MERCEDES-BENZ GLS 2017 Repair Manual

If it is absolutely necessary to carry a child on
the front-passenger seat, be sure to observe the
information on the "Occupant Classification
System (OCS)" ( Y
page 48). There you will also
find information on deactivating the front-
passenger front air bag.
All child restraint systems must meet the fol-
lowing standards: R
U.S. Federal Motor Vehicle Safety Standards
213 and 225 R
Canadian Motor Vehicle Safety Standards
213 and 210.2
Confirmation that the child restraint system cor-
responds to the standards can be found on an
instruction label on the child restraint system.
This confirmation can also be found in the instal-
lation instructions that are included with the
child restraint system.
Observe the warning labels in the vehicle inte-
rior and on the child restraint system.
LATCH-type (ISOFIX) child seat secur-
ing system
G WARNING
LATCH-type (ISOFIX) child restraint systems
do not offer sufficient protective effect for
children whose weight is greater than 48 lbs
(22 kg) who are secured using the safety belt
integrated in the child restraint system. In the
event of an accident, a child might not be
restrained correctly. This poses an increased
risk of injury or even fatal injury.
If the child weighs more than 48 lbs (22 kg),
only use LATCH-type (ISOFIX) child restraint
systems with which the child is also secured
with the vehicle seat belt. Also secure the
child restraint system with the Top Tether
belt, if available.
Always comply with the manufacturer's instal-
lation and operating instructions for the child
restraint system used.
Before every trip, make sure that the LATCH-
type (ISOFIX) child restraint system is engaged
correctly in both LATCH-type (ISOFIX) securing
rings
To ensure that the LATCH-type (ISOFIX) child
restraint system can perform its protective func-
tion as intended, the backrest of the respective outer seat in the second row must be in the
upright position.
! When installing the child restraint system,
make sure that the seat belt for the middle
seat does not get trapped. The seat belt could
otherwise be damaged.
LATCH-type (ISOFIX) securing rings for the outer
seat in the second row of seats
LATCH-type (ISOFIX) securing rings for the third
row of seats
Before installing a LATCH-type (ISOFIX) child
restraint system on the second row of seats: X
Move the rear seat backrests in the second
row to an upright position ( Y
page 98).X
Install the LATCH-type (ISOFIX) child restraint
system on both LATCH-type (ISOFIX) securing
rings C .
ISOFIX is a standardized securing system for
specially designed child restraint systems on
the rear seats.
Non-LATCH-type (ISOFIX) child seats may also
be used and can be installed using the vehicle's
seat belt system. Install the child seat according
to the manufacturer's instructions.Children in the vehicle 59
Safety Z

Top Tether
Introduction Top Tether provides an additional connection
between the child restraint system secured with
a LATCH-type (ISOFIX) system and the vehicle.
This helps reduce the risk of injury even further.
If the child restraint system is equipped with a
Top Tether belt, this should always be used.
Important safety notes
G WARNING
If the rear seats or the rear seat backrests are
not locked, they could fold forwards in the
event of an accident, heavy braking or sudden
changes of direction. As a result, child
restraint systems cannot perform their inten-
ded protective function. Rear seats and rear
seat backrests that are not locked can also
cause additional injuries, e.g. in the event of
an accident. This poses an increased risk of
injury or even fatal injury.
Always lock the rear seats and rear seat
backrests after installing a Top Tether belt.
Observe the lock verification indicator. Adjust
the rear seat backrests so that they are in an
upright position.
Make sure that the backrest in the rear com-
partment engages fully. To do so, pull firmly on
the seat backrest.
Top Tether anchorages
The Top Tether anchorages for the second row
of seats are located on the rear of the rear seat
backrests. For the third row of seats, use the cargo tie-down rings in the cargo compartment
floor.
X
Move head restraint

Child restraint system on the front-
passenger seat
General notes Accident statistics show that children secured
in the rear seats are safer than children secured
in the front-passenger seat. For this reason,
Mercedes-Benz strongly advises that you install
the child restraint system on a rear seat.
If it is absolutely necessary to install a child
restraint system on the front-passenger seat,
always observe the instructions and safety
notes on the "Occupant Classification System
(OCS)" ( Y
page 48).
You can thus avoid the risks that could arise as
a result of: R
an incorrectly categorized person in the front-
passenger seat R
the unintentional deactivation of the front-
passenger front air bag R
the unsuitable positioning of the child
restraint system, e.g. too close to the dash-
board
Rearward-facing child restraint system If it is absolutely necessary to install a rearward-
facing child restraint system on the front-
passenger seat, always make sure that the
front-passenger front air bag is deactivated.
Only if the PASSENGER AIR BAG OFF indicator
lamp is permanently lit ( Y
page 42) is the front-
passenger front air bag deactivated.
Always observe the child restraint system man-
ufacturer's installation and operating instruc-
tions.
Forward-facing child restraint system If it is absolutely necessary to install a forward-
facing child restraint system on the front-
passenger seat, always move the front-
passenger seat as far back as possible. The
entire base of the child restraint system must
always rest on the seat cushion of the front-
passenger seat. The backrest of the child
restraint system must lie as flat as possible
against the backrest of the front-passenger
seat. The child restraint system must not touch
the roof or be subjected to a load by the head
restraint. Adjust the angle of the seat backrest
and the head restraint position accordingly.
Always make sure that the shoulder belt strap is correctly routed from the vehicle belt outlet to
the shoulder belt guide on the child restraint
system. The shoulder belt strap must be routed
forwards and downwards from the vehicle belt
outlet. If necessary, adjust the vehicle belt out-
let and the front-passenger seat accordingly.
Always observe the child restraint system man-
ufacturer's installation and operating instruc-
tions.
Child-proof locks
Important safety notes
G WARNING
If children are traveling in the vehicle, they
could: R
open doors, thus endangering other people
or road users R
exit the vehicle and be caught 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.
Override feature for: R
the rear doors ( Y
page 62) R
the rear side windows ( Y
page 62)
G WARNING
If you leave children unsupervised in the vehi-
cle, they could set it in motion by, for example: R
release the parking brake. R
shift the automatic transmission out of the
parking position P . R
start the engine.
In addition, they may operate vehicle equip-
ment and become trapped. There is a risk of
an accident and injury.Children in the vehicle 61
Safety Z

When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children unsupervised in the vehicle.
G WARNING
If persons, particularly children are subjected
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. Pro-
tect it with a blanket, for example. If the child
restraint system has been exposed to direct
sunlight, let it cool down before securing the
child in it. Never leave children unattended in
the vehicle.
Child-proof locks for the rear doors
You secure each door individually with the child-
proof locks on the rear doors. A door secured
with a child-proof lock cannot be opened from
inside the vehicle. When the vehicle is unlocked,
the door can be opened from the outside. X
To activate: press the child-proof lock lever
up in the direction of arrow C .X
Make sure that the child-proof locks are work-
ing properly. X
To deactivate: press the child-proof lock
lever down in the direction of arrow D .
Override feature for the rear side win-
dows X
To activate/deactivate: press button C .
If indicator lamp D is lit, operation of the rear
side windows is disabled. Operation is only
possible using the switches in the driver's
door. If indicator lamp D is off, operation is
possible using the switches in the rear com-
partment.
Pets in the vehicle
G WARNING
If you leave animals unattended or unsecured
in the vehicle, they could press buttons or
switches, for example.
As a result, they could: R
activate vehicle equipment and become
trapped, for example R
activate or deactivate systems, thereby
endangering other road users
Unsecured animals could also be flung around
the vehicle in the event of an accident or sud-
den steering or braking, thereby injuring vehi-
cle occupants. There is a risk of an accident
and injury.62
Pets in the vehicle
Safety

Never leave animals unattended in the vehi-
cle. Always secure animals properly during
the journey, e.g. use a suitable animal trans-
port box.
Driving safety systems
Overview of driving safety systems In this section, you will find information about
the following driving safety systems: R
ABS ( A nti-lock B raking S ystem)
( Y
page 63) R
BAS ( B rake A ssist S ystem) ( Y
page 64)R
Active Brake Assist ( Y
page 64)R
ESP ®
( E lectronic S tability P rogram)
( Y
page 67) R
EBD ( E lectronic B rake force D istribution)
( Y
page 69) R
ADAPTIVE BRAKE ( Y
page 69)R
Active Brake Assist with cross-traffic function
( Y
page 69) R
STEER CONTROL ( Y
page 72)
Important safety notes If you fail to adapt your driving style or if you are
inattentive, the driving safety systems can nei-
ther reduce the risk of an accident nor override
the laws of physics. Driving safety systems are
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 ( Y
page 346).
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
i Observe the "Important safety notes" sec-
tion ( Y
page 63).
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 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 ( Y
page 277) and dis-
play messages which may be shown in the
instrument cluster ( Y
page 245).
Braking X
If ABS intervenes: continue to depress the
brake pedal vigorously until the braking sit-
uation is over. X
To 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.Driving safety systems 63
Safety Z

Off-road ABS An ABS system specifically suited to off-road
terrain is activated automatically once the off-
road program is activated on: R
Vehicles without the Offroad Engineering
package ( Y
page 217)R
Vehicles with the Off-Road Engineering pack-
age ( Y
page 218)
At speeds below 20 mph (30 km/h), the front
wheels lock cyclically during braking. The dig-
ging-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
i Observe the "Important safety notes" sec-
tion ( Y
page 63).
G WARNING
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 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. Active Brake Assist
General information
i Observe the "Important safety notes" sec-
tion ( Y
page 63).
Active Brake Assist consists of a distance warn-
ing function with an autonomous braking func-
tion and Adaptive Brake Assist.
Active Brake Assist can help you to minimize the
risk of a collision with the vehicle traveling in
front or reduce the effects of such a collision.
If Active Brake Assist detects that there is a risk
of collision, you will be warned visually and
acoustically. If you do not react to the visual and
audible collision warning, autonomous braking
can be initiated in critical situations. If you apply
the brake yourself in a critical situation, Adap-
tive Brake Assist of the Active Brake Assist sys-
tem supports you.
Important safety notes In particular, the detection of obstacles can be
impaired if: R
there is dirt on the sensors or anything else
covering the sensors R
there is snow or heavy rain R
there is interference by other radar sources R
there are strong radar reflections, for exam-
ple in parking garages R
a narrow vehicle is traveling in front, e.g. a
motorbike R
a vehicle is traveling in front on a different line R
new vehicles or after servicing is carried out
on the Active Brake Assist system
Observe the notes in the section on breaking-
in ( Y
page 137).
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 slow
speeds where there is no visible damage to the
front of the vehicle.
Activating/deactivating
Active Brake Assist is automatically active after
switching on the ignition.
You can activate or deactivate Active Brake
Assist ( Y
page 237) in the on-board computer.
When deactivated, the distance warning func-64
Driving safety systems
Safety

tion and the autonomous braking function are
also deactivated.
If Active Brake Assist is deactivated, the

are in the path of your vehicle for an extended
period of time.
If adaptive Brake Assist detects a risk of colli-
sion with the vehicle in front, it calculates the
braking force necessary to avoid a collision. If
you apply the brakes forcefully, adaptive Brake
Assist will automatically increase the braking
force to a level suitable for the traffic conditions.
Adaptive Brake Assist provides braking assis-
tance in hazardous situations at speeds above
4 mph (7 km/h). It uses radar sensor technology
to assess the traffic situation.
Up to a speed of approximately 155 mph
(25 0 km/ h) , Adaptive Brake Assist is capable of
reacting to moving objects that have already
been detected as such at least once over the
period of observation.
Up to a speed of approximately 44 mph
(70 km/ h) , Adaptive Brake Assist reacts to sta-
tionary obstacles.
If adaptive Brake Assist demands particularly
high braking force, preventative passenger pro-
tection measures (PRE-SAFE ®
) are activated
simultaneously ( Y
page 55).X
Keep the brake pedal depressed until the
emergency braking situation is over.
ABS prevents the wheels from locking.
The brakes will work normally again if: R
you release the brake pedal. R
there is no longer any danger of a collision. R
no obstacle is detected in front of your vehi-
cle.
Adaptive Brake Assist is then deactivated.
Important safety notes
i Observe the "Important safety notes" sec-
tion for driving safety systems ( Y
page 63).
G WARNING
Adaptive Brake Assist cannot always clearly
identify objects and complex traffic situa-
tions.
In such cases, Adaptive Brake Assist can: R
intervene unnecessarily R
not 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. G WARNING
Adaptive Brake Assist does not react: R
to people or animals R
to oncoming vehicles R
to crossing traffic R
when 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.
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
i Observe the "Important safety notes" sec-
tion ( Y
page 63).
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)
4ETS traction control 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 ®
.66
Driving safety systems
Safety

In appropriate driving situations, activate the
offroad program: X
Vehicles without the Offroad Engineering
package ( Y
page 217)X
Vehicles with the Off-Road Engineering pack-
age ( Y
page 218)
Offroad 4ETS (Electronic Traction Sys-
tem) An ETS system specifically suited to off-road
terrain is activated automatically once an off-
road program is activated: R
Vehicles without the Offroad Engineering
package ( Y
page 217)R
Vehicles with the Off-Road Engineering pack-
age ( Y
page 218)
Important safety notes
G WARNING
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.
! 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 oth-
erwise 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 only deactivated if the

It may be best to deactivate ESP ®
in the follow-
ing situations: R
when using snow chains R
in deep snow R
on sand or gravel
Spinning the wheels results in a cutting action
which provides better grip.
i Activate 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 ®
X
To deactivate: press button C .
The