MERCEDES-BENZ C-CLASS SALOON 2014 Repair Manual

always rest on the seat cushion of the front-
passenger seat. The backrest of the forwards- facing child restraint system must, as far as
possible, be resting on the backrest of the
rear reclining seat. Always comply with the
child restraint system manufacturer's instal-
lation instructions.
After the system self-test, the PASSENGER
AIR BAG OFF or PASSENGER AIR BAG ON
indicator lamp display the status of the front- passenger front airbag (Y page 54).
Further information can be found under
"Problems with the automatic front-
passenger front airbag deactivation system"
(Y page 59). 58
Occupant safetySafety

Problems with automatic front-passenger front airbag deactivation
Be sure to observe the notes on "System self-test" (Y
page 57).Problem
Possible causes/consequences and
M
MSolutions The PASSENGER AIR
BAG OFF indicator
lamp lights up and
remains lit, even
though the front-
passenger seat is occu-
pied by an adult or a
person with a build cor-responding to that of an
adult. The classification of the person on the front-passenger seat is
incorrect.
X Make sure the conditions for a correct classification of the per-
son on the front-passenger seat are met (Y page 54).
X If the PASSENGER AIR BAG OFF indicator lamp remains lit, the
front-passenger seat may not be used.
X Have the automatic front-passenger front airbag deactivation
system checked as soon as possible at a Mercedes-Benz Ser-
vice Centre. The PASSENGER AIR
BAG OFF indicator
lamp does not light up
and/or does not stay
on.
The front-passenger
seat is:
R empty
R occupied with a rear-
ward-facing child
restraint system The automatic front-passenger front airbag deactivation system is
malfunctioning.
X Make sure there is nothing between the seat and the child
restraint system.
X Make sure that the entire base of the child restraint system rests
on the seat cushion.
X Make sure that the seat cushion length is fully retracted.
X When installing the child restraint system, make sure that the
seat belt is tight. Do not pull the seat belt tight with the front-
passenger seat adjustment. This could result in the seat belt and the child restraint system being pulled too tightly.
X Check that the child restraint system is installed correctly.
X Make sure that no objects are applying additional weight to the
seat.
X If the PASSENGER AIR BAG OFF indicator lamp remains off and/
or the PASSENGER AIR BAG ON indicator lamp lights up, do not
install a rearward-facing child restraint system on the front-
passenger seat. It is recommended that you fit the restraint
system to a suitable rear seat.
X Have the automatic front-passenger front airbag deactivation
system checked as soon as possible at a Mercedes-Benz Ser-
vice Centre. Occupant safety
59Safety Z

Deployment of belt tensioners and air-
bags
Important safety notes G
WARNING
After the airbag deploys, the airbag parts are
hot. There is a risk of injury.
Do not touch the airbag parts. Have a
deployed airbag replaced at a qualified spe-
cialist workshop as soon as possible. G
WARNING
Pyrotechnic seat belt tensioners that have
been deployed are no longer operational and
are unable to perform their intended protec-
tive function. This poses an increased risk of
injury or even fatal injury.
Therefore, have pyrotechnic belt tensioners
which have been triggered immediately
replaced at a qualified specialist workshop.
Mercedes-Benz recommends that you have
the vehicle towed to a qualified specialist
workshop after an accident. Take this into
account, particularly if a seat belt tensioner
was triggered or an airbag was deployed.
An electric motor is used by PRE-SAFE ®
to
trigger the tightening of the seat belt in haz-
ardous situations. This procedure is reversi-
ble.
If the belt tensioners are triggered or an air-
bag is deployed, you will hear a bang, and a
small amount of powder may also be
released. The 6restraint system warning
lamp lights up.
Only in rare cases will the bang affect your
hearing. In general, the powder released is
not hazardous to health but may cause short- term breathing difficulties to persons suffer-
ing from asthma or other pulmonary condi-
tions. Provided it is safe to do so, you should
leave the vehicle immediately or open the
window in order to prevent breathing difficul- ties. Operation During the first stage of a collision, the
restraint system control unit evaluates impor- tant physical data relating to vehicle deceler-
ation or acceleration, such as:
R duration
R direction
R intensity
Based on the evaluation of this data, the
restraint system control unit triggers the seat
belt tensioners in the event of a head-on or
rear collision.
A seat belt tensioner can only be triggered if:
R the ignition is switched on
R the components of the restraint system are
operational; see "Restraint system warning
lamp" (Y page 45)
R the belt tongue has engaged in the belt
buckle of the respective front seat
The seat belt tensioners in the rear compart-
ment are triggered independently of the lock
status of the seat belts.
If the restraint system control unit detects a
high severity of an accident, in certain head-
on collisions, additional components of the
restraint system are deployed independently
of each another:
R front airbags and driver's kneebag
R windowbag, if the system determines that
deployment can offer additional protection
to that provided by the seat belt
On vehicles with the automatic front-
passenger front airbag deactivation system:
depending on the person in the front-
passenger seat, the front-passenger front air-
bag is either disabled or enabled. The front-
passenger front airbag can only be deployed
in an accident if the PASSENGER AIR BAG ON indicator lamp is lit. Observe the information
on the PASSENGER AIR BAG indicator lamps
(Y page 46).
Your vehicle has two-stage front airbags. In
the first deployment stage, the front airbag is
filled with propellant gas to reduce the risk of 60
Occupant safetySafety

injuries. The front airbag is fully deployed if
the second deployment stage is activated
within a few milliseconds.
The activation threshold for the seat belt ten-
sioners and airbags is determined based on
the evaluation of the vehicle's rate of decel-
eration or acceleration at various points in the vehicle. This process is pre-emptive in nature.The triggering/deployment process should
take place in good time at the start of the
collision.
The rate of vehicle deceleration or accelera-
tion and the direction of the force are essen-
tially determined by:
R the distribution of forces during the colli-
sion
R the collision angle
R the deformation characteristics of the vehi-
cle
R the characteristics of the object with which
the vehicle has collided
Factors which can only be seen and measured
after a collision has occurred do not play a
decisive role in the deployment of an airbag,
nor do they provide an indication of airbag
deployment.
The vehicle may be deformed significantly
without an airbag being deployed. This is the
case if only parts which are relatively easily
deformed are affected and the rate of decel-
eration is not high. Conversely, an airbag may be deployed even though the vehicle suffers
only minor deformation. This is the case if, for
example, very rigid vehicle parts such as lon-
gitudinal body members are hit, and sufficient deceleration occurs as a result. If the restraint system control unit detects a
side impact or if the vehicle overturns, the
applicable components of the restraint sys-
tem are activated independently of each
other depending on the apparent type of acci-
dent. If the system determines that, in this
situation, triggering can offer additional pro-
tection, the seat belt tensioners are also trig-
gered.
R Sidebags on the side on which an impact
occurs, independent from the seat belt ten-
sioner and seat belt usage
Vehicles with the automatic front-
passenger front airbag deactivation sys-
tem: the sidebag on the front-passenger
side (front) deploys under the following
conditions:
- an occupant is detected on the front-
passenger seat or
- the belt tongue is engaged in the belt
buckle of the front-passenger seat
R Windowbag on the side on which an impact
occurs, independent of seat belt usage and
regardless of whether the front-passenger
seat is occupied
R Windowbags on the driver's and front-
passenger side in certain situations if the
vehicle overturns and if the system deter-
mines that deployment can offer additional
protection to that provided by the seat belt
i Not all airbags are deployed in an acci-
dent. The different airbag systems work
independently of each other.
How the airbag system works is deter-
mined by the severity of the accident detec-
ted, especially the vehicle deceleration or
acceleration, and the apparent type of acci- dent:
R frontal collision
R side impact
R overturn Occupant safety
61Safety Z

PRE-SAFE
®
(anticipatory occupant
protection)
Introduction PRE-SAFE
®
takes pre-emptive measures to
protect occupants in certain hazardous sit-
uations.
Important safety notes !
Make sure that there are no objects in the
footwell under or behind the seats when
moving the seats back. There is a risk that
the seats and/or the objects could be dam-
aged.
Although your vehicle is equipped with a PRE-
SAFE ®
system, the possibility of injury in the
event of an accident cannot be ruled out.
Always adapt your driving style to suit the
prevailing road and weather conditions and
maintain a safe distance from the vehicle in
front. Drive carefully.
Function PRE-SAFE
®
intervenes:
R in emergency braking situations, e.g. when
BAS is activated
R in critical driving situations, e.g. when phys-
ical limits are exceeded and the vehicle
understeers or oversteers severely
R vehicles with the Driving Assistance pack-
age: when a driver assistance system inter-
venes powerfully or the radar sensor sys-
tem detects an imminent danger of colli-
sion in certain situations
PRE-SAFE ®
takes the following measures
depending on the hazardous situation detec-
ted:
R the front seat belts are pre-tensioned.
R if the vehicle skids, the sliding sunroof and
the side windows are closed so that only a
small gap remains. The panorama sliding
sunroof is completely closed.
R vehicles with the memory function for the
front-passenger seat: the front-passenger seat is adjusted if it is in an unfavourable
position.
If the hazardous situation passes without
resulting in an accident, PRE-SAFE ®
slackens
the belt pre-tensioning. All settings made by
PRE-SAFE ®
can then be reversed.
If the seat belt pre-tensioning is not reduced:
X Move the seat backrest or seat back
slightly when the vehicle is stationary.
Seat belt pre-tensioning is reduced and the
locking mechanism is released.
The seat-belt adjustment is an integral part of
the PRE-SAFE ®
convenience function. You
will find information on the convenience func-
tion under "Belt adjustment" (Y page 50). PRE-SAFE
®
PLUS (anticipatory occu-
pant protection PLUS)
Introduction PRE-SAFE
®
PLUS is only available in vehicles
with the Driving Assistance package.
Using the radar sensor system, PRE-SAFE ®
PLUS is able to detect that a head-on or rear-
end collision is imminent. In certain hazard-
ous situations, PRE-SAFE ®
PLUS takes pre-
emptive measures to protect the vehicle
occupants.
Important safety notes The intervention of PRE-SAFE
®
PLUS cannot
prevent an imminent collision.
The driver is not warned when PRE-SAFE ®
PLUS intervenes.
PRE-SAFE ®
PLUS does not intervene:
R if the vehicle is reversing
R when the vehicle is towing a trailer and
there is a risk of a rear-end collision
PRE-SAFE ®
PLUS does not perform braking
actions while the vehicle is in motion or when
Parking Guidance is active. 62
Occupant safetySafety

Function
PRE-SAFE
®
PLUS intervenes in certain situa-
tions if the radar sensor system detects an
imminent head-on or rear-end collision.
PRE-SAFE ®
PLUS takes the following meas-
ures depending on the hazardous situation
detected:
R If the radar sensor system detects that a
head-on collision is imminent, the seat
belts are pre-tensioned.
R If the radar sensor system detects that a
rear-end collision is imminent:
- the rear hazard warning lamps are acti-
vated and flash at a higher frequency.
- the brake pressure is increased if the
driver applies the brakes when the vehi-
cle is stationary.
- the seat belts are pre-tensioned.
The PRE-SAFE ®
PLUS braking application is
cancelled:
R if the accelerator pedal is depressed when
a gear is engaged
R if the risk of a collision passes or is no lon-
ger detected
R if DISTRONIC PLUS indicates an intention
to pull away
If the hazardous situation passes without
resulting in an accident, the original settings
are restored. Automatic measures after an acci-
dent
Immediately after an accident, the following
measures are implemented, depending on
the type and severity of the impact:
R the hazard warning lamps are activated
R the emergency lighting is activated
R the vehicle doors are unlocked
R the front side windows are lowered
R vehicles with a memory function: the elec-
trically adjustable steering wheel is raised
R the engine is switched off R
vehicles with the Mercedes-Benz emer-
gency call system: automatic emergency
call
R vehicles with the hybrid drive system: the
hybrid system is deactivated Children in the vehicle
Important safety notes
Accident statistics show that children
secured in the rear seats are safer than chil-
dren secured in the front-passenger seat. For this reason, Mercedes-Benz strongly advises
that you install a child restraint system on a
rear seat. Children are generally better pro-
tected there.
If a child younger than 12 years old and under 1.50 m in height is travelling in the vehicle:
R always secure the child in a child restraint
system suitable for Mercedes-Benz vehi-
cles. The child restraint system must be
appropriate to the age, weight and size of
the child
R be sure to observe the instructions and
safety notes in this section in addition to
the child restraint system manufacturer's
installation instructions
R always pay attention to the instructions
and safety notes on the automatic front-
passenger front airbag deactivation system
(Y page 54) G
WARNING
If you leave children unattended in the vehi-
cle, they may be able to set the vehicle in
motion if, for example, they:
R release the parking brake
R shift the automatic transmission out of park
position Por shift manual transmission into
neutral
R start the engine
In addition, they may operate vehicle equip-
ment and become trapped. There is a risk of
an accident and injury. Children in the vehicle
63Safety
Z

When leaving the vehicle, always take the key
with you and lock the vehicle. Never leave
children unattended in the vehicle. G
WARNING
If persons (particularly children) are exposed
to heat or cold for a prolonged period, there is a risk of serious or even fatal injuries. Never
leave persons (particularly children) unatten-
ded in the vehicle. G
WARNING
If the child restraint system is placed in direct sunlight, the parts could become very hot.
Children could be suffer burns by touching
these parts, in particular on the metallic parts
of the child restraint system. There is a risk of injury.
If you and your child leave the vehicle, always
make sure that the child restraint system is
not in direct sunlight. Cover it with a blanket, for example. If the child restraint system has
been exposed to direct sunlight, leave it to
cool down before securing the child in it.
Never leave children unattended in the vehi-
cle.
Always ensure that all vehicle occupants have their seat belts fastened correctly and are sit-
ting properly. Particular attention must be
paid to children.
Observe the safety notes on the seat belt
(Y page 47) and the information on the cor-
rect use of the seat belt (Y page 48).Child restraint system
Observe the instructions for correct use of
the child restraint system (Y page 68).
For safety reasons, Mercedes-Benz recom-
mends that you only use a child restraint sys-
tem recommended by Mercedes-Benz
(Y page 71). G
WARNING
If the child restraint system is incorrectly fit-
ted on the seat position suitable for this pur-
pose, it cannot perform its intended protec-
tive function. In the event of an accident,
sharp braking or a sudden change in direction, the child may not be held securely. There is an
increased risk of serious or even fatal injuries.
Observe the manufacturer's installation
instructions and the correct use for the child
restraint system. Make sure that the entire
surface of the child restraint system is resting
on the seat surface. Never place objects
under or behind the child restraint system,
e.g. cushions. Only use child restraint sys-
tems with the original cover designed for
them. Only replace damaged covers with gen- uine covers. G
WARNING
If the child restraint system is fitted incor-
rectly or is not secured, it can come loose in
the event of an accident, heavy braking or a
sudden change in direction. The child
restraint system could be thrown about, strik- ing vehicle occupants. There is an increased
risk of injury, possibly even fatal.
Always fit child restraint systems properly,
even if they are not being used. Make sure
that you observe the child restraint system
manufacturer's installation instructions.
You will find further information on stowing
objects, luggage and loads securely under
"Loading guidelines" (Y page 368). G
WARNING
Child restraint systems or their securing sys-
tems that have been damaged or subjected to a load in an accident cannot perform their
intended protective function. In the event of
an accident, sharp braking or a sudden
change in direction, the child may not be held securely. There is an increased risk of serious
or even fatal injuries.
Immediately replace child restraint systems
that have been damaged or subjected to a 64
Children in the vehicleSafety

load in an accident. Have the child restraint
securing systems checked in a qualified spe-
cialist workshop before fitting a child restraint
system again.
Securing systems for the child restraint sys-
tem are: R the seat belt system
R the ISOFIX securing rings
R the Top Tether anchorages
If it is absolutely necessary to carry a child on
the front-passenger seat, be sure to observe
the information on "Child restraint systems
on the front-passenger seat" (Y page 66).
Observe the warning labels in the vehicle inte-
rior and on the child restraint system.
i It is advisable to use Mercedes-Benz care
products to clean child restraint systems
recommended by Mercedes-Benz. You can obtain information about this at any
Mercedes-Benz Service Centre. ISOFIX child seat securing system
G
WARNING
ISOFIX child restraint systems do not offer
sufficient protective effect for children whose weight is greater than 22 kg who are securedusing the safety belt integrated in the child
restraint system. The child could, for example, not be restrained correctly in the event of an
accident. This poses an increased risk of
injury or even fatal injury.
If the child weighs more than 22 kg, only use
ISOFIX child restraint systems with which the child is also secured with the vehicle seat belt. Also secure the child restraint system with the
Top Tether belt, if available.
When fitting a child restraint system, be sure to observe the manufacturer's installation
instructions and the instructions for correct
use of the child restraint system
(Y page 68). Before every trip, make sure that the ISOFIX
child restraint system is engaged correctly in
both ISOFIX securing rings.
! When fitting the child restraint system,
make sure that the seat belt for the centre
seat does not get trapped. Otherwise, the
seat belt could be damaged. :
ISOFIX securing rings
Vehicles with rear seat armrest: adjust the
rear seat armrest so that ISOFIX securing
rings :for the ISOFIX child restraint system
are accessible.
X Install the ISOFIX child restraint system on
both ISOFIX securing rings :.
ISOFIX is a standardised securing system for specially designed child restraint systems on
the rear seats. ISOFIX securing rings :for
two ISOFIX child restraint systems are fitted
on the left and right of the rear seats.
Secure child restraint systems without an
ISOFIX child seat securing system using the
seat belts in the vehicle. When fitting a child
restraint system, be sure to observe the man-
ufacturer's installation and operating instruc-
tions and the instructions for correct use of
the child restraint system (Y page 68). Top Tether
Introduction Top Tether provides an additional connection
between the child restraint system secured
with ISOFIX and the vehicle. It helps reduce
the risk of injury even further. If the child Children in the vehicle
65Safety Z

restraint system is fitted with a Top Tether
belt, this should always be used.
Important safety notes G
WARNING
If the rear seat backrests are not locked, they
could fold forwards in the event of an acci-
dent, heavy braking or sudden changes of
direction. As a result, child restraint systems
cannot perform their intended protective
function. Rear seat backrests that are not
locked can also cause additional injuries, e.g. in the event of an accident. This poses an
increased risk of injury or even fatal injury.
Always lock rear seat backrests after fitting a Top Tether belt. Observe the lock verificationindicator. Adjust the rear seat backrests so
that they are in an upright position.
If the rear seat backrest is not engaged and
locked, this will be shown in the multifunction display in the instrument cluster. A warning
tone also sounds.
Top Tether anchorages Top Tether anchorage points
=are fitted in
the rear compartment behind the outer head
restraints on the parcel shelf. X
Move head restraint :upwards.
X Fold up cover ;of Top Tether anchorage
=.
X Fit the ISOFIX child restraint system with
Top Tether. Always comply with the child
restraint system manufacturer's installa-
tion instructions when doing so.
X Route Top Tether belt Aunder head
restraint :between the two head restraint
bars.
X Hook Top Tether hook ?of Top Tether belt
A into Top Tether anchorage =.
Make sure that Top Tether belt Ais not
twisted.
X Tension Top Tether belt A. Always comply
with the child restraint system manufactur- er's installation instructions when doing so.
X Fold down cover ;of Top Tether anchor-
age =.
X If necessary, move head restraint :back
down again slightly (Y page 121).
Make sure that you do not interfere with the
correct routing of Top Tether belt A. Child restraint system on the front-
passenger seat
General notes Accident statistics show that children
secured in the rear seats are safer than chil-
dren secured in the front-passenger seat. For
this reason, Mercedes-Benz strongly advises
that you install a child restraint system on a
rear seat. 66
Children in the vehicleSafety

Vehicles with the automatic front-passenger
front airbag deactivation system: if it is abso- lutely necessary to fit a child restraint systemto the front-passenger seat, always observe
the information on "Automatic front-
passenger front airbag deactivation system"
(Y page 54).
You can thus avoid the risks that could arise
as a result of:
R a child restraint system that is not detected
by the automatic front-passenger front air- bag deactivation system
R the unintentional disabling of the front-
passenger front airbag
R the unsuitable positioning of the child
restraint system, e.g. too close to the dash-
board Please observe the warning notice on the
front-passenger sun visor, see the illustra-
tion. G
WARNING
If you secure a child on the co-driver's seat in a rearward-facing child restraint system and
the PASSENGER AIR BAG ON indicator lamp
lights up, the co-driver's airbag could be
deployed in the event of an accident. The childcould be struck by the airbag. There is an
increased risk of injury, possibly even fatal.
In this case, always ensure that the co-driver's
airbag is disabled. The PASSENGER AIRBAG
OFF indicator lamp must light up.
NEVER use a rearward facing child restraint
on a seat protected by an ACTIVE AIRBAG in front of it, DEATH or SERIOUS INJURY to the
CHILD can occur.
If the PASSENGER AIR BAG ON indicator lamp
is lit, the front-passenger front airbag is ena-
bled (Y page 46).
Vehicles without the automatic front-
passenger front airbag deactivation
system If the front-passenger seat of your vehicle is
not equipped with the automatic front-
passenger front airbag deactivation system,
this is indicated by a special sticker. The
sticker is affixed to the side of the dashboard
on the front-passenger side. The sticker is
visible when you open the front-passenger
door.
In this case, always fit the rearward-facing
child restraint system to a suitable rear seat
(Y page 68).
Observe the following information under
"Rearward-facing child restraint system" and
"Forward-facing child restraint system" as
well as information on the suitable position-
ing of the child restraint system
(Y page 68).
Rearward-facing child restraint system If it is absolutely necessary to fit a rearward-
facing child restraint system to the front-
passenger seat, always make sure that the
front-passenger front airbag is disabled. Only
if the PASSENGER AIR BAG OFF indicator
lamp is permanently lit (Y page 46) is the
front-passenger front airbag disabled. Children in the vehicle
67Safety Z