MERCEDES-BENZ S CLASS 2023 Workshop Manual

A malfunction has occurred in the restraint sys-tem if:
= the restraint system warning lamp u does
not light up when the vehicle is switched on
= the restraint system warning lamp u lights
up continuously or repeatedly during a journey
If components of the restraint system have been
deployed, the restraint system warning lamp u
lights up continuously.&WARNING Risk of injury due to malfunc-
tions in the restraint system
Components in the restraint system may be activated unintentionally or not deploy as plan-
ned in an accident.
Have the restraint system checked and
repaired immediately at a quali"Ned spe-
cialist workshop.
Plug-in hybrid vehicles: if the restraint system is
malfunctioning, the automatic high voltage emer-
gency shuto"M may not function.
&DANGER Risk of fatal injuries due to mal-
functions of the automatic high-voltage
emergency shuto"M
In the event of an accident, the high-voltage
on-board electrical system may not be deacti-
vated as intended.
You may be electrocuted if you touch the dam-
aged component parts of the high-voltage on-
board electrical system.
Have the automatic high-voltage emer-
gency shuto"M checked and repaired
immediately at a quali"Ned specialist
workshop.A"ser an accident, switch o"M the vehicle
immediately.
Mercedes-Benz recommends that you have the
vehicle towed to a quali"Ned specialist workshop.
Function of the seat belt warning lamp
The seat belt warning lamp

motion, the rear seat belt status display appearsagain.
Display on the driver\bs display
Every time the vehicle is switched on, the rear
seat belt status display informs you for a certain
amount of time which rear seat belt is not fas-
tened.
You can determine the status of the rear seat belt
by the color of the seat symbol on the driver\bs dis- play as follows:
= Gray: the rear seat belt is not fastened.
=Green: the seat belt tongue of a rear seat belt
is engaged in the seat belt buckle of the dis- played seat.
= Red: the person in the rear seat has unfas-
tened their seatbelt.
Function of the PASSENGER AIR BAG indicator
lamps (front passenger air bag)
The PASSENGER AIR BAG indicator lamps display
the status of the front passenger air bag.
If the front passenger seat is occupied or a child restraint system is installed on the front
passenger seat, you must make sure both before
and also during the journey that the status of the front passenger air bag is correct for the situation.&WARNING Risk of potentially fatal injuries
due to objects trapped under the front
passenger seat
Objects trapped under the front passenger
seat may interfere with the function of the
automatic front passenger air bag shuto"M or
damage the system.
Do not stow any objects under the front
passenger seat.When the front passenger seat is occu-
pied, ensure that no objects have
become trapped beneath the front
passenger seat.50Occupant safety

Self-test: when the vehicle is switched on, both
the PASSENGER AIR BAG ON and OFF indicator
lamps light up simultaneously for several seconds.
A"ser the self-test, you can determine the status of
the front passenger air bag as follows:
= Front passenger air bag disabled: PASSENGER
AIR BAG OFF lights up continuously.
The front passenger air bag will not be
deployed in the event of an accident. If
PASSENGER AIR BAG OFF is lit, no one may
use the front passenger seat.
If a rearward-facing child restraint system is installed on the front passenger seat,
PASSENGER AIR BAG OFF must be lit continu-
ously.
= Front passenger air bag enabled: PASSENGER
AIR BAG ON lights up for up to 60 seconds or
until both the PASSENGER AIR BAG ON and
OFF indicator lamps go out.
The front passenger air bag may be deployed
during an accident. If the front passenger air
bag is in this status, no rearward-facing child restraint system may be installed on the front
passenger seat.\bIf you are driving with a child in the vehicle, observe the information in the chapter "Chil-
dren in the vehicle" (  page 67)&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 classi"Ncation 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.
Both before and during the journey,
ensure that the status of the front
passenger airbag is correct.
Malfunction of the automatic front passenger air
bag shuto"M
The PASSENGER AIR BAG OFF indicator lamp and
the u restraint system indicator lamp light up
simultaneously.
In this case, no one may use the front passenger seat and no child restraint system may be instal-
led on the front passenger seat.
Have the automatic front passenger air bag shut-
o"M checked and repaired immediately at a quali-
"Ned specialist workshop.
Be sure to also observe the following further rela-
ted subjects:
= Child restraint system on the front passenger
seat (  page 71)
Occupant safety51

Deactivating or activating the front passenger air
bag
The automatic front passenger air bag shuto"M can
deactivate or activate the front passenger air bag
according to the situation.
This happens automatically as a result of the clas- si"Ncation of the person or child restraint system
on the front passenger seat.
You cannot manually deactivate or activate the front passenger air bag.
Also observe the following information:
= The status of the front passenger air bag, see
"Function of the PASSENGER AIR BAG indica-
tor lamps" (  page 50)
= Notes on using the front passenger seat, see
"Information on the automatic front passenger air bag shuto"M" ( page 53)
= If you are driving with a child in the vehicle,
observe the chapter "Children in the vehicle"
(  page 67)
Function of the REAR SEAT AIR BAG indicator
lamps_Le"s rear seat^Right rear seat
You can disable or enable the rear air bags individ-
ually via the multimedia system (  page 53).
Self-test: when the vehicle is switched on, both
the REAR SEAT AIR BAG ON and OFF indicator
lamps light up simultaneously for several seconds.
A"ser the self-test, you can determine the status of
the rear air bag as follows:
= Rear air bag disabled: REAR SEAT AIR BAG
OFF lights up continuously.
The rear air bag will not be deployed in the event of an accident.
= Rear air bag enabled: REAR SEAT AIR BAG ON
lights up for up to 60 seconds or until both the
REAR SEAT AIR BAG ON and OFF indicator
lamps go out.
The rear air bag may be deployed during an
accident.
Information on the rear air bag in the seat back-
rest of the front seat
Before beginning the journey, observe the infor- mation on the rear air bag (  page 65). Make
sure the status of each rear air bag is correct for
the situation.52Occupant safety

Enabling/disabling the rear airbag via the multi-
media system
Multimedia system:
4 © 5
Settings 5
Vehicle
5 Occupant Protection
Enable or disable the desired rear airbag
under Rear Airbags .
Information on the child restraint system
When installing a child restraint system, observe
the notes in "Children in the vehicle"
(  page 67).
Notes on the child restraint system 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 in
the DEATH of or SERIOUS INJURY to the CHILD.
Also pay particular attention to the notes on rear-
ward-facing or forward-facing child restraint sys- tems on the front passenger seat (  page 71).
Notes for vehicles with rear air bag
If you install a child restraint system on the le"s or
right rear seat, pay particular attention to the
notes for vehicles with rear air bag: (  page 73).
Notes for vehicles with belt air bag
If you install a child restraint system on the le"s or
right rear seat, pay particular attention to the
information on the belt air bag in the rear seat belt: (  page 63).
Information on the automatic functions of the
restraint system
Function of the automatic front passenger air bag
shuto"M
A person on the front passenger seat must
observe the following information:
= Sit correctly (  page 46).
= Fasten the seat belt correctly (  page 47).
The automatic front passenger air bag shuto"M can
activate or deactivate the front passenger air bag
according to the situation.
Make sure you observe the following information: = Status of the front passenger air bag: see
"Function of the PASSENGER AIR BAG indica-
tor lamps" (  page 50).
= When installing a child restraint system on the
front passenger seat, observe the vehicle-spe-ci"Nc information (  page 71).
Occupant safety53

Status of the front passenger air bag in relation to
the stature of the person:
= Front passenger air bag disabled: PASSENGER
AIR BAG OFF lights up continuously.
The front passenger air bag will not be
deployed in the event of an accident. If
PASSENGER AIR BAG OFF is lit, no one may use the front passenger seat.
= Front passenger air bag enabled: PASSENGER
AIR BAG ON lights up for up to 60 seconds or
until both the PASSENGER AIR BAG ON and
OFF indicator lamps go out.
The front passenger air bag may be deployed
during an accident. Observe the following information on the correct seat position
(  page 46).
Vehicles with rear seats: a person of smaller
stature should use a rear seat.System limits
The front passenger air bag may otherwise be dis- abled by mistake, for example, in the following sit-
uation:
= 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 li"sed o"M the seat surface.*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 accident situation detected, the window air bag on the front passenger side maydeploy. The air bag will be deployed regardless of
whether the front passenger seat is occupied.
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.
54Occupant safety

=Vehicles with memory function in the rear
passenger compartment: moving the outer
rear seats to a more favorable seat position.
= Vehicles with multicontour seat: increasing the
lateral support by in"Oating the seat side bol-
sters of the seat backrest.
= 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 Assist
Function of PRE-SAFE n
Impulse Side
If an imminent side impact is detected, PRE-
SAFE n
Impulse Side can pre-emptively move the
front seat vehicle occupant\bs upper body towards
the center of the vehicle. It does this by rapidly
in"Oating an air cushion in the outer seat side bol-
ster of the seat backrest on the side on which the impact is anticipated. This increases the distance
between the door and the vehicle occupant.
Vehicles with E-ACTIVE BODY CONTROL: the body
can also be slightly raised.
Occupant safety55

If PRE-SAFEn
Impulse Side has been deployed or
is faulty, the PRE-SAFE Pulse Side Inoperative
See Operator's Manual display message appears
(  page 490).
Seat belt adjustment function
Vehicles with PRE-SAFE n
: a"ser you have fastened
the seat belt of the front seat, it may adjust itself
against your body by pulling at the shoulder until somewhat tight. Do not hold the seat belt tightlywhile it is adjusting.
This function is a reminder that all vehicle occu-
pants must wear their seat belts correctly.
You can activate and deactivate the seat belt
adjustment function using the multimedia system (  page 56).
Activating/deactivating seat belt adjustment via
the multimedia system
Multimedia system:
4 © 5
Settings 5
Vehicle
5 Occupant Protection
Activate or deactivate Belt adjustment.
Function of the rear seat belt feeder
The seat belt feeder for the rear seat helps you
fasten your seat belt.
When the door is closed, the seat belt feeder
extends.
\bIf the vehicle is equipped with the MBUX Inte-
rior Assistant, the seat belt feeder can extend
when you reach for the seat belt tongue.
The seat belt feeder retracts again in the following
cases:
= the seat belt tongue is engaged in the seat
belt buckle
= the seat belt tongue is not engaged in the seat
belt buckle within a certain time
= the respective door is opened
=a certain speed is exceeded a"ser pulling away&WARNING Risk of injury or death due to
an extended seat belt extender while the vehicle is in motion
If the seat belt does not sit correctly on the
body, it cannot perform its intended protective
function.
Always ensure that the seat belt
extender is retracted while the vehicle is
in motion.
If the seat belt feeder does not automatically
retract, you must push it back by hand against the
resistance all the way to the stop before starting
the vehicle.
You can deactivate the seat belt feeder. Activate the child safety lock for the rear side windows(  page 81).
When installing a child restraint system on the
rear seat, observe the vehicle-speci"Nc information
(  page 67).
56Occupant safety

Overview of the automatic measures a"ser an acci-
dent
Depending on the type and severity of the acci-
dent, and depending on the vehicle\bs equipment, the following measures may be implemented, for
example:
= automatic braking (post-collision brake)
= activating the hazard warning lamps
= triggering an automatic emergency call
(  page 392)
= switching o"M the engine
To start the vehicle again, switch the vehicle
o"M and on once more (  page 203). Depend-
ing on the type and severity of the accident,
you may no longer be able to start the vehicle.
= switching o"M the fuel supply
= Plug-in hybrid: switching o"M the hybrid system
and high-voltage on-board electrical system
= unlocking the vehicle doors
= lowering the side windows
= displaying the emergency guide on the central
display
= switching on the interior lighting
Function of the post-collision brake a"ser an acci-
dent
Depending on the accident situation, the post-col-
lision brake can minimise the severity of a further
collision or even avoid it.
If an accident is detected, the post-collision brake can initiate automatic braking. When the vehiclehas 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
Purpose and function of the restraint system
Overview of deployment situations (restraint sys- tem)
Make sure that the following prerequisites in par-
ticular have been met so that the components of the restraint system are able to provide the inten-ded level of protection:
= Sit correctly (  page 46).
= Fasten the seat belt correctly (  page 47).
- Function of the seat belt warning lamp
(  page 49).
- Function of the rear seat belt status dis-
play (  page 49).
= The u restraint system warning lamp is not
lit up a"ser the self-test (  page 48).
= The PASSENGER AIR BAG indicator lamps dis-
play the correct status of the front passenger air bag (  page 50).
= The REAR SEAT AIR BAG indicator lamps dis-
play the correct status of the rear air bags (  page 52).
Occupant safety57

Depending on the detected deployment situation,the components of the restraint system can be
activated or deployed independently of each other:
= Emergency Tensioning Device: frontal impact,
rear impact, side impact, rollover
= Driver\bs air bag, front passenger air bag: fron-
tal impact
= Knee bag: frontal impact
= Side impact air bag: side impact
= Window curtain air bag: side impact, rollover,
frontal impact
= Rear air bag in the seat backrest of the front
seat: frontal impact
= Belt air bag in the rear seat belt: frontal
impact
= Cushion air bag in the reclining rear seat: fron-
tal impact
= PRE-SAFE n
Impulse Side: side impact
The installation location of an air bag is identi"Ned
by the AIRBAG symbol (  page 64).Observe the information on the function of the
restraint system (  page 58).
Information on how the restraint system works
How the restraint system functions depends on
the severity of the impact detected and the appa- rent type of accident.
For more information about types of accidents,
see "Overview of deployment situations"
(  page 57).
The activation thresholds for the components of
the restraint system are determined based on the
evaluation of the sensor values measured at vari-
ous points in the vehicle. This process is pre-emp-
tive in nature. The triggering/deployment of the
components of the restraint system must take place in good time at the start of the collision.
Factors that can be seen and measured only a"ser
a collision has occurred cannot play a decisive
role in air bag deployment. Nor do they provide an indication of air bag deployment.
The vehicle may be deformed signi"Ncantly without
an air bag being deployed. This is the case if only
parts that are relatively easily deformed are a"Mec-
ted and the rate of vehicle deceleration is not
high. Conversely, an air bag may be deployed
even though the vehicle su"Mers only minor defor-
mation. If very rigid vehicle parts such as longitu-
dinal members are hit, this may result in su"P-
ciently high levels of vehicle deceleration.
Depending on the apparent type of accident and
the detected deployment situation, Emergency
Tensioning Devices and/or air bags supplement the protection o"Mered by a correctly worn seat
belt.
When enabled, an air bag can provide additional
protection for the respective vehicle occupant.
Potential protection provided by each air bag: = Knee bag: thigh, knee and lower leg
= Driver\bs air bag, front passenger air bag: head
and ribcage
= Window curtain air bag: head
= Side impact air bag: ribcage, also pelvis for
front seat occupants
= Rear air bag: head58Occupant safety