2017 MERCEDES-BENZ GLS brakes

! 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.
i In wintry driving conditions, the maximum
effect of 4MATIC can only be achieved if you
use winter tires (M+S tires), with snow chains
if necessary.
Further information about "Driving off-road"
( Y
page 168).
DSR (Downhill Speed Regulation) General notes DSR is an aid to assist you when driving down-
hill. It keeps the speed of travel at the speed
selected on the on-board computer. The steeper
the downhill gradient, the greater the DSR brak-
ing effect on the vehicle. When driving on flat
stretches of road or on an uphill gradient, the
DSR braking effect is minimal or nonexistent.
DSR controls the vehicle’s speed when it is acti-
vated and the transmission is in position D , R or
N . You can drive at a higher or a lower speed
than that set on the on-board computer at any
time by accelerating or braking.
Important safety notes
G WARNING
If the speed driven and the set speed deviate
and you activate DSR on a slippery road sur-
face, the wheels may lose traction. There is an
increased danger of skidding and accidents.
Before switching DSR on, please take into
consideration the road surface and the differ-
ence between driving speed and the set
speed.
If you fail to adapt your driving style, DSR can
neither reduce the risk of accident nor override
the laws of physics. DSR cannot take account of
road, weather and traffic conditions. DSR is only
an aid. You are responsible for the distance to
the vehicle in front, for vehicle speed, for brak-
ing in good time and for staying in your lane.
You are always responsible for keeping control
of the vehicle and for assessing whether the
downhill gradient can be managed. DSR may not
always be able to keep to the set speed, depend- ing on road surface and tire conditions. Select a
set speed suitable for the prevailing conditions
and when necessary, apply the brakes manually.
Activating DSR X
Press button C .
Indicator lamp D lights up.
The

R
Do not install hired trailer couplings or other
detachable trailer couplings on the bumpers
of your vehicle. R
If you no longer need the ball coupling,
remove it from the ball coupling recess. This
will reduce the risk of damage to the ball cou-
pling.
When towing a trailer, set the tire pressure on
the rear axle of the towing vehicle for the max-
imum load. You will find the values in the tire
pressure table in the fuel filler flap of the vehicle
( Y
page 364).
Please note that when towing a trailer, the fol-
lowing driving systems have limited availability
or are not available at all: R
Parking Assist PARKTRONIC ( Y
page 190)R
Blind Spot Assist ( Y
page 207)R
Active Lane Keeping Assist ( Y
page 213)
On vehicles without level control, the height of
the ball coupling will alter according to the load
placed on the vehicle. If necessary, use a trailer
with a height-adjustable drawbar.
You will find installing dimensions and loads
under "Technical data" ( Y
page 387).
Driving tips Observe the information on ESP ®
trailer stabili-
zation ( Y
page 68) and on pulling away with a
trailer ( Y
page 141).
The maximum permissible speed for vehicle/
trailer combinations depends on the type of
trailer. Before beginning the journey, check the
trailer's documents to see what the maximum
permissible speed is. Observe the legally pre-
scribed maximum speed in the relevant country.
For certain Mercedes-Benz vehicles, the maxi-
mum permissible rear axle load is increased
when towing a trailer. See "Technical data" to
find out whether this applies to your vehicle
( Y
page 387). If you utilize any of the added
maximum rear axle load when towing a trailer,
the vehicle/trailer combination may not exceed
a maximum speed of 60 mph (100 km/h) for
reasons concerning the operating permit. This
also applies in countries in which the permissi-
ble maximum speed for vehicle/trailer combi-
nations is above 60 mph (100 km/h).
When towing a trailer, your vehicle's handling
characteristics will be different in comparison
with when driving without a trailer. Use the left-hand steering wheel paddle shifter
to shift into a lowe r g ear in good time on long
a
nd steep downhill gradients.
This also applies if you have activated cruise
control or Distance Pilot DISTRONIC.
This will use the braking effect of the engine, so
that less braking will be required to maintain the
speed. This relieves the load on the brake sys-
tem and prevents the brakes from overheating
and wearing too quickly. If you need additional
braking, depress the brake pedal repeatedly
rather than continuously.
Driving tips If the trailer swings from side to side: X
Do not accelerate. X
Do not counter-steer. X
Brake if necessary. R
Maintain a greater distance from the vehicle
in front than when driving without a trailer. R
Avoid braking abruptly. If possible, brake gen-
tly at first to allow the trailer to run on. Then,
increase the braking force rapidly. R
The values given for gradient-climbing capa-
bilities from a standstill refer to sea level.
When driving in mountainous areas, note that
the power output of the engine and, conse-
quently, the vehicle's gradient-climbing capa-
bility, decreases with increasing altitude.
Installing the ball coupling
G WARNING
If the ball coupling is not correctly installed
and secured, it can come loose during the
journey and endanger other road users. There
is a risk of an accident and injury.
Always install and secure the ball coupling as
described. Before every journey, ensure that
the ball coupling is secured with the bolt and
the corresponding spring cotter.
G WARNING
If the ball coupling is not installed correctly or
not secured with the bolt provided and the
corresponding spring cotter, the trailer may
come loose. There is a risk of an accident.Towing a trailer 223
Driving an d parking Z

Towing a trailer There are numerous legal requirements con-
cerning the towing of a trailer, e.g. speed restric-
tions. Make sure that your car/trailer combina-
tion complies with the local regulations: R
in your place of residence R
in the location to which you are driving
The police and local authorities can provide reli-
able information.
Observe the following when towing a trailer: R
To gain driving experience and to become
accustomed to the new handling characteris-
tics, you should practice the following in a
traffic-free location: -
cornering -
stopping -
backing up R
Before driving, check: -
trailer tow hitch -
safety switch for braked trailers -
safety chains -
electrical connections -
lights -
wheels R
Adjust the exterior mirrors to provide an
unobstructed view of the rear section of the
trailer. R
If the trailer has electronically controlled
brakes, pull away carefully. Brake manually
using the brake controller and check whether
the brakes function correctly. R
Secure any objects on the trailer to prevent
the cargo from slipping when the vehicle is in
motion. R
When you couple up a trailer, check at regular
intervals that the load is firmly secured. If the
tra i ler is equipped with trailer lights and
brakes, check the trailer to ensure that these
are working. R
Bear in mind that the handling will be less
stable when towing a trailer than when driving
without one. Avoid sudden steering move-
ments. R
The vehicle/trailer combination is heavier,
accelerates more slowly, has a decreased
gradient climbing capability and a longer
braking distance.
It is more susceptible to side winds and
requires more careful steering. R
If possible, do not brake suddenly, but instead
depress the brake pedal moderately at first so
that the trailer can activate its brakes. Then
increase the pressure on the brake pedal. R
If the automatic transmission repeatedly
shifts between gears on uphill or downhill gra-
dients, shift to a lower gear using the left-hand
steering wheel paddle shifter.
A lower gear and lower speed reduce the risk
of engine failure. R
When driving downhill, shift to a lower gear to
utilize the engine's braking effect.
Avoid continuous brake application as this
may overheat the vehicle brakes and, if instal-
led, the trailer brakes. R
If the coolant temperature increases dramat-
i cally while the air-conditioning system is
switched on, switch off the air-conditioning
system.
Coolant heat can also be dissipated by open-
ing the windows and switching the ventilation
blower and the interior temperature to the
highest level. R
When overtaking, pay particular attention to
the extended length of your vehicle/trailer
combination.
Due to the length of the vehicle/trailer com-
bination, you require additional road space in
relation to the vehicle you are overtaking
before you can change back to the original
lane.
Decoupling a trailer
G WARNING
If you uncouple a trailer with the overrun
brake engaged, you could trap your hand
between the vehicle and the trailer drawbar.
There is a risk of injury.
Do not uncouple a trailer if the overrun brake
is engaged.
G WARNING
Vehicles with level control:
The vehicle is lowered as soon as you discon-
nect the trailer cable. This could result in your
limbs or those of other people that are
between the vehicle body and tires or under-226
Towing a trailer
Driving an d parking

obtained at a qualified specialist workshop, e.g.
an authorized Mercedes-Benz Center.
Driving abroad An extensive Mercedes-Benz Service network is
also available in other countries. You can obtain
further information from any authorized
Mercedes-Benz Center.
Care
General notes
H Environmental note
Dispose of empty packaging and cleaning
cloths in an environmentally responsible man-
ner.
! For cleaning your vehicle, do not use any of
the following: R
dry, rough or hard cloths R
abrasive cleaning agents R
solvents R
cleaning agents containing solvents
Do not scrub.
Do not touch the surfaces or protective films
with hard objects, e.g. a ring or ice scraper.
You could otherwise scratch or damage the
surfaces and protective film.
! Do not park your vehicle for a long period of
time directly after cleaning, particularly after
cleaning the wheel rim with wheel cleaner.
Wheel cleaner can lead to the increased cor-
rosion of the brake discs and pads. Therefore,
drive for a few minutes after cleaning. By
heating up the brakes, the brake discs and
pads dry. The vehicle can then be parked for a
long period of time.
Regular care of your vehicle is a condition for
retaining the quality in the long term.
Use care products and cleaning agents recom-
mended and approved by Mercedes-Benz. Washing the vehicle and cleaning the
paintwork
Automatic car wash
G WARNING
Braking efficiency is reduced after washing
the vehicle. There is a risk of an accident.
After the vehicle has been washed, brake
carefully while paying attention to the traffic
conditions until full braking power is restored.
! Before driving into an automatic car wash,
make sure that it is suitable for the dimen-
sions of the vehicle. In particular, make sure
that: R
there is enough ground clearance between
the vehicle underbody and the guide rails of
the automatic car wash. R
the clearance width of the automatic car
wash is sufficient, particularly the width of
the guide rails. R
you enter the automatic car wash straight
and in the center of the guide rails in order
to avoid damaging the tires or wheel rims.
Fold in the exterior mirrors before the vehicle
is washed. The exterior mirrors could other-
wise be damaged.
! When DISTRONIC PLUS or the HOLD func-
tion is activated, the vehicle brakes automat-
ically in certain situations.
To avoid damage to the vehicle, deactivate
DISTRONIC PLUS and the HOLD function in
the following or similar situations: R
when towing the vehicle R
in the car wash
! Never clean your vehicle in a Touchless
Automatic Car Wash as these use special
cleaning agents. These cleaning agents can
damage the paintwork or plastic parts.
! Make sure that: R
the side windows and the sliding sunroof
are fully closed. R
the ventilation/heating is switched off (the
OFF button has been pressed). R
the windshield wiper switch is in position 0 .
Otherwise, the vehicle might be damaged.324
Care
Maintenance and care

! Do not park your vehicle for a long period of
time directly after cleaning, particularly after
cleaning the wheel rim with wheel cleaner.
Wheel cleaner can lead to the increased cor-
rosion of the brake discs and pads. Therefore,
drive for a few minutes after cleaning. By
heating up the brakes, the brake discs and
pads dry. The vehicle can then be parked for a
long period of time.
Cleaning the windows
G WARNING
You could become trapped by the windshield
wipers if they start moving while cleaning the
windshield or wiper blades. There is a risk of
injury.
Always switch off the windshield wipers and
the ignition before cleaning the windshield or
wiper blades.
! Do not use dry cloths, abrasive products,
solvents or cleaning agents containing sol-
vents to clean the inside of the windows. Do
not touch the insides of the windows with
hard objects, e.g. an ice scraper or ring. There
is otherwise a risk of damaging the windows.
! Clean the water drainage channels of the
windshield and the rear window at regular
intervals. Deposits such as leaves, petals and
pollen may under certain circumstances pre-
vent water from draining away. This can lead
to corrosion damage and damage to elec-
tronic components. X
Clean the inside and outside of the windows
with a damp cloth and a cleaning product that
is recommended and approved by Mercedes-
Benz.
Cleaning wiper blades
G WARNING
You could become trapped by the windshield
wipers if they start moving while cleaning the
windshield or wiper blades. There is a risk of
injury.
Always switch off the windshield wipers and
the ignition before cleaning the windshield or
wiper blades. ! Do not pull the wiper blade. Otherwise, the
wiper blade could be damaged.
! Do not clean wiper blades too often and do
not rub them too hard. Otherwise, the graph-
ite coating could be damaged. This could
cause wiper noise.
! Hold the wiper arm securely when folding
back. The windshield could be damaged if the
wiper arm smacks against it suddenly. X
Fold the windshield wiper arms away from the
windshield ( Y
page 120). X
Carefully clean the wiper blades with a damp
cloth. X
Fold the windshield wiper arms back again
before switching on the ignition.
Cleaning the exterior lighting
! Only use cleaning agents or cleaning cloths
which are suitable for plastic light lenses.
Unsuitable cleaning agents or cleaning cloths
could scratch or damage the plastic light len-
ses. X
Clean the plastic lenses of the exterior light-
ing using a wet sponge and a mild cleaning
agent, e. g. Mercedes-Benz car shampoo or
cleaning cloths.
Cleaning the mirror turn signals
! Only use cleaning agents or cleaning cloths
that are suitable for plastic lenses. Unsuitable
cleaning agents or cleaning cloths could
scratch or damage the plastic lenses of the
mirror turn signals. X
Clean the plastic lenses of the mirror turn sig-
nals in the exterior mirror housing using a wet
sponge and mild cleaning agent, e.g.
Mercedes-Benz car shampoo or cleaning
cloths.
Cleaning the side running board
! Do not clean the aluminum inserts of the
side running board with alkaline or acidic
cleaners, such as wheel cleaner. Do not use
acidic wheel cleaners to remove brake dust.
The aluminum inserts could otherwise be
damaged. Care 327
Maintenance and care Z

i Jumper cables and further information regarding jump-starting can be obtained at any qualified
specialist workshop.
Towing and tow-starting
Important safety notes
G WARNING
Functions relevant to safety are restricted or
no longer available if: R
the engine is not running. R
the brake system or the power steering is
malfunctioning. R
there is a malfunction in the voltage supply
or the vehicle's electrical system.
If your vehicle is being towed, much more
force may be necessary to steer or brake.
There is a risk of an accident.
In such cases, use a tow bar. Before towing,
make sure that the steering moves freely.
G WARNING
When towing or tow-starting another vehicle
and its weight is greater than the permissible
gross weight of your vehicle, the: R
the towing eye could detach itself R
the vehicle/trailer combination could roll-
over.
There is a risk of an accident.
When towing or tow-starting another vehicle,
its weight should not be greater than the per-
missible gross weight of your vehicle.
Details on the permissible gross vehicle weight
of your vehicle can be found on the vehicle iden-
tification plate ( Y
page 377).
! When Active Brake Assist, Distance Pilot
DISTRONIC or the HOLD function is activated,
the vehicle brakes automatically in certain
situations.
To avoid damage to the vehicle, deactivate
these systems in the following or similar sit-
uations: R
when towing the vehicle R
in the car wash ! Make sure that the electric parking brake is
released. If the electric parking brake is faulty,
visit a qualified specialist workshop.
! Only secure the tow rope or tow bar at the
towing eyes, or the trailer tow hitch, if availa-
ble. You could otherwise damage the vehicle.
! Observe the following points when towing
with a tow rope: R
Secure the tow rope on the same side on
both vehicles. R
Ensure that the tow cable is not longer than
legally permitted. Mark the tow cable in the
middle, e.g. with a white c loth (30 x 30
cm).
This will make other road users aware that
the vehicle is being towed. R
Only secure the tow cable to the towing
eye. R
Observe the brake lamps of the towing
vehicle while driving. Always maintain a dis-
tance so that the tow rope does not sag. R
Do not use steel cables or chains to tow
your vehicle. You could otherwise damage
the vehicle.
! Do not use the trailer tow hitch for recovery
or towing. Do not use the towing eye for
recovery. this could damage the vehicle. If in
doubt, have the vehicle recovered using a
crane.
! When towing, pull away slowly and
smoothly. Pull the towed vehicle as straight as
possible and not at an acute angle. Excessive
tractive power could damage the vehicles.
When towing, it is preferable to use a rigid tow-
ing bar as opposed to a tow rope. A rigid towing
bar helps to keep the tractive power low.
! When towing vehicles with KEYLESS-GO,
use the key instead of the Start/Stop button.
Otherwise, the automatic transmission may
shift to position P when the driver's or front-
passenger door are opened, which could lead
to damage to the transmission.
! Do not tow with sling-type equipment. This
could damage the vehicle.
! Vehicles with differential locks: make sure
the differential locks are in automatic mode.Towing and tow-starting 341
Breakdown assistance Z

Important safety notes
G WARNIN G
If wheels and tires of th e wrong siz e are used,
th e whee l brakes or suspension component s
may be damaged. Ther e is a ris k of an acci-
dent.
Always replace wheels and tires wit h those
that fulfill th e specification s of th e original
part .
When replacing wheels, mak e sur e to use th e
correct: R
designation R
model
When replacing tires , mak e sur e to use th e
correct: R
designation R
manufacturer R
model
G WARNIN G
A flat tire severely impairs th e driving , steer -
ing and braking characteristics of th e vehicle.
Ther e is a ris k of accident.
Tires without run-flat characteristics :R
do no t driv e wit h a flat tire.R
immediately replace th e flat tire wit h your
emergenc y spar e whee l or spar e wheel, or
consult a qualified specialist workshop.
Tires wit h run-flat characteristics :R
pay attention to th e information and warn -
ing notice s on MOExtended tires (tire s wit h
run-flat characteristics).
Accessories that are no t approve d for your vehi-
cle by Mercedes-Ben z or are no t bein g used cor-
rectl y can impair th e operating safety.
Before purchasing and usin g non-approve d
accessories, visit a qualified specialist work-
sho p and inquire about :R
suitabilit yR
legal stipulation sR
factory recommendation s Further information regarding wheels and tires
can be foun d under "Wheel/tire combinations"
( Y
page 371).
You can ask for information regarding permitte d
wheel-tire combination s at an authorize d
Mercedes-Ben z Center.
Tir e pressur e information can be found: R
on th e Tir e and Loading Information placard
on th e B-pillar on th e driver' s sideR
in th e tire pressur e table in th e fuel filler flapR
in th e "Tir e p ressure" section
Operation
Information on driving Chec k th e tire pressur e when th e vehicl e is
heavily laden and adjust prio r to a trip.
While driving , pay attention to vibrations, noises
and unusual handlin g characteristics , e.g. pull-
ing to on e side . This may indicat e that th e
wheels or tires are damaged. If you suspec t that
a tire is defective, reduce your spee d immedi-
ately. Stop th e vehicl e as soo n as possible to
chec k th e wheels and tires for damage. Hidden
tire damag e could also be causing th e unusual
handlin g characteristics . If you fin d no sign s of
damage, hav e th e tires and wheels checke d at a
qualified specialist workshop.
When parking your vehicle, mak e sur e that th e
tires do no t get deformed by th e cur b or other
obstacles. If it is necessar y to driv e ove r curbs,
spee d hump s or similar elevations, tr y to do so
slowly and at an obtuse angle. Otherwise, th e
tires , particularly th e sidewalls, may be dam-
aged.
Regular checking of wheels and tires
G WARNIN G
Damaged tires can caus e tire inflation pres-
sur e loss . As a result , you could lose control of
your vehicle. Ther e is a ris k of accident.
Chec k th e tires regularly for sign s of damag e
and replace any damaged tires immediately.346
Operation
Wheels and tires

Sidewall The part of the tire between the tread and the
bead.
Weight of optional extras The combined weight of those optional extras
that weigh more than the replaced standard
parts and more than 2.3 kg (5 lbs). These
optional extras, such as high-performance
brakes, level control, a roof rack or a high-per-
formance battery, are not included in the curb
weight and the weight of the accessories.
TIN (Tire Identification Number) This is a unique identifier which can be used by
a tire manufacturer to identify tires, for example
for a product recall, and thus identify the pur-
chasers. The TIN is made up of the manufactur-
er's identity code, tire size, tire type code and
the manufacturing date.
Load bearing index The load bearing index (also load index) is a code
that contains the maximum load bearing capa-
city of a tire.
Traction Traction is the result of friction between the tires
and the road surface.
TWR (Tongue Weight Rating) The TWR specifies the maximum permissible
weight that the ball coupling of the trailer tow
hitch can support.
Treadwear indicators Narrow bars (tread wear bars) that are distrib-
uted over the tire tread. If the tire tread is level
with the bars, the wear limit of