MERCEDES-BENZ C CLASS 2023 Service Manual

Seat belt adjustment function
Vehicles with PRE-SAFEn
: aser a front seat belt
has been fastened, the automatic seat belt adjust-
ment may apply a certain amount of tightening
force. Do not hold the seat belt tightly while it is
adjusting.
You can activate and deactivate the seat belt
adjustment function using the multimedia system (  page 39).
Activating/deactivating seat belt adjustment via
the multimedia system
Multimedia system:
4 © 5
Settings 5
Vehicle
5 Occupant Protection
Activate or deactivate Belt adjustment.
Releasing seat belts
Press the release button in the seat belt
buckle and guide the seat belt back with the
seat belt tongue.Seat belt warning function for the driver and front passenger
The

When enabled, an air bag can provide additional
protection for the respective vehicle occupant.
Potential protection provided by each air bag:
= Knee air bag: thigh, knee and lower leg
= Driver\bs air bag, front passenger air bag: head
and ribcage
= Window air bag: head
= Side air bag: ribcage, also pelvis for front seat
occupants
Information on child restraint systems on the front passenger seat&WARNING Risk of injury or fatal injuries if
the front passenger air bag is enabled
If the front passenger air bag is enabled, a
child on the front passenger seat may be struck by the front passenger air bag in theevent of an accident.
NEVER use a rearward-facing childrestraint system on a seat with an ENA-
BLED FRONT AIR BAG. This can result inthe DEATH of or SERIOUS INJURY to the
CHILD.
When installing a child restraint system on the front passenger seat, observe the vehicle-speciNc
information (  page 59). Also, always observe
the notes on rearward-facing or forward-facing
child restraint systems on the front passenger seat (  page 58).
Information on the automatic front passenger air
bag shutoM
Only when the PASSENGER AIR BAG OFF indica-
tor lamp is oM can the front passenger air bag
deploy in the event of an accident. If the front passenger seat is occupied, make sure, both
before and during the journey, that the status of
the front passenger air bag is correct
(  page 44).
*NOTE Deployment of components of the
restraint system when the front passenger
seat is unoccupied
In an accident, the components of the restraint system may deploy unnecessarily on
the front passenger side if:
= There are heavy objects on the front
passenger seat.
= The seat belt tongue is engaged in the seat
belt buckle of the front passenger seat and
the front passenger seat is unoccupied.
Store objects in a suitable place.Only one person should use each seat
belt at any one time.
Depending on the detected accident situation, the window air bag on the front passenger side maydeploy. The air bag is deployed regardless of
whether the front passenger seat is occupied.
40Occupant safety

Protection provided by the airbags
Depending on the accident situation, an airbag
may supplement the protection oMered by a cor-
rectly fastened seat belt.
&WARNING Risk of injury or death due to
an incorrect seat position
If you deviate from the correct seat position,
the airbag cannot perform its intended protec- tive function.
Each vehicle occupant must make sure of the
following:
= Fasten seat belts correctly. Pregnant
women must take particular care to ensure
that the lap belt never lies across the
abdomen.
= Adopt the correct seat position and keep
as far away as possible from the airbags.
= Observe the following information.
Always make sure that there are no
objects between the airbag and vehicle
occupant.To avoid the risks resulting from the deployment
of an airbag, each vehicle occupant must observe
the following information in particular:
= Before starting your journey, adjust your seat
correctly; the driver\bs seat and front
passenger seat should be moved as far back as possible.
When doing so, always observe the informa-
tion on the correct driver\bs seat position
(  page 89).
= Only hold the steering wheel by the steering
wheel rim. This allows the airbag to be fully
deployed.
= Always lean against the seat backrest when
the vehicle is in motion. Do not lean forwards
or against the door or side window. You may otherwise be in the deployment area of the
airbags.
= The occupants must always keep their feet on
the Ooor. Do not put your feet on the cockpit,
for example. Your feet may otherwise be in the
deployment area of the airbag.
= If children are traveling in the vehicle, observe
the additional notes (  page 49).=
Always stow and secure objects correctly.
Objects in the vehicle interior may prevent an air-
bag from functioning correctly. Each vehicle occu-
pant must always make sure of the following in
particular:
= There are no people, animals or objects
between the vehicle occupants and an airbag.
= There are no objects between the seat, door
and door pillar (B-pillar).
= There are no hard objects, e.g. coat hangers,
hanging on the grab handles or coat hooks.
= There are no accessories, such as mobile navi-
gation devices, mobile phones or cup holders, within the deployment area of an airbag, e.g.on the cockpit, on the door, on the side win-
dow or on the side trim.
In addition, no connecting cables, tensioning straps or retaining straps must be routed or
attached to the vehicle within the deployment
area of an airbag. Always comply with the
accessory manufacturer\bs installation instruc-
tions and, in particular, the notes on suitable
places for installation.Occupant safety41

=There are no heavy, sharp-edged or fragile
objects in the pockets of your clothing. Store
such objects in a suitable place.
Limitations of the protection provided by airbags
&WARNING Risk of injury due to modiNca-
tions to the cover of an airbag
If you change the cover of an airbag or attach
objects, e.g. even stickers, to it, the airbag may no longer function as intended.
Never modify the cover of an airbag.Do not attach any objects to the cover.
The installation location of an airbag is identiNed
by the AIRBAG symbol (  page 39).
Objects in the deployment area of an airbag may prevent the airbag from functioning correctly.
&WARNING Risk of injury from objects in
the deployment area of an airbag
Objects in the deployment area of an airbag
can hinder or prevent the correct deployment
of the airbag.
The airbag may then deploy in an uncontrolled manner and may even cause additional inju-
ries to the vehicle occupants by deploying.
This may be the case in particular if the airbag is integrated into the seat.
Always stow and secure objects cor-
rectly.Before commencing your journey, make
sure that no objects are stowed in the
deployment area of an airbag.&WARNING Risk of injury or death due to
the use of unsuitable seat covers
Due to unsuitable seat covers, the airbags
cannot protect vehicle occupants as intended.
In addition, the operation of the automatic
front passenger airbag shutoM could be
restricted.
You should only use seat covers that
have been approved for the correspond-
ing seats by Mercedes-Benz.&WARNING Risk of injury due to malfunc-
tioning sensors in the door
The function of the airbags can be impaired
due to modiNcations or incorrect work per-
formed on the doors or door trim, or if the
doors are damaged.
Never modify the doors or parts of the
doors.Always have work on the doors or door
trim carried out at a qualiNed specialist
workshop.&WARNING Risk of injury due to deployed
airbag
A deployed airbag no longer oMers any protec-
tion.
42Occupant safety

Have the vehicle towed to a qualiNed
specialist workshop in order to have the
deployed airbag replaced.Have deployed airbags replaced immediately.
Status of the front passenger front airbag

q Function of the automatic front passenger air
bag shutoM
The automatic front passenger air bag shutoM is
able to detect whether the front passenger seat is
occupied by a person or a child restraint system. The front passenger air bag is enabled or disabled
accordingly.
&WARNING Risk of injury or death due to
objects under the co-driver seat
Objects trapped under the co-driver seat can
interfere with the function of the automatic
co-driver airbag shutoM or damage the system.
Do not store any objects under the co-
driver seat.When the co-driver seat is occupied,make sure that no objects are trapped
under the co-driver seat.
When Ntting a child restraint system to the front
passenger seat, observe the vehicle-speciNc infor-
mation (  page 59). Also, always observe the
notes on rearward-facing or forward-facing child
restraint systems on the front passenger seat
(  page 58).
A person on the front passenger seat must observe the following information:
= Fasten seat belts correctly (  page 35).
= Sit in an almost upright seat position with their
back against the seat backrest.
= Sit with their feet resting on the Ooor, if possi-
ble.
The front passenger air bag may otherwise be dis-
abled by mistake, for example, in the following sit- uations:
= The front passenger transfers their weight by
supporting themselves on a vehicle armrest.
= The front passenger sits in such a way that
their weight is raised from the seat surface.&WARNING Risk of injury or death due to a
disabled front passenger airbag
The front passenger airbag is disabled when
the PASSENGER AIR BAG OFF indicator lamp
is lit.
A person in the front passenger seat could
then, for example, come into contact with the
vehicle interior, especially if the person is sit- ting too close to the cockpit.
If the front passenger seat is occupied, always ensure that:
= The classiNcation of the person in the front
passenger seat is correct and the front
passenger airbag is enabled or disabled in
accordance with the person in the front
passenger seat.
= The front passenger seat has been moved
as far back as possible.
= The person is seated correctly.
Occupant safety43

Both before and during the journey,
ensure that the status of the front
passenger airbag is correct.
If the front passenger seat is occupied, the classi-
Ncation of the person or child restraint system on
the front passenger seat takes place aser the
front passenger air bag shutoM self-test. The
PASSENGER AIR BAG indicator lamps display the status of the front passenger air bag.
Always observe the notes on the function of the PASSENGER AIR BAG indicator lamps
(  page 44).

qFunction of the PASSENGER AIR BAG indicator
lamps
Self-test of automatic front passenger air bag shutoM
When the vehicle is switched on, a self-test is per-
formed during which the two PASSENGER AIR
BAG ON and OFF indicator lamps light up simulta-
neously.
The status of the front passenger air bag is dis-
played via the PASSENGER AIR BAG indicator lamps aser the self-test:
= ON is lit: the front passenger air bag may
deploy during an accident.
The indicator lamp goes out aser 60 seconds.
= ON and OFF are not lit: the front passenger air
bag may deploy during an accident.
= OFF is lit: the front passenger air bag is disa-
bled. It will then not be deployed in the event of an accident.
If the PASSENGER AIR BAG ON indicator lamp is
oM, only the PASSENGER AIR BAG OFF indicator
lamp shows the status of the front passenger air
bag. The PASSENGER AIR BAG OFF indicator lamp
may be lit continuously or be oM.
If the PASSENGER AIR BAG OFF indicator lamp
and the u restraint system warning lamp light
up simultaneously, the front passenger seat may not be used. Also in this case, do not Nt a child
restraint system to the front passenger seat. Have
the automatic front passenger air bag shutoM44Occupant safety

checked and repaired immediately at a qualiNed
specialist workshop.
Status display
If the front passenger seat is occupied, ensure,
both before and during the journey, that the sta- tus of the front passenger air bag is correct for
the current situation.
Aser Ntting a rearward-facing child restraint sys-
tem to the front passenger seat: PASSENGER AIR
BAG OFF must be lit continuously.&WARNING Risk of injury or fatal injury
when using a rearward-facing child
restraint system while the co-driver airbag
is enabled
If you secure a child in a rearward-facing child
restraint system on the co-driver seat and the
PASSENGER AIR BAG OFF indicator lamp is
oM, the co-driver airbag can deploy in the
event of an accident.
The child could be struck by the airbag.
Always ensure that the co-driver airbag is
disabled. The PASSENGER AIR BAG OFF
indicator lamp must be lit.NEVER use a rearward-facing child restraint system on a seat with an ENA-
BLED FRONT AIRBAG; DEATH or SERI-
OUS INJURY to the CHILD can occur.
When Ntting a child restraint system to the front
passenger seat, observe the vehicle-speciNc infor-
mation (  page 58).
Depending on the child restraint system and the stature of the child, the PASSENGER AIR BAG OFF
indicator lamp may be oM. In this case, do not Nt
the rearward-facing child restraint system to the front passenger seat.
Instead, Nt the rearward-facing child restraint sys-
tem to a suitable rear passenger compartment
seat.
Aser Ntting a forward-facing child restraint sys-
tem to the front passenger seat: depending on the
child restraint system and the stature of the child, PASSENGER AIR BAG OFF may be lit continuously
or be oM. Always observe the following informa-
tion.&WARNING Risk of injury or death due to
incorrect positioning of the forward-facing
child restraint system
If you secure a child in a forward-facing child
restraint system on the front passenger seat
that is positioned too close to the cockpit, in
the event of an accident, the child could:
= come into contact with the vehicle interior
if the PASSENGER AIR BAG OFF indicator
lamp is lit, for example
= be struck by the airbag if the PASSENGER
AIR BAG OFF indicator lamp is oM.
Always move the front passenger seat as
far back as possible and fully retract the
seat cushion length adjustment. While
doing so, always make sure that the
shoulder belt strap is correctly routed
from the seat belt outlet of the vehicle to
the shoulder belt guide on the child
restraint system. The shoulder belt strap
must be routed forwards and downwardsOccupant safety45

from the seat belt outlet. If necessary,adjust the seat belt outlet and the front
passenger seat accordingly.Always comply with the child restraint
system manufacturer\bs installation
instructions.
When Ntting a child restraint system to the front
passenger seat, observe the vehicle-speciNc infor-
mation (  page 58).
If a person is sitting on the front passenger seat:
PASSENGER AIR BAG OFF may be lit continuously
or be oM, depending on the person\bs stature.
A person on the front passenger seat must always observe the following information:
= If the front passenger seat is occupied by an
adult or a person with a stature corresponding
to that of an adult, the PASSENGER AIR BAG
OFF indicator lamp must be oM. This indicates
that the front passenger air bag is enabled.
If the PASSENGER AIR BAG OFF indicator
lamp is lit continuously, an adult or person
with a build corresponding to that of an adult must not use the front passenger seat.
Instead, they should use a rear passenger
compartment seat.
= If the front passenger seat is occupied by a
person of smaller stature (e.g. a teenager or
small adult), the PASSENGER AIR BAG OFF indicator lamp is either lit continuously or
remains oM, depending on the classiNcation.
- If the PASSENGER AIR BAG OFF indicator
lamp is oM: move the front passenger seat
as far back as possible, or the person of
smaller stature should use a rear
passenger compartment seat.
- If the PASSENGER AIR BAG OFF indicator
lamp is lit continuously: the person of
smaller stature should not use the front
passenger seat.&WARNING Risk of injury or death when
the PASSENGER AIR BAG OFF indicator
lamp is lit
If the PASSENGER AIR BAG OFF indicator lamp remains lit aser the self-test, the front
passenger airbag is disabled.
If the front passenger seat is occupied, always
ensure that:
= The classiNcation of the person in the front
passenger seat is correct and the front
passenger airbag is enabled or disabled in
accordance with the person in the front passenger seat.
= The person is seated properly with a cor-
rectly fastened seat belt.
= The front passenger seat has been moved
as far back as possible.
Be sure to also observe the following further rela-
ted subjects:
= Child restraint system on the front passenger
seat (  page 58)
46Occupant safety

PRE-SAFEn
system
Function of PRE-SAFE n
(anticipatory occupant
protection)
PRE-SAFE n
is able to detect certain critical driv-
ing situations and implement pre-emptive meas-
ures to protect the vehicle occupants.
PRE-SAFE n
can implement the following meas-
ures independently of each other:
= Tightening the seat belts on the driver\bs seat
and front passenger seat.
= Closing the side windows.
= Vehicles with sliding sunroof: closing the slid-
ing sunroof.
= Vehicles with memory function: moving the
front passenger seat to a more favorable seat
position.
= PRE-SAFE n
Sound: provided that the multime-
dia system is switched on, generating a brief
noise signal to stimulate the innate protective mechanism of a person\bs hearing.
*NOTE Damage caused by objects in the
footwell or behind the seat
The automatic adjustment of the seat position
may result in damage to the seat and/or the object.
Stow objects in a suitable place.
Backing up the PRE-SAFE n
system measures
If an accident did not occur, the pre-emptive
measures that were taken are reversed.
You will need to perform certain settings yourself.
If the seat belt pre-tensioning is not reduced,
move the seat backrest back slightly.
The locking mechanism releases.
Function of PRE-SAFE n
PLUS (anticipatory occu-
pant protection plus)
PRE-SAFE n
PLUS can detect certain impacts, par-
ticularly an imminent rear impact, and take pre-
emptive measures to protect the vehicle occu-
pants. These measures cannot necessarily pre-
vent an imminent impact.
PRE-SAFE n
PLUS can implement the following
measures independently of each other:
= Tightening the seat belts on the driver\bs seat
and front passenger seat.
= Increasing brake pressure when the vehicle is
stationary. This brake application is canceled
automatically when the vehicle pulls away.
If an accident did not occur, the pre-emptive
measures that were taken are reversed.
System limits
The system will not initiate any action in the fol- lowing situations:
= when backing up
The system will not initiate any braking application
in the following situations:
= whilst driving
or
= when entering or exiting a parking space while
using Active Parking AssistOccupant safety47

Function of PRE-SAFEn
Impulse Side
If an imminent side impact is detected, PRE-
SAFE n
Impulse Side can pre-emptively move the
upper body of the vehicle occupant in the front seat towards the center of the vehicle. It does thisby rapidly inOating an air cushion in the outer seat
side bolster of the seat backrest on the side on which the impact is anticipated. This increases
the distance between the door and the vehicle
occupant.
If PRE-SAFE n
Impulse Side has been deployed or
is faulty, the PRE-SAFE Pulse Side Inoperative
See Operator's Manual display message appears
(  page 383).
Automatic measures aser an accident
Depending on the type and severity of the acci- dent, and depending on the vehicle\bs equipment,the following measures can be implemented, forexample:
= Automatic braking (post-collision brake)
= Activating the hazard warning light system
=Triggering an automatic emergency call
(  page 291)
= Switching oM the engine
To start the vehicle again, switch the vehicle
oM and on once more (  page 150). Depend-
ing on the type and severity of the accident,
you may no longer be able to start the vehicle.
= Switching oM the fuel supply system
= Unlocking the vehicle doors
= Lowering the side windows
= Displaying the emergency guide in the central
display
= Switching on the interior lighting
Function of the post-collision brake
Depending on the accident situation, the post-col-
lision brake can minimize the severity of a further
collision or even avoid it.
If an accident is detected, the post-collision brake can implement automatic braking. When the vehi- cle has come to a standstill, the electric parking
brake is automatically applied.The driver can cancel automatic braking by taking
the following actions:
= Braking more strongly than automatic braking
= Fully depressing the accelerator pedal with
force
Safely transporting children in the vehicle
Always observe when children are traveling in the vehicle
\bAlso strictly observe the safety notes for the
speciNc situation. In this way, you can recog-
nize potential risks and avoid dangers if chil- dren are traveling in the vehicle
(  page 49).
Be diligent
Bear in mind that negligence when securing a
child in the child restraint system may have seri-
ous consequences. Always be diligent in securing
a child carefully before every journey.
Never allow babies and children to travel sitting
on the lap of another vehicle occupant.
48Occupant safety