55 Safety and Security
Occupant safety
Emergency tensioning device (ETD),
seat belt force limiter
The seat belts for the front and rear outer
seats are equipped with emergency ten-
sioning devices and seat belt force limit-
ers.
The ETD is designed to activate in the
following cases:
in frontal or rear-end impacts exceed-
ing the system deployment threshold
in certain vehicle rollovers
if the restraint systems are operational
and functioning correctly,
see=indicator lamp (
page 607)
In an impact, emergency tensioning
devices remove slack from the seat belts in
such a way that the seat belts fit more
snugly against the body. Seat belt force limiters, when activated, are employed to
help reduce the peak force exerted by the
seat belts on occupants during a crash.
Automatic comfort-fit feature seat belt
An automatic comfort-fit feature for the
front seats and for the rear outer seats*
(only for vehicles with rear power seat*)
reduces the retracting force of the seat
belts when they are in normal use.
Active head restraints
The active head restraints are intended to
offer the driver and front passenger in-
creased protection from whiplash type in-
juries. In the event of a rear-end collision,
the active head restraints on the driver’s
and front passenger’s seats are designed
to move forward in the direction of travel,
providing the head with increased support
earlier on in the collision sequence. The ac-
tive head restraints move forward whether
the seat is occupied or not.
iThe ETDs for the front seats will only acti-
vate if the front seat belt is fastened (latch plate
properly inserted into buckle).
The ETDs for the rear outer seats will activate
with or without the respective seat belt fastened.
Warning!G
A pyrotechnic emergency tensioning device
(ETD) that was activated must be replaced.
When disposing of the pyrotechnic emer-
gency tensioning device, our safety instruc-
tions must be followed. These are available
at any authorized Mercedes-Benz Center.
PRE-SAFE
® has electrically operated
reversible pre-tensioners that do not require
replacement after activation.
Warning!G
Do not attach any objects (e.g. hangers) to
the head restraint posts. Otherwise, the ac-
tive head restraints may not function prop-
erly or offer the degree of protection they
were designed for in the event of an acci-
dent.
56 Safety and Security
Occupant safety
If the active head restraints have been trig-
gered in an accident, the active head re-
straints must be reset. Otherwise, the
active head restraints cannot offer any ad-
ditional protection in the event of another
rear-end collision.
For information on resetting the activated
active head restraints, see “Resetting acti-
vated head restraints” (
page 675).
You cannot remove the active head re-
straint on the driver’s and front passen-
ger’s seats.
For removal contact an authorized
Mercedes-Benz Center.
For information on head restraint adjust-
ment, see “Head restraints” (
page 353).Preventive occupant safety
(PRE-SAFE®)
Your vehicle automatically takes preven-
tive measures to better protect the occu-
pants in the following hazardous
situations.
Warning!G
Only use seat or head restraint covers which
have been tested and approved by
Mercedes-Benz for your vehicle model.
Using other seat or head restraint covers
may interfere with or prevent the activation
of the active head restraints.
Contact an authorized Mercedes-Benz Cen-
ter for availability.
Warning!G
For your protection, drive only with properly
positioned head restraints.
Adjust head restraint so that it is as close to
the head as possible and the center of the
head restraint supports the back of the head
at eye level. This will reduce the potential for
injury to the head and neck in the event of
an accident or similar situation.
Do not drive the vehicle without the seat
head restraints. Head restraints are intend-
ed to help reduce injuries during an acci-
dent.
Warning!G
The PRE-SAFE® system is intended to re-
duce the effects of an accident on properly
seat-belted vehicle occupants. Despite
having the PRE-SAFE
® system in your vehi-
cle, the possibility of injuries occurring as a
result of an accident cannot be eliminated.
Therefore, you should always drive carefully
and adjust your driving to the prevailing
road, weather, and traffic conditions.
60 Safety and Security
Occupant safety
The infant or child restraint must be properly
secured with the vehicle’s seat belt, the seat
belt and top tether strap, or lower anchors
and top tether strap, fully in accordance
with the child seat manufacturer’s
instructions.
Occupants, especially children, should al-
ways sit as upright as possible, properly use
the seat belts and use an appropriately sized
infant restraint, toddler restraint, or booster
seat recommended for the
Children can be killed or seriously injured by
an inflating air bag. Note the following im-
portant information when circumstances
require you to place a child in the front
passenger seat:
Your vehicle is equipped with air bag
technology designed to turn off the front
passenger front air bag in your vehicle
when the OCS senses the weight of a
typical 12-month-old child or less along
with the weight of a standard
appropriate child restraint on the front
passenger seat.
A child in a rear-facing child restraint on
the front passenger seat will be serious-
ly injured or even killed if the front
passenger front air bag inflates in a
collision which could occur under some
circumstances, even with the air bag
technology installed in your vehicle. The
only means to completely eliminate this
risk is to never place a child in a rear-fac-
ing child restraint in the front seat. We
therefore strongly recommend that you
always place a child in a rear-facing
child restraint in the back seat.
If you must install a rear-facing child
restraint on the front passenger seat be-
cause circumstances require you to do
so, make sure that the 59
indicator lamp is illuminated, indicating
that the front passenger front air bag is
deactivated. Should the
59indicator lamp not illu-
minate or go out while the restraint is in-
stalled, please check installation.
Periodically check the 59
indicator lamp while driving to make
sure the lamp is illuminated. If the
59indicator lamp goes out
or remains out, do not transport a child
on the front passenger seat until the
system has been repaired.
A child in a rear-facing child restraint on
the front passenger seat will be serious-
ly injured or even killed if the front pas-
senger front air bag inflates.
If you have to place a child in a for-
ward-facing child restraint on the front
passenger seat, move the seat as far
back as possible, use the proper child
restraint recommended for the age, size
and weight of the child, and secure child
restraint with the vehicle’s seat belt ac-
cording to the child seat manufacturer’s
instructions. For children larger than the
typical 12-month-old child, the front
passenger front air bag may or may not
be activated (
page 48).
66 Safety and Security
Driving safety systems
This section contains information about
Adaptive Brake Lights as well as the follow-
ing driving safety systems:
ABS (Antilock Brake System)
Adaptive Brake
BAS (Brake Assist System)
BAS Plus* (Brake Assist System Plus)
EBP (Electronic Brake Proportioning)
ESP® (Electronic Stability Program)
4MATIC (Four Wheel Electronic
Traction System)
PRE-SAFE® Brake* (Preventive Occu-
pant Safe
ty Brake)
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 ap-
proximately 5 mph (8 km/h) independent
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 (
page 28) comes on when you
switch on the ignition (
page 344). It goes
out when the engine is running.
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 driving safety systems described in this
section cannot reduce these risks or pre-
vent the natural laws of physics from acting
on the vehicle.
Always adapt your driving style to the pre-
vailing road and weather conditions and
keep a safe distance to other road users and
objects on the street.
iIn winter operation, the maximum effective-
ness of the ABS, Adaptive Brake, BAS,
BAS Plus*, EBP, ESP
® and 4MATIC is only
achieved with winter tires (
page 580), or snow
chains as required.
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.
67 Safety and Security
Driving safety systems
Braking
At the instant one of the wheels is about to
lock up, a slight pulsation can be felt in the
brake pedal, indicating that the ABS is in
the regulating mode.
Keep firm and steady pressure on the
brake pedal while experiencing the pul-
sation.
Continuous, steady brake pedal pressure
yields the advantages provided by the ABS,
namely braking power and the ability to
steer the vehicle.
The pulsating brake pedal can be an indica-
tion of hazardous road conditions and
functions as a reminder to take extra care
while driving.
Emergency brake maneuver
Keep continuous full pressure on the
brake pedal.For more information, see “Practical hints”
(
page 598).
Adaptive Brake
Adaptive Brake provides a high level of
braking safety as well as increased braking
comfort. It is coupled with ABS, ESP
® and
BAS. Adaptive Brake takes driver and vehi-
cle characteristics into consideration, thus
achieving an optimal braking effect.
Warning!G
When the ABS is malfunctioning, the BAS,
BAS Plus* and ESP® are also switched off.
When the ABS is malfunctioning, the wheels
may lock during hard braking, reducing
steering capability and extending the brak-
ing distance.
Warning!G
The ABS cannot prevent the natural laws of
physics from acting on the vehicle, nor can
it increase braking or steering efficiency
beyond that afforded by the condition of the
vehicle brakes and tires or the traction
afforded. The ABS cannot prevent acci-
dents, including those resulting from exces-
sive speed in turns, following another
vehicle too closely, or hydroplaning.
Only a safe, attentive, and skillful driver can
prevent accidents.
The capabilities of an ABS equipped vehicle
must never be exploited in a reckless or dan-
gerous manner which could jeopardize the
user’s safety or the safety of others.
69 Safety and Security
Driving safety systems
BAS Plus*
The Brake Assist System Plus (BAS Plus)
operates in emergency braking situations
and uses radar sensors* to assess the traf-
fic situation. BAS Plus assists you in brak-
ing at speeds above approximately 20 mph
(30 km/h).
When travelling in Canada in a vehicle not
registered in Canada, you must switch off
the radar sensor system* (
page 282).
Canadian law does not permit the use of
the radar sensor system* (
page 282) for
vehicles from outside of Canada. When you
switch off the radar sensor system*, the
following functions are deactivated:
BAS Plus
DISTRONIC Plus* (page 424)
Park Assist* (page 448)
PRE-SAFE® Brake* (page 76)BAS Plus detects obstacles that are in your
driving path for a sufficient period of time
to permit the system to recognize these
obstacles. If you approach the detected
obstacle quickly, BAS Plus calculates the
level of brake power boost appropriate for
the circumstance to supply when the driv-
er applies the brakes.
iUSA only:
This device has been approved by the FCC as a
“Vehicular Radar System”. The radar sensor is
intended for use in an automotive radar system
only. Removal, tampering, or altering of the de-
vice will void any warranties, and is not permitted
by the FCC. Do not tamper with, alter, or use in
any non-approved way.
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:
(1) This device may not cause interference, and
(2) this device must accept any interference re-
ceived, including interference that may
cause undesired operation of the device.
Removal, tampering, or altering of the device will
void any warranties, and is not permitted. Do not
tamper with, alter, or use in any non-approved
way.
Any unauthorized modification to this device
could void the user’s authority to operate the
equipment.
Warning!G
BAS Plus is a convenience system designed
to assist the driver during vehicle operation.
The responsibility for the vehicle speed and
the distance to the vehicle ahead, including
most importantly brake operation to assure
safe stopping distance, always remains with
the driver.
Always pay attention to traffic conditions
even while BAS Plus is switched on. Other-
wise, you may not be able to recognize
dangerous situations until it is too late and
could cause an accident resulting in person-
al or fatal injury to you or others.
70 Safety and Security
Driving safety systems
When you step quickly on the brake pedal
in an emergency braking situation,
BAS Plus automatically regulates the
brake power boost to a level that is suit-
able for the traffic situation.
If BAS Plus requires a particularly high
brake power boost, PRE-SAFE
® is activat-
ed at the same time.
Keep constant pressure on the brake
pedal until the emergency braking situ-
ation is over.
During this process, ABS prevents the
wheels from locking up.
The brakes will resume normal operation
after
the brake pedal is released
no obstacles are detected in your path
the system no longer senses a risk of a
collision
BAS Plus is deactivated.BAS Plus can react to stationary obstacles
such as standing or parked vehicles at
road speeds of up to approximately
40 mph (70 km/h).
BAS Plus can only assist you when the
radar sensors are switched on and func-
tional. You can check whether the sensors
are active by switching on DISTRONIC
Plus* (
page 424) or using the “Radar
sensor” menu (
page 282) in the instru-
ment cluster control system.
After a hard collision or damage to the
front of the vehicle from an accident, have
the adjustment and operation of the radar
sensors checked by an authorized
Mercedes-Benz Center.
If BAS Plus is not available due to a radar
sensor malfunction, the braking system
will continue to function normally with full
brake boost and full standard BAS
function.
Warning!G
BAS Plus will only respond with brake assis-
tance if it has clearly detected an object. De-
tection can be impeded by
dirty or covered sensors
snowfall or heavy rain
disturbance from other radar sources
strong radar reflection such as in park-
ing garages
BAS Plus uses radar signals that are not re-
flected well by narrow objects and absorp-
tive materials. For this reason BAS Plus will
not react to
persons and animals
approaching traffic or cross-traffic
BAS Plus may not detect narrow vehicles
driving in front of you, such as motorcycles
and vehicles driving offset from your vehicle
center.
71 Safety and Security
Driving safety systems
EBP
The Electronic Brake Proportioning (EBP)
enhances braking effectiveness by allow-
ing the rear brakes to supply a greater pro-
portion of the braking effort in straight line
braking without a loss of vehicle stability.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 the engine output, the ESP
®
works to stabilize the vehicle. The ESP® is
especially useful while driving off and on
wet or slippery road surfaces. The ESP
®
also stabilizes the vehicle during braking
and steering maneuvers.
The ESP
® warning lamp v in the instru-
ment cluster flashes when the ESP® is en-
gaged.
The ESP
® warning lamp v in the instru-
ment cluster comes on when you switch on
the ignition (
page 344). It goes out when
the engine is running.
Warning!G
When the EBP is malfunctioning, the ABS,
BAS, BAS Plus* and ESP® are also switched
off.
If the EBP is malfunctioning, the brake sys-
tem will still function with full brake boost.
However, the rear wheels could lock up dur-
ing emergency braking situations, for exam-
ple. You could lose control of the vehicle and
cause an accident. Adapt your driving style
to the changed driving characteristics.
Warning!G
Never switch off the ESP® when you see the
ESP® warning lamp v flashing in the in-
strument cluster. In this case 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.