2014 MERCEDES-BENZ GL sensor

If the key is removed from the ignition lock or
is in position0, PASSENGER AIRBAG OFF
indicator lampCdoes not light up.
The Occupant Classification System (OCS)
categorizes the occupant on the front-
passenger seat using a weight sensor. The
front-passenger front air bag is deactivated
automatically for certain weight categories.
PASSENGER AIRBAG OFF indicator lampC
shows you the current status. If PASSENGER
AIRBAG OFF indicator lampCis lit, the front-
passenger front air bag is disabled.
The system does not deactivate:
Rthe side impact air bag
Rthe window curtain air bag
Rthe ETDs
To be classified correctly, the front passenger
must sit:
Rwith the seat belt fastened correctly
Rin a position that is as upright as possible
with their back against the seat backrest
Rwith their feet on the floor
The OCS weight sensor reading is affected if
the occupant's weight is transferred, e.g. by
leaning on the armrest.
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.
For safety reasons, Mercedes-Benz
recommends that you only use seat
accessories that have been approved by
Mercedes-Benz.
Both the driver and the front passenger
should always observe the PASSENGER AIR
BAG OFF indicator lamp as an indication of
whether or not the front passenger is
positioned correctly. Observe also the air bag
display messages that can be displayed in the
instrument cluster (Ypage 301).
If the driver's air bag deploys, this does not
mean that the front-passenger front air bag
will also deploy.
The OCS may have detected that the seat:
Ris empty or occupied by the weight of a
typical child up to twelve months old,
seated in a child restraint system.
Ris occupied by a small individual, such as a
young teenager or a small adult.
Ris occupied by a child in a child restraint
system whose weight is greater than that
of a typical twelve month old child.
These are examples of when the OCS
deactivates the front-passenger front air bag.
Deactivation takes place although the
collision fulfills the criteria for deploying the
driver's air bag.
System self-test
GWARNING
If thestindicator lamp does not
illuminate, the system is not functioning. You
must contact an authorized Mercedes-Benz
Center before seating any child on the front
passenger seat.
GWARNING
Objects between the seat surface and the
child restraint system could affect the
function of the OCS. This could result in the
front-passenger front 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. Make
sure that the bottom and back of the child
restraint system make full contact with the
front-passenger seat cushion and backrest.
Occupant safety51
Safety
Z

ProblemPossible causes/consequences andPPSolutions
The PASSENGER AIR
BAG OFF indicator
lamp does not light up
and/or stays on.
The front-passenger
seat is:
Runoccupied
Roccupied with the
weight of a child up
to twelve months old
in a child restraint
system
The OCS is malfunctioning.
XMake sure there is nothing between the seat cushion and the
child seat.
XMake sure that the backrest and base of the child restraint
system are resting securely on the front-passenger seat. If
necessary, adjust the position of the front-passenger seat.
XWhen installing the child restraint system, make sure that the
seat belt is tight. Do not pull the seat belt tight with the front-
passenger seat adjustment. This could result in the seat belt
being pulled too tightly.
XCheck the installation of the child restraint system.
XMake sure that no objects are applying additional weight onto
the seat.
XIf the PASSENGER AIR BAG OFF indicator lamp remains off, have
the OCS system checked as soon as possible at a qualified
specialist workshop. Do not transport a child on the front-
passenger seat until the OCS has been repaired.
XObserve the additional display messages in the multifunction
display (Ypage 301).
PRE-SAFE®(anticipatory occupant
protection system)
Introduction
PRE-SAFE®takes preemptive measures to
protect occupants in certain hazardous
situations.
Important safety notes
!Make sure that there are no objects in the
footwell or behind the seats when resetting
the seats. There is a risk that the seats
and/or the objects could be damaged.
Despite your vehicle being equipped with the
PRE-SAFE®system, the possibility of
personal injuries occurring as a result of an
accident cannot be eliminated.
Always adapt your driving style to suit the
prevailing road and weather conditions and
maintain a safe distance from the vehicle in
front. Drive carefully.
Function
PRE-SAFE®intervenes:
Rin emergency braking situations, e.g. when
BAS is activated.
Rin critical driving situations, e.g. when
physical limits are exceeded and the
vehicle understeers or oversteers severely.
Ron vehicles with DISTRONIC PLUS:if
BAS PLUS brakes hard or the radar sensor
system detects an imminent danger of
collision in certain situations.
PRE-SAFE®takes the following measures
depending on the hazardous situation
detected:
Rthe front seat belts are pre-tensioned.
Rif the vehicle skids, the sliding sunroof and
the side windows are closed so that only a
small gap remains. On vehicles with a
panorama roof with power tilt/sliding
panel, they are closed completely.
54Occupant safety
Safety

The pulsating brake pedal can be an
indication of hazardous road conditions, and
functions as a reminder to take extra care
while driving.
Off-road ABS
An ABS system specifically suited to off-road
terrain is activated automatically once the off-
road program is activated (Ypage 258).
At speeds below 20 mph (30 km/h), the front
wheels lock cyclically during braking. The
digging-in effect achieved in the process
reduces the stopping distance on off-road
terrain. This limits steering capability.
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"
section (Ypage 67).
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.
BAS PLUS (Brake Assist System
PLUS)
General information
iObserve the "Important safety notes"
section (Ypage 67).
BAS PLUS is only available in vehicles
equipped with DISTRONIC PLUS.
For BAS PLUS to assist you, the radar sensor
system must be operational.
With the help of the radar sensor system, BAS
PLUS can detect obstacles that are in the
path of your vehicle for an extended period of
time.
If the radar sensor system is malfunctioning,
BAS PLUS will not be available. The brake
system is still available with complete brake
boosting effect and BAS.
BAS PLUS can help you to minimize the risk
of a collision with a vehicle or reduce the
effects of such a collision. If BAS PLUS
detects a danger of collision, you are assisted
when braking.
Important safety notes
GWARNING
BAS PLUS cannot always clearly identify
objects and complex traffic situations.
In such cases, BAS PLUS may:
Rintervene unnecessarily
Rnot intervene
There is a risk of an accident.
Always pay careful attention to the traffic
situation and be ready to brake. Terminate the
intervention in a non-critical driving situation.
GWARNING
BAS PLUS does not react:
Rto people or animals
Rto oncoming vehicles
Rto crossing traffic
Rwhen cornering
68Driving safety systems
Safety

As a result, BAS PLUS may not intervene in all
critical situations. There is a risk of an
accident.
Always pay careful attention to the traffic
situation and be ready to brake.
In the event of snowfall or heavy rain, the
recognition can be impaired.
Recognition by the radar sensor system is
also impaired in the event of:
Rdirt on the sensors or anything else
covering the sensors
Rthere is interference by other radar sources
Rthere are strong radar reflections, for
example in parking garages
Ra narrow vehicle traveling in front, e.g. a
motorbike
Ra vehicle traveling in front on a different line
relative to the center of your vehicle
Following damage to the front end of the
vehicle, have the configuration and operation
of the radar sensors checked at a qualified
specialist workshop. This also applies to
collisions at low speeds where there is no
visible damage to the front of the vehicle.
Function
To avoid a collision, BAS PLUS calculates the
brake force necessary if:
Ryou approach an obstacle, and
RBAS PLUS has detected a risk of collision
When driving at a speed under 20 mph
(30 km/h): if you depress the brake pedal,
BAS PLUS is activated. The increase in brake
pressure will be carried out at the last
possible moment.
When driving at a speed above 20 mph
(30 km/h): if you depress the brake pedal
sharply, BAS PLUS automatically raises the
brake pressure to a value adapted to the
traffic situation.
BAS PLUS provides braking assistance in
hazardous situations with vehicles in front
within a speed range between 4 mph
(7 km/h) and 155 mph (250 km/h).
At speeds of up to approximately 40 mph
(70 km/h), BAS PLUS can also react to
stationary objects. Examples of stationary
objects are stopped or parked vehicles.
iIf BAS PLUS demands particularly high
braking force, preventative passenger
protection measures (PRE-SAFE®) are
activated simultaneously.
XKeep the brake pedal depressed until the
emergency braking situation is over.
ABS prevents the wheels from locking.
BAS PLUS is deactivated and the brakes
function as usual again, if:
Ryou release the brake pedal.
Rthere is no longer a risk of collision.
Rno obstacle is detected in front of your
vehicle.
If you have activated DSR (Ypage 256), BAS
PLUS is likewise deactivated.
COLLISION PREVENTION ASSIST
General notes
COLLISION PREVENTION ASSIST consists of
Adaptive Brake Assist and the distance
warning function, which are described in the
following.
Distance warning function
Important safety notes
iObserve the "Important safety notes"
section (Ypage 67).
GWARNING
The distance warning function does not react:
Rto people or animals
Rto oncoming vehicles
Rto crossing traffic
Rwhen cornering
Driving safety systems69
Safety
Z

Adaptive Brake Assist
iObserve the "Important safety notes"
section (Ypage 67).
GWARNING
Adaptive Brake Assist cannot always clearly
identify objects and complex traffic
situations.
In such cases, Adaptive Brake Assist may:
Rintervene unnecessarily
Rnot intervene
There is a risk of an accident.
Always pay careful attention to the traffic
situation 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
Rto stationary obstacles
Rwhen cornering
As a result, Adaptive Brake Assist may not
intervene in all critical conditions. There is a
risk of an accident.
Always pay careful attention to the traffic
situation and be ready to brake.
Due to the nature of the system, particularly
complicated but non-critical driving
conditions may also cause Brake Assist to
intervene.
Adaptive Brake Assist aids you in braking
during hazardous situations at speeds above
4 mph (7 km/h) and uses the radar sensor
system to evaluate the traffic situation.
With the help of Adaptive Brake Assist, the
distance warning signal can detect obstacles
that are in the path of your vehicle for an
extended period of time.
Should you approach an obstacle and
Adaptive Brake Assist has detected a risk of
collision, Adaptive Brake Assist calculates the
braking force necessary to avoid a rear-end
collision. Should you apply the brakes
vigorously, Adaptive Brake Assist will
automatically increase the braking force to a
level suitable for the traffic conditions.
XKeep the brake pedal depressed until the
emergency braking situation is over.
ABS prevents the wheels from locking.
The brakes will work normally again if:
Ryou release the brake pedal.
Rthere is no longer any danger of a collision.
Rno obstacle is detected in front of your
vehicle.
Adaptive Brake Assist is then deactivated.
Vehicles with PRE-SAFE®:if adaptive Brake
Assist requires particularly high brake
pressure, preventive passenger protection
measures (PRE-SAFE®) are deployed
simultaneously.
Up to vehicle speeds of around 155 mph
(250 km/h), adaptive Brake Assist is capable
of reacting to moving objects that have
already been recognized as such at least once
over the period of observation. Adaptive
Brake Assist does not react to stationary
obstacles.
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.
In particular, the detection of obstacles can
be impaired if there is:
Rdirt on the sensors or anything else
covering the sensors
Rthere is snow or heavy rain
Rthere is interference by other radar sources
Rthere are strong radar reflections, for
example in parking garages
Ra narrow vehicle traveling in front, e.g. a
motorbike
Driving safety systems71
Safety
Z

Ra vehicle traveling in front on a different line
relative to the center of your vehicle
Rnew vehicles or after the COLLISION
PREVENTION ASSIST system has been
serviced
Observe the notes in the section on
breaking-in (Ypage 166).
Following damage to the front end of the
vehicle, have the configuration and operation
of the radar sensor checked at a qualified
specialist workshop. This also applies to
collisions at low speeds where there is no
visible damage to the front of the vehicle.
ESP®(Electronic Stability Program)
General notes
iObserve the "Important safety notes"
section (Ypage 67).
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 vehicle 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.
4ETS (Electronic Traction System)
4ETS traction control is part of ESP®.
Traction control brakes the drive wheels
individually 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
transferred to the wheel or wheels with
traction.
Traction control remains active, even if you
deactivate ESP®.
In appropriate driving situations, activate the
off-road program (Ypage 258).
Off-road 4ETS (Electronic Traction
System)
A 4ETS system specifically suited to off-road
terrain is activated automatically once the off-
road program is activated (Ypage 258).
Important safety notes
GWARNING
If ESP®is malfunctioning, ESP®is unable to
stabilize the vehicle. Additionally, further
driving safety systems are deactivated. This
increases the risk of skidding and an accident.
Drive on carefully. Have ESP®checked at a
qualified specialist workshop.
!Only operate the vehicle for a maximum
of ten seconds on a brake test
dynamometer. Switch off the ignition.
Application of the brakes by ESP®may
otherwise destroy the brake system.
!A function or performance test should
only be carried out on a two-axle
dynamometer. Before you operate the
vehicle on such a dynamometer, please
consult a qualified workshop. You could
otherwise damage the drive train or the
brake system.
ESP®is deactivated if the

You should therefore adapt your driving style
to the different handling characteristics. Have
the brake system checked at a qualified
specialist workshop.
Observe information regarding indicator and
warning lamps (Ypage 327) as well as
display messages (Ypage 293).
ADAPTIVE BRAKE
ADAPTIVE BRAKE enhances braking safety
and offers increased braking comfort. In
addition to the braking function, ADAPTIVE
BRAKE also has the HOLD function
(Ypage 216) and hill start assist
(Ypage 171).
PRE-SAFE®Brake
General information
iObserve the "Important safety notes"
section (Ypage 67).
PRE-SAFE®Brake is only available in vehicles
with DISTRONIC PLUS.
For PRE-SAFE®Brake to assist you when
driving, the radar sensor system must be
operational.
With the help of the radar sensor system,
PRE-SAFE®Brake can detect obstacles that
are in front of your vehicle for an extended
period of time.
PRE-SAFE®Brake can help you to minimize
the risk of a collision with a vehicle ahead, and
reduce the effects of such a collision. If PRE-
SAFE®Brake has detected a risk of collision,
you will be warned visually and acoustically
as well as by automatic braking. PRE-SAFE®
Brake cannot prevent a collision without your
intervention.
Important safety notes
GWARNING
PRE-SAFE®Brake will initially brake your
vehicle by a partial application of the brakes
if a danger of collision is detected. There may
be a collision unless you also brake.
Automatic emergency braking cannot prevent
a collision. There is a risk of an accident.
Always apply the brakes yourself and try to
take evasive action.
GWARNING
PRE-SAFE®Brake cannot always clearly
identify objects and complex traffic
conditions.
In these cases, PRE-SAFE®Brake may:
Rgive an unnecessary warning and then
brake the vehicle
Rnot give a warning or intervene
There is a risk of an accident.
Always pay particular attention to the traffic
situation and be ready to brake, especially if
PRE-SAFE®Brake warns you. Terminate the
intervention in a non-critical driving situation.
In order to maintain the appropriate distance
to the vehicle in front and thus prevent a
collision, you must apply the brakes yourself.
GWARNING
PRE-SAFE®Brake does not react:
Rto people or animals
Rto oncoming vehicles
Rto crossing traffic
Rwhen cornering
As a result, PRE-SAFE®Brake may neither
give warnings nor intervene in all critical
situations. There is a risk of an accident.
Always pay careful attention to the traffic
situation and be ready to brake.
In the event of snowfall or heavy rain, the
recognition can be impaired.
Driving safety systems75
Safety
Z

Recognition by the radar sensor system is
also impaired in the event of:
Rdirt on the sensors or anything else
covering the sensors
Rthere is interference by other radar sources
Rthere are strong radar reflections, for
example in parking garages
Ra narrow vehicle traveling in front, e.g. a
motorbike
Ra vehicle traveling in front on a different line
relative to the center of your vehicle
Following damage to the front end of the
vehicle, have the configuration and operation
of the radar sensors checked at a qualified
specialist workshop. This also applies to
collisions at low speeds where there is no
visible damage to the front of the vehicle.
Function
XTo activate/deactivate:activate or
deactivate PRE-SAFE®Brake in the on-
board computer (Ypage 281).
If the PRE-SAFE®Brake is not activated, the