2018 MERCEDES-BENZ C-CLASS SEDAN warning lights

If the PASSENGER AIR BAG ON indicator lamp is
off, only the PASSENGER AIR BAG OFF indicatorlamp shows the status of the front-passenger
front air bag. The PASSENGER AIR BAG OFF
indicator lamp may be lit continuously or be off.
If the status of the front-passenger front air bag
changes while the vehicle is in motion, an air bag
display message appears in the instrument clus-
ter (
Ypage 240). When the front-passenger
seat is occupied, always pay attention to the
PASSENGER AIR BAG OFF indicator lamp. Be
aware of the status of the front-passenger front
air bag both before and during the journey.
GWARNING
If the PASSENGER AIR BAG OFF indicator
lamp is lit, the front-passenger front air bag is
disabled. It will not be deployed in the event of
an accident and cannot perform its intended
protective function. A person in the front-
passenger seat could then, for example, come
into contact with the vehicle's interior, espe-
cially if the person is sitting too close to the
dashboard. This poses an increased risk of
injury or even fatal injury.
When the front-passenger seat is occupied,
always ensure that:
Rthe classification of the person in the front- passenger seat is correct and the front-
passenger front air bag is enabled or disa-
bled in accordance with the person in the
front-passenger seat
Rthe front-passenger seat has been moved
back as far back as possible.
Rthe person is seated correctly.
Make sure, both before and during the jour-
ney, that the status of the front-passenger
front air bag is correct.
GWARNING
If you secure a child in a rearward-facing child
restraint system on the front-passenger seat
and the PASSENGER AIR BAG OFF indicator
lamp is off, the front-passenger front air bag
may deploy in the event of an accident. The
child could be struck by the air bag. This poses an increased risk of injury or even fatal injury.
Make sure that the front-passenger front air
bag has been disabled. The PASSENGER AIR
BAG OFF indicator lamp must be lit.
If the PASSENGER AIR BAG OFF indicator lamp
stays off, do not install a rearward-facing child
restraint system on the front-passenger seat.
You can find more information on OCS under
"Problems with the Occupant Classification Sys-
tem" (
Ypage 55).
GWARNING
If you secure a child in a forward-facing child
restraint system on the front-passenger seat
and you position the front-passenger seat too close to the dashboard, in the event of an
accident, the child could:
Rcome into contact with the vehicle's inte-
rior if the PASSENGER AIR BAG OFF indi-
cator lamp is lit, for example
Rbe struck by the air bag if the PASSENGER
AIR BAG OFF indicator lamp is off
This poses an increased risk of injury or even fatal injury.
Always move the front-passenger seat as far
back as possible and fully retract the seat
cushion length. Always make sure that the
shoulder belt strap is correctly routed from
the vehicle belt sash guide to the shoulder
belt guide on the child restraint system. The
shoulder belt strap must be routed forwards
and downwards from the vehicle belt sash
guide. If necessary, adjust the vehicle belt
sash guide and the front-passenger seat
accordingly. Always observe the child
restraint system manufacturer's installation
instructions.
If OCS determines that:
Rthe front-passenger seat is unoccupied, the
PASSENGER AIR BAG OFF indicator lamp
lights up after the system self-test and
remains lit. This indicates that the front-
passenger front air bag is deactivated.
Rthe front-passenger seat is occupied by a
child of up to twelve months old, in a standard
child restraint system, the PASSENGER AIR
BAG OFF indicator lamp lights up after the
system self-test and remains lit. This indi-
Occupant safety53
Safety
Z

cates that the front-passenger front air bag is
deactivated.
But even in the case of a twelve-month-old
child, in a standard child restraint system, the
PASSENGER AIR BAG OFF indicator lamp can
go out after the system self-test. This indi-
cates that the front-passenger front air bag is
activated. The result of the classification is
dependent on, among other factors, the child
restraint system and the child's stature. It is
recommended that you install the child
restraint system on a suitable rear seat.
Rthe front-passenger seat is occupied by a per-
son with a smaller build (e.g. a teenager or
small adult), the PASSENGER AIR BAG OFF
indicator lamp lights up and remains lit after
the system self-test depending on the result
of the classification or, alternatively, goes out.
-if the PASSENGER AIR BAG OFF indicator
lamp is off, move the front-passenger seat
as far back as possible. Alternatively, a per-
son of smaller stature can sit on a rear seat.
-if the PASSENGER AIR BAG OFF indicator
lamp is lit, a person of smaller stature
should not use the front-passenger seat.
Rthe front-passenger seat is occupied by an
adult or a person of adult stature, the
PASSENGER AIR BAG OFF indicator lamp
goes out after the system self-test. This indi-
cates that the front-passenger front air bag is
activated.
If children are traveling in the vehicle, be sure to
observe the notes on "C hild
ren in the vehicle"
(Ypage 60).
When the Occupant Classification System
(OCS) is malfunctioning, the red 6restraint
system warning lamp on the instrument cluster
and the PASSENGER AIR BAG OFF indicator
lamp light up simultaneously. The front-
passenger front air bag is deactivated in this
case and does not deploy during an accident.
Have the Occupant Classification System (OCS)
checked and repaired immediately at a qualified
specialist workshop. Mercedes-Benz recom-
mends that you use an authorized Mercedes-
Benz Center for this purpose.
If the front-passenger seat, the seat cover or the
seat cushion are damaged, have the necessary
repair work carried out at a qualified specialist
workshop. Mercedes-Benz recommends that
you use an authorized Mercedes-Benz Center
for this purpose. For safety reasons, Mercedes-Benz recom-
mends that you only use seat accessories that
have been approved by Mercedes-Benz.
If the driver's air bag deploys, this does not
mean that the front-passenger front air bag will
also deploy. The Occupant Classification Sys-
tem (OCS) categorizes the occupant on the
front-passenger seat. Depending on that result,
the front-passenger front air bag is either ena-
bled or deactivated.
System self-test
GDANGER
If both the PASSENGER AIR BAG OFF and
PASSENGER AIR BAG ON indicator lamps do
not light up during the system self-test, the
system is malfunctioning. The front-
passenger front air bag might be triggered
unintentionally or might not be triggered at all
in the event of an accident with high deceler-
ation. This poses an increased risk of injury or
even fatal injury.
In this case the front-passenger seat may not
be used. Do not install a child restraint system
on the front-passenger seat. Have the Occu-
pant Classification System (OCS) checked
and repaired immediately at a qualified spe-
cialist workshop.
GWARNING
If the PASSENGER AIR BAG OFF indicator
lamp remains lit after the system self-test, the
front-passenger front air bag is disabled. It will
not be deployed in the event of an accident. In
this case, the front-passenger front air bag
cannot perform its intended protective func-
tion, e.g. when a person is seated in the front-
passenger seat.
That person could, for example, come into
contact with the vehicle's interior, especially
if the person is sitting too close to the dash-
board. This poses an increased risk of injury or
even fatal injury.
54Occupant safety
Safety

When the front-passenger seat is occupied,
always ensure that:
Rthe classification of the person in the front-passenger seat is correct and the front-
passenger front air bag is enabled or disa-
bled in accordance with the person in the
front-passenger seat
Rthe person is seated properly with a cor-
rectly fastened seatbelt
Rthe front-passenger seat has been moved
as far back as possible
If the PASSENGER AIR BAG OFF indicator
lamp remains lit when it should not, the front-
passenger seat may not be used. Do not
install a child restraint system on the front-
passenger seat. Have the Occupant Classifi-
cation System (OCS) checked and repaired
immediately at a qualified specialist work-
shop.
GWARNING
Objects between the seat surface and the
child restraint system could affect OCS oper- ation. This could result in the front-passenger
air bag not functioning as intended during an
accident. This poses an increased risk of
injury or even fatal injury.
Do not place any objects between the seat
surface and the child restraint system. The
entire base of the child restraint system must
always rest on the seat cushion of the front-
passenger seat. The backrest of the forward-
facing child restraint system must, as far as
possible, be resting on the backrest of the
front-passenger 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 displays the status of the front-passenger
front air bag (
Ypage 52). If the front-passenger
front air bag is enabled, the PASSENGER AIR
BAG ON indicator lamp lights up for 60 seconds
and then goes out.
If the PASSENGER AIR BAG ON indicator lamp is off, only the PASSENGER AIR BAG OFF indicator
lamp shows the status of the front-passenger
front air bag. The PASSENGER AIR BAG OFF
indicator lamp may be lit continuously or be off.
For more information about the OCS, see "Prob-
lems with the Occupant Classification System"
(
Ypage 55).
Problems with the Occupant Classification System (OCS)
Be sure to observe the notes on "System self-test" (Ypage 54).
Occupant safety55
Safety
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ProblemPossible causes/consequences andMSolutions
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 per-
son of a stature corre-
sponding to that of an
adult.The classification of the person on the front-passenger seat is incor-
rect.
XMake sure the conditions for a correct classification of the person
on the front-passenger seat are met (Ypage 52).
XIf the PASSENGER AIR BAG OFF indicator lamp remains lit, the front-
passenger seat may not be used.
XHave OCS checked as soon as possible at an authorized Mercedes- Benz Center.
The PASSENGER AIR
BAG OFF indicator lamp
does not light up and/or
does not stay on.
The front-passenger seat
is:
Runoccupied
Roccupied with the
weight of a child up to
twelve months old in a
child restraint system
OCS is malfunctioning.
XMake sure there is nothing between the seat cushion and the child
seat.
XMake sure that the entire base of the child restraint system rests on
the seat cushion of the front-passenger seat. The backrest of the
forward-facing child restraint system must lie as flat as possible
against the backrest of the front-passenger seat. If necessary,
adjust the position of the front-passenger seat.
XMake sure that the seat cushion length is fully retracted.
XWhen installing the child restraint system, make sure that the seat
belt is tight. Do not pull the seat belt tight using the front-passenger seat adjustment. This could result in the seat belt and the child
restraint system being pulled too tightly.
XCheck for correct installation of the child restraint system.
Make sure that the head restraint does not apply a load to the child
restraint system. If necessary, adjust the head restraint accord-
ingly.
XMake sure that no objects are applying additional weight onto the
seat.
XIf the PASSENGER AIR BAG OFF indicator lamp remains off and/or
the PASSENGER AIR BAG ON indicator lamp lights up, do not install a child restraint system on the front-passenger seat. It is recom-
mended that you install the child restraint system on a suitable rear
seat.
XHave OCS checked as soon as possible at an authorized Mercedes-Benz Center.
Deployment of Emergency Tensioning
Devices and air bags
Important safety notes
GWARNING
The air bag parts are hot after an air bag has
been deployed. There is a risk of injury.
Do not touch the air bag parts. Have a
deployed air bag replaced at a qualified spe-
cialist workshop as soon as possible.
GWARNING
A deployed air bag no longer offers any pro-
tection and cannot provide the intended pro-
tection in an accident. There is an increased
risk of injury.
Have the vehicle towed to a qualified special-
ist workshop in order to have a deployed air
bag replaced.
It is important for your safety and that of your
passenger to have deployed air bags replaced
56Occupant safety
Safety

and to have any malfunctioning air bags
repaired. This will help to make sure the air bags
continue to perform their protective function for
the vehicle occupants in the event of a crash.
GWARNING
Emergency Tensioning Devices that have
deployed pyrotechnically are no longer opera-
tional and are unable to perform their inten-
ded protective function. This poses an
increased risk of injury or even fatal injury.
Have pyrotechnically triggered Emergency
Tensioning Devices replaced immediately at a
qualified specialist workshop.
An electric motor is used by PRE-SAFE
®to trig-
ger the tightening of the seat belt in hazardous
situations. This procedure is reversible.
If Emergency Tensioning Devices are triggered
or air bags are deployed, you will hear a bang,
and some powder may also be released. The
6 restraint system warning lamp lights up.
Only in rare cases will the bang affect your hear-
ing. The powder that is released generally does
not constitute a health hazard, but it may cause short-term breathing difficulties in people with
asthma or other respiratory problems. Provided
it is safe to do so, you should leave the vehicle
immediately or open the window in order to pre-
vent breathing difficulties.
Air bags and pyrotechnic Emergency Tensioning
Devices (ETDs) contain perchlorate material,
which may require special handling and regard
for the environment. National guidelines must
be observed during disposal. In California, see
www.dtsc.ca.gov/HazardousWaste/
Perchlorate/index.cfm.
Method of operation
During the first stage of a collision, the restraint
system control unit evaluates important physi-
cal data relating to vehicle deceleration or accel-
eration, such as:
Rduration
Rdirection
Rintensity
Based on the evaluation of this data, the
restraint system control unit triggers the Emer-
gency Tensioning Devices during a frontal or
rear collision. An Emergency Tensioning Device can only be
triggered, if:
Rthe ignition is switched on
Rthe components of the restraint system are
operational. You can find further information
under "Restraint system warning lamp"
(
Ypage 45)
Rthe seat belt buckle tongue has engaged in
the belt buckle of the respective front seat
The Emergency Tensioning Devices in the rear
compartment are triggered independently of the
lock status of the seat belts.
If the restraint system control unit detects a
more severe accident, further components of
the restraint system are activated independ-
ently of each other in certain frontal collision
situations:
RFront air bags and driver's knee bag
RWindow curtain air bag, if the system deter-
mines that deployment can offer additional
protection to that provided by the seat belt
The front-passenger front air bag is activated or
deactivated depending on the person on t
he
front-passenger seat. The front-passenger front
air bag can only deploy in an accident if the
PASSENGER AIR BAG OFF indicator lamp is off.
Observe the information on the PASSENGER AIR
BAG indicator lamps (
Ypage 45).
Your vehicle has two-stage front air bags. In the
first deployment stage, the front air bag is filled
with propellant gas. The front air bag is fully
deployed with the maximum amount of propel-
lant gas if a second deployment threshold is
reached within a few milliseconds.
The activation threshold of the Emergency Ten-
sioning Devices and the air bags is determined
by evaluating the rate of vehicle deceleration or
acceleration which occurs at various points in
the vehicle. This process is pre-emptive in
nature. Deployment should take place in good
time at the start of the collision.
The rate of vehicle deceleration or acceleration
and the direction of the force are essentially
determined by:
Rthe distribution of forces during the collision
Rthe collision angle
Rthe deformation characteristics of the vehicle
Rthe 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 deci-
sive role in the deployment of an air bag. Nor do
Occupant safety57
Safety
Z

merely aids designed to assist driving. You are
responsible for maintaining the distance to the
vehicle in front, for vehicle speed, for braking in
good time, and for staying in lane. 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.
The driving safety systems described only work
as effectively as possible when there is ade-
quate contact between the tires and the road
surface. Pay particular attention to the informa-
tion regarding tires, recommended minimum
tire tread depths etc. in the "Wheels and tires"
section (
Ypage 333).
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)
General information
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.
The ! ABS warning lamp in the instrument
cluster lights up when the ignition is switched
on. It goes out when the engine is running.
ABS works from a speed of about 5 mph
(8 km/h), regardless of road-surface conditions.
ABS works on slippery surfaces, even when you
only brake gently.
Important safety notes
iObserve the "Important safety notes" sec-
tion (Ypage 65).
GWARNING
If ABS is faulty, the wheels could lock when
braking. The steerability and braking charac-
teristics may be severely impaired. Addition-
ally, further driving safety systems are deac-
tivated. There is an increased danger of skid-
ding and accidents.
Drive on carefully. Have ABS checked imme-
diately at a qualified specialist workshop. When ABS is malfunctioning, other systems,
including driving safety systems, will also
become inoperative. Observe the information
on the ABS warning lamp (
Ypage 261) and dis-
play messages which may be shown in the
instrument cluster (
Ypage 231).
Braking
XIf ABS intervenes: continue to depress the
brake pedal vigorously until the braking sit-
uation is over.
XTo make a full brake application: depress
the brake pedal with full force.
If ABS intervenes when braking, you will feel a
pulsing in the brake pedal.
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)
General information
BAS operates in emergency braking situations.
If you depress the brake pedal quickly, BAS
automatically boosts the braking force, thus
shortening the stopping distance.
Important safety notes
iObserve the "Important safety notes" sec-
tion (Ypage 65).
GWARNING
If BAS is malfunctioning, the braking distance
in an emergency braking situation is
increased. There is a risk of an accident.
In an emergency braking situation, depress
the brake pedal with full force. ABS prevents
the wheels from locking.
Braking
XKeep the brake pedal firmly depressed until
the emergency braking situation is over.
ABS prevents the wheels from locking.
The brakes will function as usual once you
release the brake pedal. BAS is deactivated.
66Driving safety systems
Safety

In such cases, Adaptive Brake Assist can:
Rintervene unnecessarily
Rnot intervene
There is a risk of an accident.
Always pay careful attention to the traffic sit- uation and be ready to brake. Terminate the
intervention in a non-critical driving situation.
GWARNING
Adaptive Brake Assist does not react:
Rto people or animals
Rto oncoming vehicles
Rto crossing traffic
Rwhen cornering
As a result, the Adaptive Brake Assist may not
intervene in all critical conditions. There is a
risk of an accident.
Always pay careful attention to the traffic sit- uation and be ready to brake.
Always adapt your speed to suit the prevailing
road and traffic conditions.
Due to the nature of the system, particularly
complicated but non-critical driving conditions
may also cause Brake Assist to intervene.
If adaptive Brake Assist is not available due to a
malfunction in the radar sensor system, the
brake system remains available with full brake
boosting effect and BAS.
ESP®(Electronic Stability Program)
General notes
iObserve the "Important safety notes" sec-
tion (Ypage 65).
ESP
®monitors driving stability and traction, i.e.
power transmission between the tires and the
road surface.
If ESP
®detects that the vehicle is deviating from
the direction desired by the driver, one or more
wheels are braked to stabilize the vehicle. The
engine output is also modified to keep the vehi-
cle on the desired course within physical limits.
ESP
®assists the driver when pulling away on wet or slippery roads. ESP
®can also stabilize
the vehicle during braking.
ETS/4ETS (Electronic Traction System)
iObserve the "Important safety notes" sec-
tion (Ypage 65).
ETS traction control is part of ESP
®. On vehicles
with 4MATIC, 4ETS is part of ESP®.
Traction control brakes the drive wheels indi-
vidually if they spin. This enables you to pull
away and accelerate on slippery surfaces, for
example if the road surface is slippery on one
side. In addition, more drive torque is transfer-
red to the wheel or wheels with traction.
Traction control remains active, even if you
deactivate ESP
®.
Important safety notes
iObserve the "Important safety notes" sec-
tion (Ypage 65).
GWARNING
If ESP
®is malfunctioning, ESP®is unable to
stabilize the vehicle. Additionally, further driv-
ing safety systems are deactivated. This
increases the risk of skidding and an accident.
Drive on carefully. Have ESP
®checked at a
qualified specialist workshop.
When towing the vehicle with the rear axle
raised, observe the notes on ESP
®
(Ypage 329).
If the å ESP®OFF warning lamp lights up
continuously, ESP®is deactivated.
If the ÷ ESP®warning lamp lights up contin-
uously, ESP®is not available due to a malfunc-
tion.
Observe the information on warning lamps
(
Ypage 261) and display messages which may
be shown in the instrument cluster
(
Ypage 231).
Only use wheels with the recommended tire
sizes. Only then will ESP
®function properly.
Driving safety systems69
Safety
Z

Characteristics of ESP®
General information
If the÷ ESP®warning lamp goes out before
beginning the journey, ESP®is automatically
active.
If ESP
®intervenes, the ÷ESP®warning lamp
flashes in the instrument cluster.
If ESP
®intervenes:
XDo not deactivate ESP®under any circum-
stances.
XOnly depress the accelerator pedal as far as
necessary when pulling away.
XAdapt your driving style to suit the prevailing
road and weather conditions.
ECO start/stop function
The ECO start/stop function switches the
engine off automatically when the vehicle stops
moving. The engine starts automatically when
the driver wants to pull away again. ESP
®
remains in its previously selected status, e.g. if
ESP®was deactivated before the engine was
automatically switched off.
Deactivating/activating ESP®(except
Mercedes ‑AMG vehicles)
Important safety notes
iObserve the "Important safety notes" sec-
tion (Ypage 65).
You can select between the following states of
ESP
®:
RESP®is activated.
RESP®is deactivated.
GWARNING
If you deactivate ESP
®, ESP®no longer sta-
bilizes the vehicle. There is an increased risk
of skidding and an accident.
Only deactivate ESP
®in the situations descri-
bed in the following.
It may be best to deactivate ESP
®in the follow-
ing situations:
Rwhen using snow chains
Rin deep snow
Ron sand or gravel Spinning the wheels results in a cutting action
which provides better grip.
iActivate ESP®as soon as the situations
described above no longer apply. ESP®will
otherwise not be able to stabilize the vehicle if
the vehicle starts to skid or a wheel starts to
spin.
!Avoid spinning the driven wheels for an
extended period with ESP®deactivated. You
could otherwise damage the drivetrain.
Deactivating/activating ESP®
You can deactivate or activate ESP®via the on-
board computer (Ypage 222).
ESP®deactivated:
The å ESP®OFF warning lamp in the instru-
ment cluster lights up.
ESP
®activated:
The å ESP®OFF warning lamp in the instru-
ment cluster goes out.
Characteristics when ESP®is deactivated
If ESP®is deactivated and one or more wheels
start to spin, the ÷ESP®warning lamp in the
instrument cluster flashes. In such situations ,
E
SP®will not stabilize the vehicle.
If you deactivate ESP®:
RESP®no longer improves driving stability.
REngine torque is no longer limited and the
drive wheels are able to spin.
RTraction control is still activated.
RActive Brake Assist is no longer available; nor
is it activated if you brake firmly with assis-
tance from ESP
®.
RPRE-SAFE®is no longer available, nor is it
activated if you brake firmly and ESP®inter-
venes.
RPRE-SAFE®Brake is no longer available, it is
also not activated if you brake firmly and ESP®
intervenes.
RESP®still provides support when you brake
firmly.
70Driving safety systems
Safety