2017 MERCEDES-BENZ GLS-Class SUV maintenance

Overview of climate control systems
General notes
Observe the settings recommended on the fol-
lowing pages. The windows could otherwise fog
up.
To prevent the windows from fogging up:
Rswitch off climate control only briefly
Rswitch on air-recirculation mode only briefly
Rswitch on the cooling with air dehumidifica-
tion function
Rswitch on the defrost windshield function
briefly, if required
Climate control regulates the temperature and
the humidity in the vehicle interior and filters
undesirable substances out of the air.
The residual heat function can only be activated
or deactivated with the ignition switched off
(
Ypage 133).
iVentilate the vehicle for a brief period during
warm weather, e.g. using the convenience
opening feature (
Ypage 87).
This will speed up the cooling process and the
desired interior temperature will be reached
more quickly. If you start the engine using your smartphone,
the last selected climate control setting is reac-
tivated (
Ypage 140).
iThe integrated filter filters out most parti-
cles of dust and soot and completely filters
out pollen. It also reduces gaseous pollutants
and odors. A clogged filter reduces the
amount of air supplied to the vehicle interior.
For this reason, you should always observe
the interval for replacing the filter, which is
specified in the Maintenance Booklet. As it
depends on environmental conditions, e.g.
heavy air pollution, the interval may be
shorter than stated in the Maintenance Book-
let.
iVehicles with AIR-BALANCE package: in
addition to ionization, the vehicle has an air
filter with anti-allergenic properties that con-
tribute to improved air filtration.
iIt is possible that under certain circumstan-
ces the residual heat function may be activa-
ted automatically an hour after the SmartKey
has been removed in order to dry the auto-
matic climate control. The vehicle is then ven-
tilated for 30 minutes.
Control panel for dual-zone automatic climate control
USA only
Front control panel
:Sets the temperature, left (Ypage 131)
;Defrosts the windshield (Ypage 132)
Overview of climate control systems123
Climate control

GWARNING
Limbs could be crushed or trapped if the
engine is started unintentionally during ser-
vice or maintenance work. There is a risk of
injury.
Always secure the engine against uninten-
tional starting before carrying out mainte-
nance or repair work.
Make sure that the engine cannot be started via
your smartphone before carrying out mainte-
nance or repairs. You can prevent an engine
start via your smartphone, for example, if you:
Rswitch on the hazard warning lamps
Rdo not lock the doors
Ropen the hood
Pulling away
General notes
GWARNING
If the engine speed is above the idling speed
and you engage transmission position Dor R,
the vehicle could pull away suddenly. There is
a risk of an accident.
When engaging transmission position Dor R,
always firmly depress the brake pedal and do not simultaneously accelerate.
Depress the accelerator carefully when pulling
away.
The vehicle locks centrally once you have pulled
away. The locking knobs in the doors drop down.
You can open the doors from the inside at any
time.
You can also deactivate the automatic locking
feature (
Ypage 239).
It is only possible to shift the transmission from
position Pto the desired position if you depress
the brake pedal. Only then is the parking lock
released. If you do not depress the brake pedal,
the DIRECT SELECT lever can still be moved but the parking lock remains engaged.
iUpshifts take place at higher engine speeds
after a cold start. This helps the catalytic con-
verter to reach its operating temperature
more quickly. Information on the automatic release of the
electric parking brake (
Ypage 161).
Pulling away with a trailer
To ensure that you do not roll backwards when
pulling away on an uphill slope, engage the elec-
tric parking brake.
XPress and hold handle
:.
The electric parking brake continues to brake
and prevent the vehicle from rolling back-
wards.
The red F(USA only) or !(Canada
only) indicator lamp in the instrument cluster remains on.
XDepress the accelerator pedal.
XAs soon as the vehicle/trailer combination isheld by the driving force of the engine, release
lever :.
the electric parking brake is released.
The red F(USA only) or !(Canada
only) indicator lamp in the instrument cluster goes out.
Hill start assist
Hill start assist helps you when pulling away for-
wards or in reverse on an uphill gradient. It holds
the vehicle for a short time after you have
removed your foot from the brake pedal. This
gives you enough time to move your foot from
the brake pedal to the accelerator pedal and to
depress it before the vehicle begins to roll.
GWARNING
After a short time, hill start assist will no lon-
ger brake your vehicle and it could roll away.
There is a risk of an accident and injury.
Therefore, quickly move your foot from the
brake pedal to the accelerator pedal. Never
Driving141
Driving and parking
Z

Problems with fuel and the fuel tank
ProblemPossible causes/consequences andMSolutions
Fuel is leaking from the
vehicle.GWARNING
The fuel line or the fuel tank is faulty.
Risk of explosion or fire.
XApply the electric parking brake.
XSwitch off the engine.
XRemove the SmartKey from the ignition lock.
or, on vehicles with KEYLESS‑GO:
XOpen the driver's door.
The on-board electronics now have status 0. This is the same as the
SmartKey having been removed.
XDo not restart the engine under any circumstances.
XConsult a qualified specialist workshop.
The engine does not
start.The fuel tank of a vehicle with a diesel engine has been run completely
dry.
XRefuel the vehicle with at least 5.3 US qt (5 liters) of diesel.
XTurn the ignition on for approximately ten seconds (Ypage 138).
XStart the engine continuously for up to ten seconds until it runs
smoothly.
If the engine does not start:
XTurn the ignition on again for approximately ten seconds
(Ypage 138).
XStart the engine again continuously for up to ten seconds until it
runs smoothly.
If the engine does not start after three attempts:
XConsult a qualified specialist workshop.
The fuel filler flap cannot
be opened.The fuel filler flap is not unlocked.
XUnlock the vehicle (Ypage 74).
The SmartKey battery is discharged or nearly discharged.
XUnlock the vehicle using the mechanical key (Ypage 76).
The fuel filler flap is unlocked, but the opening mechanism is jammed.
XConsult a qualified specialist workshop.
DEF (BlueTEC vehicles only)
General notes
To function properly, BlueTEC exhaust gas after-
treatment must be operated with the reducing
agent DEF. Adding DEF is one of the tasks per-
formed during maintenance. Under normal operating conditions, a tank of DEF lasts until
the next service due date.
When the supply of DEF is almost used up, the
Check Additive See Operator's Manualmessage is shown in the multifunction display.
If you drive the vehicle faster than 10 mph
(16 km/h), the
Check Additive See Opera‐
156Refueling
Driving and parking

tor's Manualmessage goes out after approx-
imately one minute.
When the DEF supply drops to a minimum, the
Remaining Starts: 16
message is shown in
the multifunction display.
If the Remaining Starts: 16
message
appears in the multifunction display, you can
start the engine another 16 times. If DEF is not
refilled, you will subsequently be unable to
start the engine.
XAdd at least 1 gal (3.8 l)of DEF.
XSwitch on the ignition for at least 60 seconds.
XStart the engine.
iHave the DEF tank refilled at a qualified spe-
cialist workshop.
Use the special DEF refill bottle when adding
DEF between maintenance intervals. You can
obtain further information from an authorized
Mercedes-Benz Center or, if necessary, contact
Roadside Assistance (
Ypage 27).
If the outside temperature is below 12 ‡(Ò11 †)
it may be difficult to top up. If DEF is frozen and
there is an active warning indicator, it may not
be possible to add DEF. Park the vehicle in a
warmer place, e.g. in a garage, until DEF has
become fluid again. It will then be possible to
add DEF again. Alternatively, have the DEF tank
refilled at a qualified specialist workshop.
Further information about BlueTEC exhaust gas aftertreatment and DEF is available at any
authorized Mercedes-Benz Center.
Important safety notes
DEF is a water-soluble fluid for the exhaust gas
aftertreatment of diesel engines. It is:
Rnot poisonous
Rcolorless and odorless
Rnot flammable
When you open the DEF container, small
amounts of ammonia vapor may be released.
Ammonia vapors have a pungent odor and are
particularly irritating to the skin, to mucous
membranes and to the eyes. You may experi-
ence a burning sensation in your eyes, nose and
throat. Coughing and watering of the eyes are
possible.
Do not inhale ammonia vapors. Fill the DEF tank
only in well-ventilated areas. DEF must not come into contact with your skin,
eyes or clothing and must not be swallowed.
Keep DEF away from children.
If you or other persons come into contact with
DEF, observe the following:
RRinse DEF from your skin immediately with
soap and water.
RIf DEF comes into contact with your eyes,
immediately rinse them thoroughly with clean
water. Seek medical assistance without
delay.
RIf DEF has been swallowed, rinse your mouth
out immediately. Drink plenty of water. Seek
medical assistance without delay.
RChange out of clothing contaminated with
DEF immediately.
!Only use DEF in accordance with
ISO 22241. Do not mix any additives with
DEF, and do not dilute DEF with water. This
may destroy the BlueTEC exhaust gas after-
treatment system.
!The vehicle must be parked on level ground
to fill the DEF tank. The DEF tank can only be
filled as intended with the vehicle parked on a
level surface. This avoids false level readings.
Filling the tank is not permitted if the vehicle
is not parked on a level surface. There is a
danger of overfil
ling, which could result in
damage to components of the BlueTEC
exhaust gas aftertreatment.
!Rinse surfaces that have come into contact
with DEF immediately with water or remove
DEF using a damp cloth and cold water. If the
DEF has already crystallized, use a sponge
and cold water to clean it. DEF residues crys-
tallize after time and contaminate the affec-
ted surfaces.
!DEF is not a fuel additive and must not be
added to the fuel tank. If DEF is added to the
fuel tank, this can lead to engine damage.
For further information on DEF, see
(
Ypage 381).
Refueling157
Driving and parking
Z

Emergency braking
The vehicle can also be braked during an emer-gency by using the electric parking brake.
XWhile driving, push handle :of the electric
parking brake.
The vehicle is braked for as long as the handle
of the electric parking brake is pressed. The
longer the electric parking brake handle is
depressed, the greater the braking force.
During braking:
Ra warning tone sounds
Rthe ReleasePark.Brakemessage appears
Rthe red F(USA only) or !(Canada
only) indicator lamp in the instrument cluster flashes
When the vehicle has been braked to a stand-
still, the electric parking brake is engaged.
Parking the vehicle for a long period
If you leave the vehicle parked for longer than
four weeks, the battery may be damaged by
exhaustive discharging.
If you leave the vehicle parked for longer than six
weeks, the vehicle may suffer damage as a
result of lack of use.
XVisit a qualified specialist workshop and seek
advice.
iYou can obtain information about trickle
chargers from a qualified specialist work-
shop.
Driving tips
General notes
Important safety notes
GWARNING
If you switch off the ignition while driving,
safety-relevant functions are only available
with limitations, or not at all. This could affect, for example, the power steering and the brake
boosting effect. You will require considerably
more effort to steer and brake. There is a risk
of an accident.
Do not switch off the ignition while driving.
GWARNING
If you operate mobile communication equip-
ment while driving, you will be distracted from traffic conditions. You could also lose control
of the vehicle. There is a risk of an accident.
Only operate this equipment when the vehicle
is stationary.
Observe the legal requirements for the country
in which you are driving. Some jurisdictions pro-
hibit the driver from using a mobile phone while
driving a vehicle.
If you make a call while driving, always use
hands-free mode. Only operate the telephone
when the traffic situation permits. If you are
unsure, pull over to a safe location and stop
before operating the telephone.
Bear in mind that at a speed of only 30 mph
(approximately 50 km/h), the vehicle covers a
distance of 44 ft (approximately 14 m)per sec-
ond.
Drive sensibly – save fuel
Observe the following tips to save fuel:
XThe tires should always be inflated to the rec-
ommended tire pressure.
XRemove unnecessary loads.
XRemove roof carriers when they are not nee-
ded.
XWarm up the engine at low engine speeds.
XAvoid frequent acceleration or braking.
XHave all maintenance work carried out as
indicated by the service intervals in the Main-
162Driving tips
Driving and parking

tenance Booklet or by the service interval dis-
play.
Fuel consumption also increases when driving in cold weather, in stop-start traffic and in hilly ter-
rain.
Drinking and driving
GWARNING
Drinking and driving and/or taking drugs and driving are very dangerous combinations.
Even a small amount of alcohol or drugs can
affect your reflexes, perceptions and judg-
ment.
The possibility of a serious or even fatal acci-
dent is greatly increased when you drink or
take drugs and drive.
Do not drink or take drugs and drive or allow
anyone to drive who has been drinking or tak-
ing drugs.
Emission control
GWARNING
Combustion engines emit poisonous exhaust
gases such as carbon monoxide. Inhaling
these exhaust gases leads to poisoning. There
is a risk of fatal injury. Therefore never leave
the engine running in enclosed spaces with-
out sufficient ventilation.
Certain engine systems are designed to keep
the level of poisonous components in exhaust
fumes within legal limits.
These systems only work at peak efficiency if
they are serviced exactly in accordance with the
manufacturer's specifications. Always have
work on the engine carried out at a qualified
specialist workshop. Mercedes-Benz recom-
mends that you use an authorized Mercedes-
Benz Center for this purpose. In particular, work
relevant to safety or on safety-related systems
must be carried out at a qualified specialist
workshop.
The engine settings must not be changed under any circumstances. Furthermore, all specific
service work must be carried out at regular
intervals and in accordance with the Mercedes-
Benz service requirements. Details can be found in the Maintenance Booklet.
ECO display
The ECO display shows you how economical
your driving style is. The ECO display assists you
in achieving the most economical driving style
for the selected settings and prevailing condi-
tions. Your driving style can significantly influ-
ence the vehicle's consumption.
:Acceleration
;Coasting
=Constant
?Additional range achieved
Range ?is shown under Bonus
fr.Startand
represents the additional range achieved since
the beginning of the journey as a result of an
adapted driving style.
If the fuel level has dropped into the reserve
range, the Reserve Fuel
message is shown in
the multifunction display instead of range ?.
The 8 warning lamp in the instrument cluster
also lights up (
Ypage 283).
Driving tips163
Driving an d parking
Z

parking brake is being tested on a brake dyna-
mometer (maximum 10 seconds).
Braking triggered automatically by ESP
®may
seriously damage the brake system.
All checks and maintenance work on the brake
system must be carried out at a qualified spe-
cialist workshop.
Have brake pads installed and brake fluid
replaced at a qualified specialist workshop.
If the brake system has only been subject to
moderate loads, you should test the functional-
ity of your brakes at regular intervals. To do so,
depress the brake pedal firmly when driving at a high speed. This improves the grip of the brake
pads.
You can find a description of Brake Assist (BAS)
on (
Ypage 64) or of BAS PLUS on (Ypage 69).
Mercedes-Benz recommends that you only have
brake pads/linings installed on your vehicle
which have been approved for Mercedes-Benz
vehicles or which correspond to an equivalent
quality standard. Brake pads/linings which have
not been approved for Mercedes-Benz vehicles
or which are not of an equivalent quality could
affect your vehicle's operating safety.
Mercedes-Benz recommends that you only use
brake fluid that has been specially approved for
your vehicle by Mercedes-Benz, or which corre-
sponds to an equivalent quality standard. Brake
fluid which has not been approved for
Mercedes-Benz vehicles or which is not of an
equivalent quality could affect your vehicle's
operating safety.
High-performance brake system
(Mercedes-AMG vehicles)
The high-performance brake system is designed
for heavy loads. This may lead to noise when
braking. This will depend on:
RSpeed
RBraking force
REnvironmental conditions, such as tempera-
ture and humidity
The wear of individual components of the brake
system, such as the brake pads/linings or brake
discs, depends on the individual driving style
and operating conditions.
For this reason, it is impossible to state a mile-
age that will be valid under all circumstances. An
aggressive driving style will lead to high wear. You can obtain further information about this
from your authorized Mercedes-Benz Center.
New and replaced brake pads and discs only
reach their optimum braking effect after several
hundred kilometers of driving. Compensate for
this by applying greater force to the brake pedal.
Keep this in mind, and adapt your driving and
braking accordingly during this break-in period.
Excessive heavy braking results in correspond-
ingly high brake wear. Observe the #brake
wear warning lamp in the instrument cluster and
note any brake status messages in the multi-
function display. Especially for high perform-
ance driving, it is important to maintain and have
the brake system checked regularly.
Driving on wet roads
Hydroplaning
If water has accumulated to a certain depth on
the road surface, there is a danger of hydro-
planing occurring, even if:
Ryou drive at low speeds.
Rthe tires have adequate tread depth.
For this reason, in the event of heavy rain or in
conditions in which hydroplaning may occur,
you must drive in the following manner:
Rlower your speed.
Ravoid ruts.
Ravoid sudden steering movements.
Rbrake carefully.
Driving on flooded roads
!Do not drive through flooded areas. Check
the depth of any water before driving through it. Drive slowly through standing water. Oth-
erwise, water may enter the vehicle interior or
the engine compartment. This can damage
the electronic components in the engine or
the automatic transmission. Water can also
be drawn in by the engine's air suction nozzles
and this can cause engine damage.
iVehicles with the AIRMATIC package:
select the raised vehicle level before driving
through a body of water.
166Driving tips
Driving and parking

Engine compartment
Hood
Important safety notes
GWARNING
If the hood is unlatched, it may open up when the vehicle is in motion and block your view.
There is a risk of an accident.
Never unlatch the hood while driving. Before
every trip, ensure that the hood is locked.
GWARNING
When opening and closing the hood, it may
suddenly fall into the closed position. There is a risk of injury to persons within range of
movement of the hood.
Open and close the hood only when no one is
within its range of movement.
GWARNING
Opening the hood when the engine is over-
heated or when there is a fire in the engine
compartment could expose you to hot gases
or other service products. There is a risk of
injury.
Let an overheated engine cool down before
opening the hood. If there is a fire in the
engine compartment, keep the hood closed
and contact the fire department.
GWARNING
The engine compartment contains moving
components. Certain components, such as
the radiator fan, may continue to run or start
again suddenly when the ignition is off. There is a risk of injury.
If you need to do any work inside the engine
compartment:
Rswitch off the ignition
Rnever reach into the area where there is a
risk of danger from moving components,
such as the fan rotation area
Rremove jewelry and watches
Rkeep items of clothing and hair, for exam-
ple, away from moving parts
GWARNING
The ignition system and the fuel injection sys-
tem work under high voltage. If you touch
components which are under voltage, you
could get an electric shock. There is a risk of
injury.
Never touch components of the ignition sys-
tem or fuel injection system when the ignition
is switched on.
Opening the hood
GWARNING
Certain components in the engine compart-
ment, such as the engine, radiator and parts
of the exhaust system, can become very hot.
Working in the engine compartment poses a
risk of injury.
Where possible, let the engine cool down and touch only the components described in the
following.
GWARNING
When the hood is open and the windshield
wipers are set in motion, you can be injured by
the wiper linkage. There is a risk of injury.
Always switch off the windshield wipers and
the ignition before opening the hood.
!Make sure that the windshield wipers are
not folded away from the windshield. You
could otherwise damage the windshield wip-
ers or the hood.
Engine compartment319
Maintenance and care
Z