72 Safety and SecurityOccupant safetyThe passenger front air bag will only be
deployed if:
the system, based on OCS weight sen-
sor readings, senses that the front pas-
senger seat is occupied
the 75indicator lamp in the
center console is not lit (
page 84)
the impact exceeds a preset deploy-
ment threshold
Side impact air bags, window curtain
air bags
1Side impact air bags
2Window curtain air bagThe side impact air bags1 and window
curtain air bags2 are deployed:
on the impacted side of the vehicle
in impacts exceeding a preset deploy-
ment threshold
independently of the front air bags
In addition, the window curtain air bags 2
are deployed:
in certain vehicle rollovers
The side impact air bags1 and window
curtain air bags2 are not deployed in im-
pacts which do not exceed the system’s
deployment threshold.
Seat belts
When the engine is started the seat belt
telltale< illuminates for a maximum of
6 seconds and a warning chime sounds to
remind you and your passengers to fasten
your seat belts.
If after these 6 seconds, the driver’s or the
front passenger’s seat belt (with the front
passenger seat occupied) are not fastened
with all doors closed,
and the vehicle speed does not exceed
15 mph (25 km/h), the seat belt tell-
tale < remains illuminated for as
long as either the driver’s or front pas-
senger’s seat belt is not fastened.
82 Safety and SecurityOccupant safetyWhen the OCS senses that the front passen-
ger seat occupant is classified as being up
to or less than the weight of a typical
12-month-old child in a standard child re-
straint, the 75indicator lamp will
illuminate when the engine is started and re-
main illuminated, indicating that the front
passenger front air bag is deactivated.
When the OCS senses that the front passen-
ger seat is classified as being empty, the
75indicator lamp will illuminate
when the engine is started and remain illu-
minated, indicating that the front passenger
front air bag is deactivated.
When the OCS senses that the front passen-
ger seat occupant is classified as being
heavier than the weight of a typical
12-month-old child seated in a standard
child restraint or as being a small individual
(such as a young teenager or a small adult),
the 75indicator lamp will illumi-
nate for approximately 6 seconds when the
engine is started and then, depending on oc-
cupant weight sensor readings from the
seat, remain illuminated or go out. With the
75indicator lamp illuminated, the
front passenger front air bag is deactivated.
With the 75indicator lamp out,
the front passenger front air bag is activat-
ed.
When the OCS senses that the front passen-
ger seat occupant is classified as an adult or
someone larger than a small individual, the
75indicator lamp will illuminate
for approximately 6 seconds when the en-
gine is started and then go out, indicating
that the front passenger front air bag is acti-
vated.
If the 75indicator lamp is illumi-
nated, the front passenger front air bag is
deactivated and will not be deployed.
If the 75indicator lamp is not
illuminated, the front passenger front air
bag is activated and will be deployed:
in the event of certain frontal impacts
if impact exceeds a preset deployment
threshold
independently of the side impact
air bags.
If the front passenger front air bag is
deployed, the rate of inflation will be
influenced by:
the rate of relevant vehicle deceleration
as assessed by the air bag control unit
front passenger’s weight category as
identified by the Occupant Classification
System (OCS).
91 Safety and Security
Driving safety systems
Driving safety systems
In this section you will find information on
the following driving safety systems:
ABS (A
ntilock B
rake S
ystem)
BAS (B
rake A
ssist S
ystem)
ESP
® (E
lectronic S
tability P
rogram)
Electrohydraulic brake system
4MATIC (Four Wheel Electronic
Traction System)
ABS
The Antilock Brake System (ABS) regulates
the brake pressure so that the wheels do
not lock during braking. This allows you to
maintain the ability to steer your vehicle.
The ABS is functional above a speed of
approximately 5 mph (8 km/h) indepen-
dent of road surface conditions.
On slippery road surfaces, the ABS will re-
spond even to light brake pressure.
The - indicator lamp in the instrument
cluster comes on when you switch on the
ignition. It goes out when the engine is run-
ning.
iIn winter operation, the maximum
effectiveness of the ABS, the BAS, the
ESP
®, electrohydraulic brake system
and 4MATIC is only achieved with win-
ter tires (
page 355), or snow chains
as required.
Warning!
G
The following factors increase the risk of ac-
cidents:
Excessive speed, especially in turns
Wet and slippery road surfaces
Following another vehicle too closely
The ABS, BAS, ESP
®, electrohydraulic brake
system and 4MATIC cannot reduce this risk.
Always adjust your driving style to the pre-
vailing road and weather conditions.
Warning!
G
Do not pump the brake pedal. Use firm,
steady brake pedal pressure instead. Pump-
ing the brake pedal defeats the purpose of
the ABS and significantly reduces braking
effectiveness.
93 Safety and Security
Driving safety systems
BAS
The Brake Assist System (BAS) operates in
emergency situations. If you apply the
brakes very quickly, the BAS automatically
provides full brake boost, thereby poten-
tially reducing the braking distance.
Apply continuous full braking pressure
until the emergency braking situation is
over.
The ABS will prevent the wheels from
locking.
When you release the brake pedal, the
brakes function again as normal. The BAS
is then deactivated.
ESP
®
The Electronic Stability Program (ESP
®) is
operational as soon as the engine is run-
ning and monitors the vehicle’s traction
(force of adhesive friction between the
tires and the road surface) and handling.
The ESP
® recognizes when a wheel is spin-
ning or if the vehicle starts to skid. By ap-
plying brakes to the appropriate wheel and
by limiting engine output, the ESP
® works
to stabilize the vehicle. The ESP
® is espe-
cially useful while driving off and on wet or
slippery road surfaces. The ESP® also sta-
bilizes the vehicle during braking maneu-
vers.
The ABS/ESP
® warning lamp v in the
instrument cluster flashes when the ESP
®
is engaged.
The ABS/ESP
® warning lamp v in the
instrument cluster comes on when you
switch on the ignition. It goes out when the
engine is running.
Warning!
G
If the BAS is malfunctioning, the brake sys-
tem is still functioning normally, but without
the additional brake boost available that
BAS would normally provide in an emergen-
cy braking maneuver. Therefore, the braking
distance may increase.
Warning!
G
The BAS cannot prevent the natural laws of
physics from acting on the vehicle, nor can
it increase braking efficiency beyond that
afforded by the condition of the vehicle
brakes and tires or the traction afforded.
The BAS cannot prevent accidents, includ-
ing those resulting from excessive speed in
turns, following another vehicle too closely,
or hydroplaning. Only a safe, attentive, and
skillful driver can prevent accidents. The ca-
pabilities of a BAS 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.
94 Safety and SecurityDriving safety systems
For more information, see the “Practical
hints” section (
page 373).
Warning!
G
Never switch off the ESP
® when you see the
ABS/ESP
® warning lamp v flashing in
the instrument cluster. In this case proceed
as follows:
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 result-
ing from excessive speed.
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.
!The ESP
® will only function properly if
you use wheels of the recommended
tire size (page 472).
!Vehicles without 4MATIC:
Because of the ESP’s
® automatic oper-
ation, the engine and the 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 axle raised
Active braking action through the ESP
®
may otherwise seriously damage the
brake system.
For information on vehicles with
4MATIC, see “Four wheel electronic
traction system (4MATIC) with the
ESP
®” (page 99).
95 Safety and Security
Driving safety systems
Switching off the ESP
®
To improve the vehicle’s traction, turn off
the ESP
® in driving situations where it
would be advantageous to have drive
wheels spin and thus cut into surfaces for
better grip such as:
when driving with snow chains
in deep snow
in sand or gravelWhen you switch off the ESP
®
the ESP
® does not stabilize the vehicle
the engine output is not limited, which
allows the drive wheels to spin and
thus cut into surfaces for better grip
the traction control will still brake a
spinning wheel
the ESP
® continues to operate when
you are braking
you cannot activate Distronic*The switch is located on the center con-
sole.
1ESP
® switch (off/on)
Press ESP
® switch 1 until the
ABS/ESP®warning lamp v in the
instrument cluster comes on.
The ESP
® is deactivated.
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 driving
maneuvers.
Do not switch off the ESP
® when a
Minispare or collapsible tire is mounted.
!Turn on the ESP
® immediately if the
aforementioned circumstances do not
apply anymore.
iWhen the ESP
® is switched off and one
or more drive wheels are spinning, the
ABS/ESP
® warning lamp v in the
speedometer flashes. However, the
ESP
® will then not stabilize the vehicle.
98 Safety and SecurityDriving safety systems
The electrohydraulic brake servo assis-
tance switches off automatically
approximately 2 minutes after you
turned the SmartKey in the starter
switch to position0 or removed the
SmartKey
approximately 2 minutes after you
pressed the KEYLESS-GO* start/stop
button to turn off the engine or power
supply and opened the driver’s door
(with driver’s door open, the starter
switch is set to position 0, same as
SmartKey removed from starter
switch)
approximately 20 seconds after you
locked the vehicle from outside
iIf the electrohydraulic brake system is
activated as the brake pedal is first de-
pressed, you may feel a reduced pedal
resistance and longer pedal travel than
normal. When releasing the pedal, you
may also feel the brake pedal pulsate
and you may hear a sound which is
caused by the activation of the electro-
hydraulic brake system pump. This is
normal and not an indication of a mal-
function. Pedal travel returns to normal
when you release the brake pedal and
the sound soon ceases.
If you experience the above while driv-
ing and the red brake warning lamp
(page 374) illuminates and/or warn-
ing messages appear in the instrument
cluster (
page 383), the brake system
is malfunctioning. Follow the instruc-
tions of the warning message(s) and
have the brake system checked imme-
diately.
Warning!
G
Have brake pad replacement and other work
on the electrohydraulic brake system car-
ried out by qualified technicians only. Con-
tact an authorized Mercedes-Benz Center
for further information. The electrohydraulic
brake system must be deactivated prior to
working on the system. High pressure is in-
termittently built up in the system as part of
its automatic self-test. In addition, the sys-
tem is automatically activated when the ve-
hicle is unlocked by SmartKey, when the
driver or passenger door is opened, when
the starter switch is turned to position
1,
when the brake pedal is depressed or when
the parking brake is released. Failure to de-
activate the system prior to maintenance
will cause brake pistons to extend and brake
fluid to leak, which may result in injuries
(contusions and acid burns). Extended
brake pistons may also cause injury.
100 Safety and SecurityDriving safety systemsWarning!
G
If you see the ESP
® warning lampv
flashing in the speedometer, 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 result-
ing 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 oper-
ation, the engine and the 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.
Active braking action through ESP
®
may otherwise seriously damage the
front or rear axle brake system.
Operational tests with the engine
running can only be conducted on a
two-axle dynamometer.