MERCEDES-BENZ S-Class 2011 W221 Repair Manual

fastened, the 7 seat belt warning lamp
lights up for six seconds each time the engine
is started. It then goes out once the driver and
the front passenger have fastened their seat
belts.
If the driver's seat belt is not fastened after
the engine is started, an additional warning
tone will sound. The warning tone goes out
after approximately six seconds or once the
driver's seat belt is fastened.
If, after six seconds, the driver or front-
passenger have not fastened their seat belts
and the doors are closed:
R the 7 seat belt warning lamp remains
illuminated as long as either the driver's or
front-passenger seat belt is not fastened.
R if the vehicle speed exceeds 15 mph
(25 km/h), the 7 seat belt warning
lamp lights up. Additionally, a warning tone
will sound with increasing intensity for a
maximum of 60 seconds or until the
driver's and front-passenger seat belt are
fastened.
If the driver/front passenger unfasten their
seat belt while the vehicle is in motion, the
7 seat belt warning lamp lights up and a
warning tone sounds again.
The warning tone ceases even if the driver or
front passenger have still not fastened their
seat belt after 60 seconds. The 7 seat belt
warning lamp stops flashing but remains
illuminated.
After the vehicle comes to a standstill, the
warning tone is reactivated and the 7 seat
belt warning lamp flashes again if the vehicle
speed again exceeds 15 mph (25 km/h) .
The 7 seat belt warning lamp only goes
out if:
R both the driver and the front passenger
have fastened their seat belts.
or
R the vehicle is stationary and a door is open.
i For more information on the 7 seat
belt warning lamp, see "Indicator andwarning lamps in the instrument cluster,
seat belt" ( Y page 414).
Emergency Tensioning Devices and
seat belt force limiters
The front seat belts and the outer seat belts
in the rear are equipped with ETDs and belt
force limiters.
! If the front-passenger seat is not
occupied, do not engage the seat belt
tongue in the buckle on the front-
passenger seat. Otherwise, the Emergency
Tensioning Device could be triggered in the
event of an accident.
The belt tensioners tighten the seat belts in
an accident, pulling them close against the
body.
Belt tensioners do not correct incorrect seat
positions or incorrectly fastened seat belts.
Belt tensioners do not pull vehicle occupants
back towards the backrest.
Seat belt force limiters, when triggered, help
to reduce the peak force exerted by the seat
belt on the vehicle occupant.
The front belt force limiters are synchronized
with the front air bags, which take on a part
of the deceleration force. Thus, the force
exerted on the occupant is distributed over a
greater area.
The belt tensioners can only be activated
when:
R the ignition is switched on.
R the restraint systems are operational; see
"SRS warning lamp" ( Y page 42).
R the belt tongue is engaged in the buckle on
each of the three-point seat belts in the
front.
R the front-passenger seat is occupied and
the belt tongue is engaged in the buckle on
the front-passenger side.
The belt tensioners on the outside seats in the
rear compartment are triggered
independently of the lock status of the seat
belts.
Occupant safety59SafetyZ

The belt tensioners are triggered depending
on the type and severity of an accident:
R in the event of a head-on or rear-end
collision, if the vehicle decelerates or
accelerates rapidly in a longitudinal
direction during the initial stages of the
impact
R in the event of a side impact, on the side
opposite the impact if the vehicle
decelerates or accelerates rapidly in a
lateral direction
R in certain situations, if the vehicle
overturns and the system determines that
it can provide additional protection
If the air bags are deployed, you will hear a
bang and a small amount of powder may also
be released. Only in rare cases will the bang
affect your hearing. The powder that is
released generally does not constitute a
health hazard. The 6 SRS warning lamp
lights up.GWarning
Pyrotechnic Emergency Tensioning Devices
that have been deployed must be renewed.
For your safety, when disposing of Emergency
Tensioning Devices, always observe the
safety instructions. These are available from
any authorized Mercedes-Benz Center.
The PRE-SAFE ®
system has electrically
operated reversible pre-tensioners that do
not require replacement after activation.
Automatic comfort-fit feature
The front seat belts have an automatic
comfort-install feature. In vehicles with a rear
bench seat with electrically adjustable outer
seats, the seat belts for the outer seats have
an automatic comfort-install feature. The
automatic comfort-install feature reduces the
retraction force of the seat belts. This results
in increased seat belt comfort.
Children in the vehicle
Important safety notes
GWarning
When leaving the vehicle, always remove the
SmartKey from the ignition lock. Always take
the SmartKey with you and lock the vehicle.
Do not leave children unattended in the
vehicle, even if they are secured in a child
restraint system, or with access to an
unlocked vehicle. A child's unsupervised
access to a vehicle could result in an accident
and/or serious personal injury. The children
could:
R injure themselves on parts of the vehicle
R be seriously or fatally injured through
excessive exposure to extreme heat or cold
R injure themselves or cause an accident with
vehicle equipment that can be operated
even if the SmartKey is removed from the
ignition lock or removed from the vehicle,
such as seat adjustment, steering wheel
adjustment, or the memory function
If children open a door, they could injure other
persons or get out of the vehicle and injure
themselves or be injured by following traffic.
Do not expose the child restraint system to
direct sunlight. The child restraint system's
metal parts, for example, could become very
hot, and the child could be burned on these
parts.
GWarning!
Do not carry heavy or hard objects in the
passenger compartment or trunk unless they
are firmly secured in place.
Unsecured or improperly positioned cargo
increases a child's risk of injury in the event
of
R strong braking maneuvers
R sudden changes of direction
R an accident
60Children in the vehicleSafety

If an infant or child is traveling in the vehicle:XSecure the child using an infant or child
restraint system appropriate to the age and
weight of the child.XMake sure that the infant or child is
properly secured at all times while the
vehicle is in motion.
Child restraint systems
Important safety notes
GWarning
Observe "Important safety notes"
( Y page 60).
We recommend all infants and children be
properly restrained using the child restraint
systems at all times while the vehicle is in
motion.
The use of infant or child restraints is required
by law in all 50 states, the District of
Columbia, the U.S. territories and all
Canadian provinces.
Infants and small children should always be
seated in an infant or child seat restraint
system appropriate for the size and weight of
the child. They must be properly secured in
accordance with the manufacturer's
installation instructions for the infant or child
seat restraint system. All infant and child seat
restraint systems must comply with the US
Federal Motor Vehicle Safety Standards 213
and 225 and Canadian Motor Vehicle Safety
Standards 213 and 210.2.
A statement by the child restraint
manufacturer of compliance with these
standards can be found on the instruction
label on the restraint system. You will also
find the statement in the instruction manual
provided with the child restraint system.
When using an infant restraint system, child
restraint system or booster seat, make sure
to carefully read and follow all manufacturer's
instructions for installation and use.
Please read the warning labels affixed to the
interior of the vehicle or to the infant restraint
or child restraint system.GWarning
According to accident statistics, children are
safer when properly restrained on the rear
seats than on the front-passenger seat. Thus,
we strongly recommend that children be
placed in the rear seats whenever possible.
Regardless of seating position, children 12
years old and under must be seated and
properly secured in an appropriately sized
child restraint system or booster seat
recommended for the size and weight of the
child.
The infant or child restraint system 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 always
sit as upright as possible, wear the seat belt
properly and use an appropriate sized infant
restraint, toddler restraint, or booster seat
recommended for the size and weight of the
child.
Children can be killed or seriously injured by
an inflating air bag. Note the following
important information when circumstances
require you to place a child in the front-
passenger seat:
R Your vehicle is equipped with air bag
technology designed to deactivate the
front-passenger front air bag in your vehicle
when the system 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.
R A child in a rear-facing child restraint on the
front-passenger seat will be seriously
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 eliminate
Children in the vehicle61SafetyZ

this risk completely is never to place a child
in a rear-facing child restraint in the front-
passenger seat. We therefore strongly
recommend that you always place a child
in a rear-facing child restraint on the rear
seat.
R If you install a rear-facing child restraint on
the front-passenger seat, make sure the
42 indicator lamp is
illuminated, indicating that the front-
passenger front air bag is deactivated.
Should the 42 indicator lamp
not illuminate or go out while the restraint
is installed, please check installation.
Periodically check the 42
indicator lamp while driving to make sure
the 42 indicator lamp is
illuminated. If the 42 indicator
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 seriously
injured or even killed if the front-passenger
front air bag inflates.
R If you place a child in a forward-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
- secure child restraint with the vehicle's
seat belt according to the child seat
manufacturer's instructions
R For children larger than a typical 12-month-
old child, the front-passenger front air bag
can be activated or deactivated.GWarning
Infants and small children should never share
a seat belt with another occupant. During an
accident, they could be crushed between the
occupant and seat belt.
A child's risk of serious or fatal injuries is
significantly increased if the child restraints
are not properly secured in the vehicle and/
or the child is not properly secured in the child
restraint.
Children too big for a toddler restraint must
ride in seats using regular seat belts. Position
the shoulder belt across the chest and
shoulder, not face or neck. A booster seat
may be necessary to achieve proper seat belt
positioning for children over 41 lb (18 kg) until
they reach a height where a lap/shoulder belt
fits properly without a booster.
When the child restraint is not in use, remove
it from the vehicle or secure it with the seat
belt to prevent the child restraint from
becoming a projectile in the event of an
accident.
Special seat belt retractorGWarning
Observe "Important safety notes"
( Y page 60).
All seat belts in the vehicle, except the
driver's seat belt, are equipped with a special
seat belt retractor. When activated, the
special seat belt retractor ensures that the
seat belt cannot slacken after being fastened.
Installing a child restraint system:
XAlways comply with the manufacturer's
installation instructions.XPull the seat belt smoothly from the inertia
reel.XEngage the seat belt tongue in the belt
buckle.
Activating the special seat belt retractor:
XPull the seat belt out fully and let the inertia
reel retract it again.
While the seat belt is retracting, you should
hear a ratcheting sound. The special seat
belt retractor function is enabled.XPush down on the child restraint system to
take up any slack.62Children in the vehicleSafety

Removing a child restraint system/
deactivating the special seat belt retractor:XAlways comply with the manufacturer's
installation instructions.XPress the seat belt release button and
guide the belt tongue to the belt outlet.
The special seat belt retractor function is
deactivated.GWarning
Never release the seat belt buckle while the
vehicle is in motion, since the special seat belt
retractor will be deactivated.
LATCH-type child restraint (ISOFIX) in
the rear
GWarning
Observe "Important safety notes"
( Y page 60).
GWarning
Children that are too large for a child restraint
must travel in seats using normal seat belts.
Position shoulder belt across the chest and
shoulder, not face or neck.
In order to attain the correct seating position
for children weighing over 41 lb (18 kg), it may
be necessary to use a booster seat until they
reach a height where a normal lap/shoulder
seat belt lies properly across their bodies
without the need for a booster seat.
Install the child restraint system according to
the manufacturer's instructions.
The child restraint system must be installed
firmly on both brackets.
An incorrectly installed child restraint system
can come loose in the event of an accident,
causing the child to be severely or fatally
injured.
Child restraint systems/child restraint
retaining brackets that are damaged or have
suffered damage due to an impact must be
replaced.
ISOFIX is a standardized securing system for
specially designed child restraint systems on
the rear seats. Securing rings for two LATCH-
type (ISOFIX) child restraint systems are
installed on the left and right of the rear seats.
Use the vehicle's seat belts to install child
restraint systems without the ISOFIX
securing system. Follow the manufacturer's
instructions for of child restraint systems.
! Vehicles with a center seat in the rear:
when installing the LATCH-type (ISOFIX)
child restraint system, make sure that the
seat belt for the center seat does not get
trapped. Otherwise, the seat belt could be
damaged.
Installation instruction : indicates the
installation point of securing ring 2.
XMove the rear seat backrest of the
electrically adjustable rear seat to the
upright position ( Y page 102).XFold upholstered lining = and the Velcro
fastener upwards.XTurn installation aid ? to a vertical
position, so that upholstered lining = does
not fold back down.XInstall the LATCH-type (ISOFIX) child
restraint system on both securing
rings ;. Comply with the manufacturer's
instructions when installing the LATCH-
type (ISOFIX) child restraint system.GWarning!
Vehicles with rear power seats:
Children in the vehicle63SafetyZ

Never change the rear seat position after
installing the child restraint. This could
R damage the child restraint
R introduce undesirable slack or tension into
the seat belt
R loosen the child restraint
R misposition the child restraint
All of the above will lessen the
effectiveness of the child restraint and thus
increase the chance or severity of injury in
an accident.
Top TetherGWarning
Observe "Important safety notes"
( Y page 60).
Top Tether provides an additional attachment
point between the "LATCH" type child seat
mount (ISOFIX) child restraint system and the
rear seat. This can further reduce the risk of
injury.
The Top Tether anchorages are located in the
rear compartment behind the head restraints.
XVehicles with electrically adjustable rear
seats: move the rear seat backrest to an
upright position ( Y page 102).XRemove corresponding protective cap :
from the Top Tether anchorage.XPlace protective cap : in a suitable place
(e.g. in the glove box).XSlide the head restraint upwards.XRoute Top Tether belt ? under the head
restraint between both head restraint bars.XEngage Top Tether hook = of Top Tether
belt ? into Top Tether anchorage ;.
Make sure that:
R Top Tether hook = is engaged in Top
Tether anchorage ;, as illustrated.
R Top Tether belt ? is not twisted.
R Top Tether belt ? can move freely
between the rear seat backrest and the
head restraint.XInstall the LATCH-type (ISOFIX) child
restraint system with Top Tether. Always
comply with the manufacturer's
installation instructions. Make sure that
Top Tether belt ? is taut.
The child restraint system with Top Tether
belt ? has been removed:
XSlide protective cap : onto Top Tether
anchorage ;.GWarning!
Vehicles with rear power seats:
Never change the rear seat position after
installing the child restraint. This could
R damage the child restraint
R introduce undesirable slack or tension into
the seat belt
R loosen the child restraint
R misposition the child restraint
64Children in the vehicleSafety

All of the above will lessen the
effectiveness of the child restraint and thus
increase the chance or severity of injury in
an accident.
Child-proof locks
Child-proof locks for the rear doors
GWarning
Observe "Important safety notes"
(Y page 60).
GWarning
Children could open a rear door from inside
the vehicle. This could result in serious
injuries or an accident. Therefore, when
children ride in the rear always secure the rear
doors with the child-proof locks.
You can secure each door individually with
the child-proof locks on the rear doors. A door
secured with a child-proof lock cannot be
opened from inside the vehicle. When the
vehicle is unlocked, the door can be opened
from the outside.
XTo activate: press the child-proof lock
lever up in the direction of arrow :.
XMake sure that the child-proof locks are
working properly.
XTo deactivate: press the child-proof lock
lever down in the direction of arrow ;.
Override feature for the rear side
windows
GWarning
Observe "Important safety notes"
(Y page 60).
GWarning
When children ride on the vehicle's rear seats,
activate the override switch. Otherwise, the
children could be injured, e.g. by trapping
themselves in the rear side window.
For the rear compartment, you can disable
operation of:
Rthe rear side windows
Rthe cigarette lighter in the rear
Radjustment of the front-passenger seat
from the rear compartment
Rthe sunblinds:
-in the roof
-of the rear window
-of the rear side windows
XTo activate/deactivate: press button :.
If indicator lamp ; is lit, the rear-
compartment functions are disabled. The
rear side windows can then only be
operated using the switches on the driver's
door. If indicator lamp ; is off, the
functions are enabled. The rear side
windows can be operated using the
switches in the rear compartment.
Children in the vehicle65SafetyZ

Panic alarmX To activate: press and hold !
button : for about one second.
An alarm sounds and the exterior lighting
flashes.XTo deactivate: press ! button :
again.
or
XInsert the SmartKey into the ignition lock.
or
XPress the KEYLESS-GO Start-Stop button.
The KEYLESS-GO key must be in the
vehicle.
i USA only:
This device complies with the part 15 of the
FCC regulations. Operation is subject to
the following two conditions:
1. This device may not cause interference,
and
2. This device must withstand any
interference received, including
interference that may cause undesired
operation.
Any unauthorized modification to this
device could void the user's authority to
operate the equipment.
i Canada only:
This device complies with the RSS-210
regulations of Industry Canada. Operation
is subject to the following two conditions:
1. This device may not cause interference,
and
2. This device must withstand any
interference received, including
interference that may cause undesired
operation of the device.
Any unauthorized modification to this
device could void the user's authority to
operate the equipment.
Driving safety systems
Driving safety systems overview
In this section, you will find information about
the following driving safety systems:
R ABS ( Anti-lock Braking System)
R BAS ( Brake Assist System)
R BAS PLUS ( Brake Assist System Plus*)
R Adaptive brake lamps
R ESP ®
(E lectronic Stability Program)
R EBD ( Electronic Brake force Distribution)
R ADAPTIVE BRAKE
R PRE-SAFE ®
Brake (vehicles with
DISTRONIC PLUS)
Important safety notes
GWarning
The following factors increase the risk of
accidents:
R Excessive speed, especially in turns
R Wet and slippery road surfaces
R Following another vehicle too closely
The driving safety systems described in this
section cannot reduce these risks or prevent
the natural laws of physics from acting on the
vehicle. They cannot increase braking or
steering efficiency beyond that afforded by
the condition of the vehicle brakes and tires
or the traction afforded.
Only a safe, attentive, and skillful driver can
prevent accidents.
The capabilities of a vehicle equipped with the
driving safety systems described in this
66Driving safety systemsSafety

section must never be exploited in a reckless
or dangerous manner which could jeopardize
the user's safety or the safety of others.
Always adjust your driving style to the
prevailing road and weather conditions and
keep a safe distance to other road users and
objects on the street.
If a driving system malfunctions, other driving
safety systems may also switch off. Observe
indicator and warning lamps that may come
on as well as messages in the multifunction
display that may appear.GWarning!
HYBRID vehicles: It is imperative that you read
the HYBRID Supplemental Operating
Instructions included in your vehicle literature
portfolio. You may otherwise not receive all
necessary safety information and warning for
the operation of your vehicle.
i In wintry driving conditions, always use
winter tires (M+S tires) and if necessary,
snow chains. Only in this way will the
driving safety systems described in this
section work as effectively as possible.
ABS (Anti-lock Braking System)
Important safety notes
GWarning
Observe "Important safety notes"
( Y page 66).
GWarning
Do not pump the brake pedal. Use firm, steady
brake pedal pressure instead. Pumping the
brake pedal defeats the purpose of the ABS
and significantly reduces braking
effectiveness.
ABS regulates brake pressure in such a way
that the wheels do not lock when you brake.
This allows you to continue steering the
vehicle when braking.
ABS works from a speed of about
5 mph (8 km/h) upwards, regardless of road-
surface conditions. ABS works on slippery
surfaces, even when you only brake gently.
The ! warning lamp in the instrument
cluster lights up when the ignition is switched
on. It goes out when the engine is running.
Braking
If ABS intervenes when braking, you will feel
a pulsing in the brake pedal.
XIf ABS intervenes: continue to depress the
brake pedal with force until the braking
situation is over.XTo make a full brake application:
depress the brake pedal with full force.GWarning
If the ABS malfunctions, other driving systems
such as the BAS or the ESP ®
are also switched
off. Observe indicator and warning lamps that
may come on as well as messages in the
multifunction display that may appear.
If the ABS malfunctions, the wheels may lock
during hard braking, reducing the steering
capability and extending the braking distance.
The pulsating brake pedal can be an
indication of hazardous road conditions and
functions as a reminder to take extra care
while driving.
BAS (Brake Assist System)
GWarning
Observe "Important safety notes"
( Y page 66).
BAS operates in emergency braking
situations. If you depress the brake pedal
quickly, BAS automatically boosts the braking
force, thus shortening the stopping distance.
XKeep the brake pedal firmly depressed until
the emergency braking situation is over.
ABS prevents the wheels from locking.Driving safety systems67SafetyZ

The brakes will function as usual once you
release the brake pedal. BAS is deactivated.GWarning
If the BAS malfunctions, the brake system still
functions, but without the additional brake
boost available that the BAS would normally
provide in an emergency braking maneuver.
Therefore, the braking distance may increase.
BAS PLUS (Brake Assist PLUS)
GWarning
Observe "Important safety notes"
( Y page 66).
At speeds above approximately
20 mph (30 km/h), BAS PLUS assists you
when braking in hazardous situations and
uses the radar sensor system to evaluate the
traffic conditions.
GWarning!
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.
Otherwise, you may not be able to recognize
dangerous situations until it is too late and
could cause an accident. Personal or fatal
injury to you or others may be the result.
i This equipment has been approved by the
FCC as a "Vehicular Radar System". The
radar sensor system is intended for use in
an automotive radar system only. Removal,
tampering, or altering of the device will void
any warranties, and is not permitted by the
FCC. Do not tamper with the device in any
way.
Any unauthorized modification to this
device could void the user's authority to
operate the equipment.
BAS PLUS can detect obstacles that are in the
path of your vehicle for an extended period of
time. Should you approach a detected
obstacle quickly, BAS PLUS calculates the
braking force necessary to avoid a rear-end
collision. Should you additionally apply the
brakes, BAS PLUS will automatically increase
the braking force to a level suitable for the
traffic conditions.
If BAS PLUS demands particularly high
braking force, PRE-SAFE ®
is activated
simultaneously.XKeep the brake pedal depressed until the
emergency braking situation is over.
ABS prevents the wheels from locking.
The brakes will work normally again when:
R you release the brake pedal
R no obstacle is detected in front of your
vehicle
R there is no longer any danger of a rear-end
collision
BAS PLUS is then deactivated.
At speeds up to approximately
40 mph (70 km/h), BAS PLUS can also detect
stationary obstacles, for example, stopped or
parked vehicles.
For BAS PLUS to assist you when driving, the
radar sensor system must be switched on and
operational. You can check this by activating
DISTRONIC PLUS ( Y page 325) or via the
"radar sensor" function in the on-board
computer( Y page 378).
GWarning!
BAS PLUS will only respond with brake
assistance if it has clearly detected an object.
Detection can be impeded by
R dirty or covered sensors
R snowfall or heavy rain
68Driving safety systemsSafety