2020 MERCEDES-BENZ METRIS warning light

Problem
Possible causes/consequences and
M SolutionsThe PASSENGER AIR
BAG OFF indicator lamp
lights up and remains
lit, even though the
front-passenger seat is
occupied by an adult or
a person of a stature
corresponding to that of
an adult. The classification of the person on the front-passenger seat is incor-
rect.
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 OCS checked as soon as possible at a Mercedes-Benz Com-
mercial Van Center. The PASSENGER AIR
BAG OFF indicator lamp
does not light up
and/or does not stay
on.
The front-passenger
seat is:
R
unoccupied
R occupied by the
weight of a child up
to twelve months old
in a child restraint
system OCS is malfunctioning.
X Make sure there is nothing between the seat cushion and the
child seat.
X Make 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 possi-
ble against the backrest of the front passenger seat. If necessary,
adjust the position of the front-passenger seat.
X When 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.
X Check 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
accordingly.
X Make sure that no objects are applying additional weight onto the
seat.
X If the PASSENGER AIR BAG OFF indicator lamp remains off, do
not install a child restraint system on the front-passenger seat. It
is recommended that you install the child restraint system on a
suitable rear seat.
X Have OCS checked as soon as possible at a Mercedes-Benz Com-
mercial Van Center. Deployment of Emergency Tension-
ing Devices and air bags
Important safety notes G
WARNING
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. G
WARNING
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 spe-
cialist 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
and to have any malfunctioning air bags
repaired. This will help to make sure the air 58
Occupant safety
Safety

bags continue to perform their protective func-
tion for the vehicle occupants in the event of a
crash. G
WARNING
Emergency Tensioning Devices that have
deployed pyrotechnically are no longer
operational and are unable to perform their
intended 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.
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
hearing. The powder that is released generally
does not constitute a health hazard, but it may
cause short-term breathing difficulties in peo-
ple 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 prevent breathing difficulties.
Air bags and pyrotechnic Emergency Tension-
ing Devices (ETDs) contain perchlorate mate-
rial, which may require special handling and
regard for the environment. National guide-
lines must be observed during disposal. In Cal-
ifornia, 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 impor-
tant physical data relating to vehicle decelera-
tion or acceleration, such as:
R duration
R direction
R intensity
Based on the evaluation of this data, the
restraint system control unit triggers the Emer-
gency Tensioning Devices during a head-on or
rear-end collision. An Emergency Tensioning Device can only be
triggered, if:
R the ignition is switched on
R the components of the restraint system are
operational. You can find further information
under "Restraint system warning lamp"
(Y page
46)
R the seat belt buckle tongue has engaged in
the belt buckle of the respective front seat
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:
R Front air bags
R Window curtain air bag, if the system deter-
mines that deployment can offer additional
protection to that provided by the seat belt
Depending on the person in the front-
passenger seat, the front-passenger front air
bag is either enabled or disabled. The front-
passenger front air bag can be deployed in an
accident only if the PASSENGER AIR BAG OFF
indicator lamp is off. Observe the information
on the PASSENGER AIR BAG OFF indicator
lamp (Y page 47).
Your vehicle has two-stage front air bags.
The activation threshold of the Emergency
Tensioning Devices and the air bags is deter-
mined by evaluating the rate of vehicle decel-
eration or acceleration which occurs at various
points in the vehicle. This process is pre-emp-
tive in nature. Deployment 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 collision
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 air bag.
Nor do they provide an indication of air bag
deployment.
The vehicle can be deformed considerably,
without an air bag being deployed. This is the
case if only parts which are relatively easily
deformed are affected and the rate of deceler- Occupant safety
59
Safety Z

ation is not high. Conversely, air bags may be
deployed even though the vehicle suffers only
minor deformation. This is the case if, for
example, very rigid vehicle parts such as longi-
tudinal 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 rolls over, the
applicable components of the restraint system
are deployed independently of each other
depending on the apparent type of accident.
R Side impact air bag and pelvis air bag on the
side on which an impact occurs, independ-
ent from the Emergency Tensioning Device
and seat belt usage
The side impact air bag on the front
passenger side deploys under the following
conditions:
- the OCS system detects that the front
passenger seat is occupied or
- the seat belt buckle tongue is engaged in
the belt buckle of the front passenger
seat
R Window curtain air bag on the side of
impact, independently of the use of the seat
belt and independently of whether the front-
passenger seat is occupied
R Emergency Tensioning Devices, if the sys-
tem determines that deployment can offer
additional protection in this situation
R Window curtain air bags on the driver's and
front-passenger side in certain situations
when the vehicle rolls over, if the system
determines that deployment can offer addi-
tional protection to that provided by the
seat belt
i Not all air bags are deployed in an acci-
dent. The various air bags work independ-
ently of each other.
How the air bag works is determined by the
severity of the accident detected, especially
the vehicle deceleration or acceleration and
the apparent type of accident:
R Head-on collision
R Side impact
R Rollover 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 switched on
R the emergency lighting in the interior is acti-
vated
R the vehicle doors are unlocked
R the front side windows are lowered
R air-recirculation mode is activated
R climate control is switched off
R the engine is switched off and the fuel sup-
ply is cut off Children in the vehicle
Important safety notes
Accident statistics show that children secured
on the rear seats are safer than children
secured on the front seats. For this reason,
Mercedes-Benz strongly advises that you fit
the child restraint system to a rear seat. The
child is generally better protected there.
If a child younger than twelve years old and
under 5 ft
(1.50 m) in height is traveling in the
vehicle:
R always secure the child in a child restraint
system suitable for Mercedes-Benz vehicles.
The child restraint system must be appropri-
ate to the age, weight and size of the child.
R always observe the instructions and safety
notes in this section in addition to the child
restraint system manufacturer's instruc-
tions.
R always observe the instructions and safety
notes on the "Occupant Classification Sys-
tem (OCS)" ( Y page 54). G
WARNING
If children are left unsupervised in the vehi-
cle, they could, in particular:
R open doors, thereby endangering other
persons or road users.
R get out and be struck by oncoming traffic.
R operate vehicle equipment and become
trapped, for example.60
Children in the vehicle
Safety

In addition, children could set the vehicle in
motion, for example, if they:
R release the parking brake.
R change the transmission position.
R start the vehicle.
There is a risk of accident and injury.
Never leave children unsupervised in the
vehicle.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle.
Keep the SmartKey out of the reach of chil-
dren. G
WARNING
If persons, particularly children are subjec-
ted to prolonged exposure to extreme heat
or cold, there is a risk of injury, possibly
even fatal. Never leave children unattended
in the vehicle. G
WARNING
If the child restraint system is subjected to
direct sunlight, parts may get very hot. Chil-
dren may burn themselves on these parts,
particularly on the metal parts of the child
restraint system. There is a risk of injury.
If you leave the vehicle, taking the child with
you, always ensure that the child restraint
system is not exposed to direct sunlight.
Protect it with a blanket, for example. If the
child restraint system has been exposed to
direct sunlight, let it cool down before secur-
ing the child in it. Never leave children unat-
tended in the vehicle.
Make sure that all vehicle occupants have fas-
tened their seat belts properly and are seated
correctly. This is particularly important for chil-
dren.
Observe the safety notes on seat belts
(Y page
48) and the notes on the correct use
of the seat belt (Y page 49).
A booster seat may be necessary to achieve
proper seat belt positioning for children over
40 lbs (18 kg) until they reach a height where
a three-point seat belt fits properly without a
booster seat. Special seatbelt retractor
G
WARNING
If the seat belt is released while driving, the
child restraint system will no longer be
secured properly. The special seat belt
retractor is disabled and the inertia real
draws in a portion of the seat belt. The seat
belt cannot be immediately refastened.
There is an increased risk of injury, possibly
even fatal.
Stop the vehicle immediately, paying atten-
tion to road and traffic conditions. Reacti-
vate the special seat belt retractor and
secure the child restraint system properly.
All seat belts in the vehicle, except the driver's
seat belt, are equipped with a special seat belt
retractor. When activated, the special seat belt
retractor ensures that the seat belt cannot
slacken once the child seat is secured.
Installing a child restraint system:
X Make sure you observe the child restraint
system manufacturer's installation instruc-
tions.
X Pull the seat belt smoothly from the belt
outlet.
X Engage seat belt tongue in belt buckle.
Activating the special seat belt retractor:
X Pull the seat belt out fully and let the inertia
reel retract it again.
While the seat belt is retracting, you should
hear a ratcheting sound. The special seat
belt retractor is enabled.
X Push the child restraint system down so that
the seat belt is tight and does not loosen.
Removing the child restraint system and deac-
tivating the special seat belt retractor:
X Make sure you observe the child restraint
system manufacturer's installation instruc-
tions.
X Press the release button of the seat belt
buckle and guide the seat belt tongue back
towards the belt sash guide.
The special seat belt retractor is deactiva-
ted. Children in the vehicle
61
Safety Z

running from the belt outlet to the belt guide
of the child restraint system. The shoulder belt
strap must be routed forward and down from
the vehicle belt outlet. Adjust the belt outlet
and co-driver's seat as required.
Always comply with the manufacturer's instal-
lation and operating instructions for the child
restraint system. Override feature/child-proof locks
Important safety notes G
WARNING
If children are traveling in the vehicle, they
could in particular:
R open doors, thereby endangering other
persons or road users.
R get out and be struck by oncoming traffic.
R operate vehicle equipment and become
trapped.
There is a risk of an accident and injury.
Always activate the child-proof locks and
override feature if children are traveling in
the vehicle. When leaving the vehicle,
always take the key with you and lock the
vehicle. Never leave children unattended in
the vehicle.
Child-proof lock/override feature for:
R Sliding doors ( Y page
66)G
WARNING
If children are left unsupervised in the vehi-
cle, they could, in particular:
R open doors, thereby endangering other
persons or road users.
R get out and be struck by oncoming traffic.
R operate vehicle equipment and become
trapped, for example.
In addition, children could set the vehicle in
motion, for example, if they:
R release the parking brake.
R change the transmission position.
R start the vehicle. There is a risk of accident and injury.
Never leave children unsupervised in the
vehicle.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle.
Keep the SmartKey out of the reach of chil-
dren.
G
WARNING
If persons, particularly children are subjec-
ted to prolonged exposure to extreme heat
or cold, there is a risk of injury, possibly
even fatal. Never leave children unattended
in the vehicle. G
WARNING
If the child restraint system is subjected to
direct sunlight, parts may get very hot. Chil-
dren may burn themselves on these parts,
particularly on the metal parts of the child
restraint system. There is a risk of injury.
If you leave the vehicle, taking the child with
you, always ensure that the child restraint
system is not exposed to direct sunlight.
Protect it with a blanket, for example. If the
child restraint system has been exposed to
direct sunlight, let it cool down before secur-
ing the child in it. Never leave children unat-
tended in the vehicle. Children in the vehicle
65
Safety Z

ABS (Anti-lock Braking System)
General notes ABS regulates brake pressure in such a way
that the wheels do not lock when you brake.
This allows you to continue steering the vehi-
cle when braking.
The ò warning lamp in the instrument clus-
ter lights up when the ignition is switched on.
The lamp goes out when the engine starts run-
ning.
Important safety notes Observe the important safety guidelines for
the driving safety system (
Y page
66).
ABS works from a speed of about 5 mph
(8 km/h), regardless of road-surface condi-
tions. ABS works on slippery surfaces, even
when you only brake gently. G
WARNING
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
skidding and accidents.
Drive on carefully. Have ABS checked imme-
diately at a qualified specialist workshop.
If ABS is malfunctioning, the ò warning
lamp

(Y page 230) lights up while the engine
is running and the display shows a message:
R on vehicles without steering wheel buttons
(Y page 196)
R on vehicles with steering wheel buttons
(Y page 210)
BAS, Hill Start Assist and ESP ®
and its driving
safety systems and other driving systems also
fail. Observe the notes on the ò warning
lamp and the display messages.
Braking If ABS intervenes when braking, you will feel a
pulsating 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. X
If ABS intervenes: continue to depress the
brake pedal with force until the braking sit-
uation is over.
X To make a full brake application: depress
the brake pedal with full force. BAS (Brake Assist System)
General notes 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 Observe the important safety guidelines for
the driving safety system

(Y page 66). G
WARNING
If BAS is malfunctioning, the braking dis-
tance 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.
If BAS is malfunctioning, the ÷ warning
lamp lights up while the engine is running
(Y page

230) and the display shows a mes-
sage:
R on vehicles without steering wheel buttons
(Y page 200)
R on vehicles with steering wheel buttons
(Y page 214)
Braking X
Keep 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. Driving safety systems
67
Safety Z

EBD (electronic brake force distribu-
tion)
General notes EBD monitors and controls the brake pressure
to the rear wheels. This enables EBD to
improve handling during braking.
Important safety notes Observe the important safety guidelines for
the driving safety system
(Y page 66).G
WARNING
If EBD is malfunctioning, the rear wheels can
lock, e.g. under full braking. This increases
the risk of skidding and an accident.
You should therefore adapt your driving
style to the different handling characteris-
tics. Have the brake system checked at a
qualified specialist workshop.
If EBD is malfunctioning, the $ warning
lamp

(Y page 229) lights up while the engine
is running and the display shows a message:
R on vehicles without steering wheel buttons
(Y page 199)
R on vehicles with steering wheel buttons
(Y page 213)
Other driving systems and driving safety sys-
tems then also fail. ESP
®
(Electronic Stability Program)
General notes ESP
®
monitors driving stability and detects a
tendency of the vehicle to understeer or over-
steer (skidding) in good time. 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 out-
put is also modified to keep the vehicle on the
desired course within physical limits. ESP ®
can
also stabilize the vehicle during braking.
ESP ®
also monitors traction, i.e. power trans-
mission between the tires and the road sur-
face. The integrated traction control supports
you when pulling away or accelerating on wet,
slippery or slick roads. Should the drive
wheels spin, traction control brakes them indi- vidually. In addition, greater drive torque is
transmitted to the wheel or wheels with trac-
tion. If traction on the road surface is not suffi-
cient, even ESP
®
will not allow you to pull
away without difficulty. The type of tires and
total weight of the vehicle as well as the gradi-
ent of the road also play a crucial role. Trac-
tion control remains active if you deactivate
ESP ®
.
If the h warning lamp in the instrument
cluster goes out before beginning the journey,
ESP ®
is automatically active.
The h warning lamp in the instrument clus-
ter flashes when ESP ®
intervenes:
X do not deactivate ESP ®
under any circum-
stances.
X when driving off, apply as little throttle as
possible.
X adapt your speed and driving style to the
prevailing road conditions.
Important safety notes Observe the important safety guidelines for
the driving safety system (
Y page

66). G
WARNING
If ESP ®
is malfunctioning it will not provide
any vehicle stabilization. There is an
increased risk of skidding or of an accident.
Exercise caution when continuing to drive.
Have ESP ®
checked at a qualified specialist
workshop.
! Do not run the vehicle on a roller dyna-
mometer (e.g. for performance tests). If you
must operate the vehicle on a roller dyna-
mometer, please consult a qualified special-
ist workshop in advance. You could other-
wise damage the drive train or the brake
system.
If ESP ®
is malfunctioning, the h warning
lamp

(Y page 230) lights up continuously
while the engine is running and the display
shows a message.
R on vehicles without steering wheel buttons
(Y page 200)
R on vehicles with steering wheel buttons
(Y page 214) 68
Driving safety systems
Safety

ESP
®
is deactivated if the å warning lamp
in the instrument cluster is lit when the engine
is running.
Only use wheels with the recommended tire
sizes. Only then will ESP ®
function properly.
Deactivating or activating ESP ®G
WARNING
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
described in the following.
It may be best to deactivate ESP ®
in the fol-
lowing situations:
R when using snow chains
R in deep snow
R on sand or gravel
Activate ESP ®
as soon as the situations descri-
bed above no longer apply. Otherwise, ESP ®
assistance for stabilizing the vehicle will
remain significantly reduced, even if the vehi-
cle starts to skid.
If you deactivate ESP ®
:
R the å warning lamp in the instrument
cluster lights up
R the ÷ warning lamp in the instrument
cluster flashes if the wheels are spinning
R ESP ®
assistance for stabilizing the vehicle in
the lower speed range up to approximately
37 mph (60 km/h
) is significantly reduced
R engine torque is no longer limited and the
drive wheels are able to spin. The spinning
of the wheels results in a cutting action for
better traction on loose surfaces
R traction control is still activated
R ESP ®
still provides support when you brake
Depending on the equipment in the vehicle,
you can activate or deactivate ESP ®
when the
engine is running by using the å button or
by using the on-board computer:
R on vehicles without steering wheel buttons
(Y page 179)
R on vehicles with steering wheel buttons
(Y page 190) å button (equipment-dependent)
X To activate/deactivate: when the engine
is running, press the å button.
The å warning lamp in the instrument
cluster lights up when ESP ®
is deactivated.
Trailer stabilization Observe the important safety guidelines for
the driving safety system (
Y page

66). G
WARNING
If road and weather conditions are poor,
trailer stabilization will not be able to pre-
vent the vehicle/trailer combination from
swerving. Trailers with a high center of grav-
ity can tip over before ESP ®
can detect this.
There is a risk of an accident.
Always adapt your driving style to the pre-
vailing road and weather conditions.
ESP ®
trailer stabilization counteracts critical
driving situations in good time and thereby
provides considerable assistance when driving
with a trailer. Trailer stabilization is part of
ESP ®
.
If the sensor system and evaluation logic
detect trailer swinging movements, ESP ®
trailer stabilization firstly brakes individual
vehicle wheels in a targeted manner. It thus
counteracts swinging movements. If the
swinging movements do not stop, the vehicle
is braked until the vehicle/trailer combination
is stabilized. If necessary, the vehicle's engine
output is limited.
If your vehicle with trailer (vehicle/trailer com-
bination) starts to swerve, you will be able to
stabilize the vehicle/trailer combination only
by braking. ESP ®
trailer stabilization helps you Driving safety systems
69
Safety Z