warning lights MERCEDES-BENZ GLS 2017 User Guide

Problem
Possible causes/consequences and P Solutions
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. X
Make sure the conditions for a correct classification of the person
on the front-passenger seat are met ( Y
page 49).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 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: R
unoccupied R
occupied with 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 possible
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 accord-
ingly. X
Make sure that no objects are applying additional weight onto the
seat. X
If 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. X
Have OCS checked as soon as possible at an authorized Mercedes-
Benz Center.
Deployment of Emergency Tensioning
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 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
and to have any malfunctioning air bagsOccupant safety 53
Safety Z

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.
G WARNING
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 a small amount of powder may also be
released. The u 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: 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 frontal or
rear 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 42) R
the belt tongue is engaged in the buckle on
the respective front-passenger 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: R
Front air bags and driver's knee bag R
Window 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 the
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 ( Y
page 42).
Your vehicle has two-stage front air bags. During
the first deployment stage, the front air bag is
filled with propellant gas to reduce the risk of
injuries. The front air bag is fully deployed with
the maximum amount of propellant gas if a sec-
ond deployment threshold is reached within a
few milliseconds.
The activation threshold of the Emergency Ten-
sioning Devices and the air bag are determined
by evalua ting the rate of vehicle deceleration or
a cceleration 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: R
the distribution of forces during the collision R
the collision angle R
the deformation characteristics of the vehicle 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 deci-54
Occupant safety
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

SmartKey battery
Important safety notes
G WARNING
Batteries contain toxic and corrosive substan-
ces. If batteries are swallowed, it can result in
severe health problems. There is a risk of fatal
injury.
Keep batteries out of the reach of children. If
a battery is swallowed, seek medical attention
immediately.
H Environmental note
Batteries contain dangerous
substances. It is against the
law to dispose of them with
the household rubbish. They
must be collected separately
and recycled to protect the
environment.
Dispose of batteries in an
environmentally friendly
manner. Take discharged
batteries to a qualified spe-
cialist workshop or a special
collection point for used bat-
teries.
The SmartKey batteries contain perchlorate
material, 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 .
Mercedes-Benz recommends that you have the
batteries replaced at a qualified specialist work-
shop. Checking the battery X
Press the 7 or 6 button.
The battery is working properly if battery
check lamp C lights up briefly.
The battery is discharged if battery check
lamp C does not light up briefly. X
Change the battery ( Y
page 77).
If the SmartKey battery is checked within the
signal reception range of the vehicle, pressing
the 7 or 6 button: R
locks or R
unlocks the vehicle
i You can get a battery at any qualified spe-
cialist workshop.
Replacing the battery You require a CR 2025 3 V cell battery. X
Take the mechanical key out of the SmartKey
( Y
page 76).
X
Press mechanical key D into the SmartKey
opening in the direction of the arrow until bat-
tery compartment cover C opens. Do not
hold battery compartment cover C closed
while doing so. X
Remove battery compartment cover C .SmartKey 77
Opening and closing Z

G WARNING
The exterior mirror on the front-passenger
side reduces the size of the image. Visible
objects are actually closer than they appear.
This means that you could misjudge the dis-
tance from road users traveling behind, e.g.
when changing lane. There is a risk of an acci-
dent.
For this reason, always make sure of the
actual distance from the road users traveling
behind by glancing over your shoulder.
X
Turn the SmartKey to position 1 or 2 in the
ignition lock ( Y
page 138).X
Exterior mirror on the driver's side: press but-
ton C .
Exterior mirror on the front-passenger side:
press button D .
The indicator lamp in the corresponding but-
ton lights up in red.
The indicator lamp goes out again after some
time. You can adjust the selected exterior
mirror using button

The blue W indicator lamp in the instru-
ment cluster lights up when the high-beam
headlamps are switched on. X
To switch off the high-beam head-
lamps: move the combination switch back to
its normal position.
The blue W indicator lamp in the instru-
ment cluster goes out.
Vehicles with Adaptive Highbeam Assist: if
Adaptive Highbeam Assist is activated, it auto-
matically controls activation and deactivation of
the high-beam headlamps ( Y
page 115).
Hazard warning lamps
X
To switch on the hazard warning
lamps: press button C .
All turn signals flash. If you now switch on a
turn signal using the combination switch, only
the turn signal lamp on the corresponding
side of the vehicle will flash. X
To switch off the hazard warning lamps:
press button C .
The hazard warning lamps automatically switch
on if: R
an air bag is deployed or R
the vehicle decelerates rapidly from a speed
of above 45 mph (70 km/h) and comes to a
standstill
The hazard warning lamps switch off automati-
cally if the vehicle reaches a speed of above
6 mph (10 km/h) again after a full brake appli-
cation.
i The hazard warning lamps still operate if the
ignition is switched off. Intelligent Light System
General notes The Intelligent Light System is a system that
adjusts the headlamps automatically to suit the
prevailing driving and weather conditions. It
offers advanced functions for improved illumi-
nation of the road surface, e.g. depending on the
vehicle speed or weather conditions. The sys-
tem includes the active light function, cornering
light function, highway mode and extended
range fog lamps. The system is only active when
it is dark.
You can activate or deactivate the "Intelligent
Light System" using the on-board computer
( Y
page 239).
Active light function The active light function is a system that moves
the headlamps according to the steering move-
ments of the front wheels. In this way, relevant
areas remain illuminated while driving. This
allows you to identify pedestrians, cyclists and
animals.
Active: when the lights are switched on.
Cornering light function The cornering light function improves the illu-
mination of the road over a wide angle in the
direction you are turning, enabling better visi-
bility in tight bends, for example. It can only be
activated when the low-beam headlamps are
switched on.
Active: R
if you are driving at speeds below 25 mph
(40 km/ h) and switch on the turn signal or
turn the steering wheel R
if you are driving at speeds between 25 mph
(40 km/h) and 45 mph (70 km/h) and turn
the steering wheel
The cornering lamp may remain lit for a short
time, but is automatically switched off after no
more than three minutes.
Highway mode
Highway mode increases the range of the beam.
Active: if you are driving at a speed above
110 km/h and do not make any large steering
movements for at least 1,000 m or if you are
driving at a speed above 130 km/h.114
Exterior lighting
Lights and windshield wipers

Not active: if you are driving at speeds below
80 km/h following activation.
Extended range fog lamps The extended range fog lamps reduce the glare
experienced by the driver and improve the illu-
mination of the edge of the road.
Active: if you are driving at speeds below
40 mph (70 km/h) and you switch on the rear
fog lamp.
Not active: if, following activation, you are driv-
ing at speeds above 60 mph (100 km/h) or if you
switch off the rear fog lamp
Off-road lights The off-road lights facilitate the early recogni-
tion of objects/obstacles when driving off-road
thanks to a symmetrical, wider and brighter dis-
tribution of light from the low-beam headlamps.
Active: when driving at speeds no faster than
30 mph (50 km/h) and the off-road program
selector wheel is in position 1 or 2.
Not active: when driving at speeds above
30 mph (50 km/h).
When the off-road lights are switched on, the
cornering light function is permanently activa-
ted, the active light function is deactivated and
the headlamp range control is set to static
mode.
Cornering light function The cornering light function improves the illu-
mination of the road over a wide angle in the
direction you are turning, enabling better visi-
bility in tight bends, for example. It can only be
activated when the low-beam headlamps are
switched on.
Active: R
if you are driving at speeds below 25 mph
(40 km/h) and switch on the turn signal or
turn the steering wheel R
if you are driving at speeds between 25 mph
(40 km/h) and 45 mph (70 km/h) and turn
the steering wheel
The cornering lamp may remain lit for a short
time, but is automatically switched off after no
more than three minutes. Adaptive Highbeam Assist
General notes You can use this function to set the headlamps
to change between low beam and high beam
automatically. The system recognizes vehicles
with their lights on, either approaching from the
opposite direction or traveling in front of your
vehicle, and consequently switches the head-
lamps from high beam to low beam.
The system automatically adapts the low-beam
headlamp range depending on the distance to
the other vehicle. Once the system no longer
detects any other vehicles, it reactivates the
high-beam headlamps.
The system's optical sensor is located behind
the windshield near the overhead control panel.
Important safety notes
G WARNING
Adaptive Highbeam Assist does not recognize
road users: R
who have no lights, e.g. pedestrians R
who have poor lighting, e.g. cyclists R
whose lighting is blocked, e.g. by a barrier
On very rare occasions, Adaptive Highbeam
Assist may fail to recognize other road users
that have lights, or may recognize them too
late. In this, or in similar situations, the auto-
matic high-beam headlamps will not be deac-
tivated or will be activated regardless. There is
a risk of an accident.
Always carefully observe the traffic conditions
and switch off the high-beam headlamps in
good time.
Adaptive Highbeam Assist cannot take into
account road, weather or traffic conditions.
Adaptive Highbeam Assist is only an aid. You are
responsible for adjusting the vehicle's lighting
to the prevailing light, visibility and traffic con-
ditions.
In particular, the detection of obstacles can be
impaired if: R
poor visibility, e.g. due to fog, heavy rain or
snow R
dirt on the sensors or the sensors are
obscuredExterior lighting 115
Lights and windshield wiper s Z

been switched off. The heating time depends on
the set interior temperature.
Switching on/off X
To activate: press the K or V button.
The indicator lamp in the K or V button
lights up.
i The blower will run at a low speed regardless
of the airflow setting.
i If you activate the residual heat function at
high temperatures, only the ventilation will be
activated. The blower runs at medium speed. X
To deactivate: press the K or V but-
ton.
The indicator lamp in the K or V button
goes out.
Residual heat is deactivated automatically: R
after approximately 30 minutes R
when the ignition is switched on R
if the battery voltage drops
Ionization Ionization is used to purify the air in the vehicle
interior and attain an improved interior climate.
The ionization of the interior air is odorless and
cannot be perceived directly in the vehicle inte-
rior.
You can switch ionization on and off via the mul-
timedia system (see the separate operating
instructions).
Ionization can only be operated when the auto-
matic climate control is switched on. The side air
vent on the driver's side must be open.
Setting the air vents
Important safety notes
G WARNING
Very hot or very cold air can flow from the air
vents. This could result in burns or frostbite in
the immediate vicinity of the air vents. There
is a risk of injury.
Make sure that all vehicle occupants always
maintain a sufficient distance to the air out- lets. If necessary, redirect the airflow to
another area of the vehicle interior.
In order to ensure the direct flow of fresh air
through the air vents into the vehicle interior,
please observe the following notes: R
keep the air inlet grille on the hood and in the
engine compartment on the front-passenger
side free of blockages, such as ice, snow or
leaves. R
never cover the air vents or air intake grilles in
the vehicle interior.
i For virtually draft-free ventilation, adjust the
sliders of the air vents to the center position.
Setting the center air vents
C
Center air vent, left D
Center air vent, right

ignite if in contact with the exhaust system or
parts of the engine that heat up. There is a risk
of fire.
Carry out regular checks to make sure that
there are no flammable foreign materials in
the engine compartment or in the exhaust
system.
General notes Vehicles with a gasoline engine: the catalytic
converter is preheated for up to 30 seconds
after a cold start. The sound of the engine may
change during this time.
Automatic transmission X
Shift the transmission to position P
( Y
page 146).
The transmission position display in the mul-
tifunction display shows P ( Y
page 148).
i You can start the engine in transmission
position P and N .
Starting procedure with the SmartKey X
To start a diesel engine : turn the SmartKey
to position 2 in the ignition lock ( Y
page 138).
The \( preglow indicator lamp in the instru-
ment cluster lights up. X
Turn the SmartKey to position 3 in the ignition
lock and release it as soon as the engine is
running ( Y
page 138).
i Vehicles with a diesel engine: you can
start the engine without preglow if the engine
is warm.
Using KEYLESS-GO to start the engine The Start/Stop button can be used to start the
vehicle without inserting the SmartKey into the
ignition lock. The Start/Stop button must be
inserted in the ignition lock and the SmartKey
must be in the vehicle. This mode for starting the
engine operates independently of the ECO
start/stop automatic engine start function. X
Depress the brake pedal and keep it
depressed. X
Press the Start/Stop button once
( Y
page 138).
Vehicles with a gasoline engine: the engine
starts.
Vehicles with a diesel engine: preglow is
activated and the engine starts.
Starting procedure via smartphone Observe the important safety notes on starting
the engine ( Y
page 139).
You can also start your engine via your smart-
phone from outside the vehicle. In this case, the
previously selected climate control setting is
activated. In this way you can cool or heat the
interior of the vehicle before starting the jour-
ney.
Only start the engine via your smartphone if it is
safe to start and run the engine where your vehi-
cle is parked.
Observe the legal stipulations in the area where
your vehicle is parked. Engine start via smart-
phone may be limited to certain countries or
regions.
You can execute a maximum of two consecutive
starting attempts via your smartphone. If you
insert the SmartKey into the ignition lock, you
can carry out two more starting attempts.
Once you have started the engine, you can
switch the engine off via your smartphone at any
time.
You can only start the engine via your smart-
phone if: R
the SmartKey is in the ignition lock R
park position P is selected R
the accelerator pedal is not depressed R
the anti-theft alarm system is not activated R
the panic alarm is not activated R
the hazard warning lamps are switched off R
the hood is closed. R
the doors are closed and locked R
the windows and sliding sunroof are closed
Also make sure that: R
the fuel tank is sufficiently filled R
the starter battery is sufficiently charged140
Driving
Driving and parking

This helps you to avoid overheating the
brakes and wearing them out excessively.
When you take advantage of engine braking, a
drive wheel may not turn for some time, e.g.
on a slippery road surface. This could cause
damage to the drive train. This type of damage
is not covered by the Mercedes-Benz war-
ranty.
Do not depress the brake pedal continuously
while the vehicle is in motion, e.g. causing the
brakes to rub by constantly applying light pres-
sure to the pedal. This results in excessive and
premature wear to the brake pads.
Use the left-hand steering wheel paddle shifter
to shift into a lower gear in good time on long
and steep downhill gradients. This is especially
important if the vehicle is laden.
This also applies if you have activated cruise
control, the speed limiter 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.
Heavy and light loads
G WARNING
If you rest your foot on the brake pedal while
driving, the braking system can overheat. This
increases the stopping distance and can even
cause the braking system to fail. There is a
risk of an accident.
Never use the brake pedal as a footrest. Never
depress the brake pedal and the accelerator
pedal at the same time.
! Depressing the brake pedal constantly
results in excessive and premature wear to
the brake pads.
If the brakes have been subjected to a heavy
load, do not stop the vehicle immediately. Drive
on for a short while. This allows the airflow to
cool the brakes more quickly.
Wet roads
If you have driven for a long time in heavy rain
without braking, there may be a delayed reac-
tion from the brakes when braking for the first time. This may also occur after the vehicle has
been washed or driven through deep water.
You then have to depress the brake pedal more
firmly. Maintain a greater distance from the
vehicle in front.
After driving on a wet road or having the vehicle
washed, brake firmly while paying attention to
the traffic conditions. This will warm up the
brake discs, thereby drying them more quickly
and protecting them against corrosion.
Limited braking performance on salt-
treated roads If you drive on salted roads, a layer of salt resi-
due may form on the brake discs and brake
pads. This can result in a significantly longer
braking distance. R
Brake occasionally to remove any possible
salt residue. Make sure that you do not
endanger other road users when doing so. R
Carefully depress the brake pedal and the
beginning and end of a journey. R
Maintain a greater distance to the vehicle
ahead.
Servicing the brakes
! The brake fluid level may be too low, if: R
if the red brake warning lamp lights up in
the instrument cluster and R
you hear a warning tone while the engine is
running
Observe additional warning messages in the
multifunction display.
The brake fluid level may be too low due to
brake pad wear or leaking brake lines.
Have the brake system checked immediately.
Consult a qualified specialist workshop to
arrange this.
! A function or performance test should only
be carried out on a 2-axle dynamometer. If
you wish to operate the vehicle on such a
dynamometer, please consult a qualified spe-
cialist workshop in advance. You could oth-
erwise damage the drive train or the brake
system.
! Because ESP ®
is an automatic system, the
engine and ignition must be switched off
(SmartKey in position 0 or 1 or Start/Stop
button in position 0 or 1 ) when the electricDriving tips 165
Driving and parking Z