
The locking tabs for the mechanical key
portion of the two SmartKeys are a differ-
ent color to help distinguish each
SmartKey unit.
The SmartKey provides an extended oper-
ating range. To prevent theft, however, it is
advisable to only unlock the vehicle when
you are in close proximity to it.
The SmartKey centrally locks and unlocks:
the doors
the trunk
the fuel filler flap
SmartKey with remote control1‹ Lock button
2Š Opening button for trunk
3Mechanical key locking tab
4Œ Unlock button
5Battery check lamp
6Â Panic button (
page 79)
Page 95 of 474

93 Controls in detail
Locking and unlocking
Warning!
G
When leaving the vehicle, always remove the
SmartKey from the starter switch, take it
with you, and lock the vehicle. Do not leave
children unattended in the vehicle, or with
access to an unlocked vehicle. It is possible
for children to open a locked door from the
inside, which could result in an accident
and/or serious personal injury.!To prevent possible malfunction, avoid
exposing the SmartKey to high levels of
electromagnetic radiation.
iUSA only:
This device complies with Part 15 of
the FCC Rules. Operation is subject to
the following two conditions:
This device may not cause harmful
interference, and
this device must accept any inter-
ference received, including interfer-
ence that may cause undesired
operation.
Any unauthorized modification to this
device could void the user’s authority
to operate the equipment.
iCanada only:
This device complies with RSS-210 of
Industry Canada. Operation is subject
to the following two conditions:
This device may not cause interfer-
ence, and
this device must accept any inter-
ference received, including interfer-
ence that may cause undesired
operation of the device.
Any unauthorized modification to this
device could void the user’s authority
to operate the equipment.
iYou can also open and close the power
windows (
page 209) and tilt/sliding
sunroof (
page 209) using the
SmartKey.