2019 MERCEDES-BENZ GLS SUV warning

Replacing the 12 V battery
Observe the notes on the 12 V battery.
Mercedes-Benz recommends that you have the
12 V battery replaced at a qualified specialist
workshop, e.g. at an authorized Mercedes-Benz
Center.
If you want to replace the battery yourself,
observe the following notes:
R Always replace a defective battery with a bat-
tery which meets the specific requirements of
the vehicle.
The vehicle is equipped with an AGM (Absorb-
ent Glass Mat) technology battery. Full vehi-
cle functionality is only guaranteed with an AGM battery. For safety reasons, Mercedes-
Benz recommends that you only use batteries
which have been tested and approved for your
vehicle by Mercedes-Benz.
R Use detachable parts such as breather hoses,
angled connecting pieces or terminal covers
from the battery which is to be replaced.
R Make sure that the vent hose is always con-
nected to the original opening on the battery
side.
Install any existing or supplied stop plugs.
Otherwise, gases or battery acid could
escape.
R Make sure that the detachable parts are con-
nected again in the same way. Jump-starting
For the jump-starting procedure, use only the jump-starting connection point in the engine com-
partment, consisting of a positive terminal and a ground point. G
WARNING
Battery acid is caustic. There is a risk of injury.
Avoid contact with skin, eyes or clothing. Do not inhale any battery gases. Do not lean over the
battery. Keep children away from batteries. Wash away battery acid immediately with plenty of
clean water and seek medical attention. G
WARNING
During charging and jump-starting, explosive gases can escape from the battery. There is a risk of an explosion.
Particularly avoid fire, open flames, creating sparks and smoking. Ensure there is sufficient ven-
tilation while charging and jump-starting. Do not lean over a battery. G
WARNING
During the charging process, a battery produces hydrogen gas. If a short circuit occurs or sparks
are created, the hydrogen gas can ignite. There is a risk of an explosion.
R Make sure that the positive terminal of a connected battery does not come into contact with
vehicle parts.
R Never place metal objects or tools on a battery.
R It is important that you observe the described order of the battery terminals when connecting
and disconnecting a battery.
R When jump-starting, make sure that the battery poles with identical polarity are connected.
R It is particularly important to observe the described order when connecting and disconnecting
the jumper cables.
R Never connect or disconnect the battery terminals while the engine is running. Jump-starting
343Breakdown assistance Z

G
WARNING
A discharged battery can freeze at temperatures below freezing point. When jump-starting the
vehicle or charging the battery, gases can escape from the battery. There is a risk of an explosion.
Allow the frozen battery to thaw out before charging it or jump-starting.
! Vehicles with a gasoline engine:
avoid repeated and lengthy starting attempts. Otherwise, the
catalytic converter could be damaged by non-combusted fuel.
If the indicator/warning lamps do not light up at low temperatures, it is very likely that the dis-
charged battery has frozen. In this case you may neither jump-start the vehicle nor charge the
battery. The service life of a thawed-out battery may be shorter. The starting characteristics can be
impaired, particularly at low temperatures. Have the thawed-out battery checked at a qualified
specialist workshop.
Do not start the vehicle using a rapid charging device. If your vehicle's battery is discharged, the
engine can be jump-started from another vehicle or from a donor battery using jumper cables.
Observe the following points:
R The battery is not accessible in all vehicles. If the other vehicle's battery is not accessible, jump-
start the vehicle using a donor battery or a jump-starting device.
R Vehicles with a gasoline engine: only jump-start the vehicle when the engine and exhaust
system are cold.
R Do not start the engine if the battery is frozen. Let the battery thaw first.
R Only jump-start from batteries with a 12 V voltage rating.
R Only use jumper cables which have a sufficient cross-section and insulated terminal clamps.
R If the battery is fully discharged, leave the battery that is being used to jump-start connected for
a few minutes before attempting to start. This charges the battery slightly.
R Make sure that the two vehicles do not touch.
Make sure that:
R The jumper cables are not damaged.
R Bare parts of the terminal clamp do not come into contact with other metal parts while the jumper
cables are connected to the battery.
R The jumper cables cannot come into contact with parts that can move when the engine is running,
such as the V-belt pulley or the fan.
X Secure the vehicle by applying the electric parking brake.
X Shift the transmission to position 005D.
X Make sure that the ignition is switched off. All indicator lamps in the instrument cluster must be
off. When using the SmartKey, turn the SmartKey to position 0092in the ignition lock and remove it
(Y page 140).
X Switch off all electrical consumers, e.g. rear window defroster, lighting, etc.
X Open the hood.
i Right-hand-drive vehicle:
the jump-starting connection points may be located on the other
side of the vehicle. 344
Jump-startingBreakdown assistance

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 383).
! When Active Brake Assist, Active Distance
Assist 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 Make sure that the tow rope is not longer
than legally permitted. Mark the tow rope in
the middle, e.g. with a white cloth
(11.8 x 11.8 in). This will make other road
users aware that a vehicle is being towed.
R Only secure the tow cable to the towing
eyes or, if available, to the trailer tow hitch.
R Observe the brake lamps of the towing
vehicle while driving. Always maintain a dis-
tance a distance 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 away vehicles with KEYLESS-
GO, use the key instead of the Start/Stop
button. The automatic transmission may oth-
erwise shift to position 005Dwhen you open the
driver's or front-passenger door, which could damage 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.
When towing, the differential locks must not
be switched on. The transmission may other- wise be damaged.
! You may tow the vehicle for a maximum dis-
tance of 30 miles (50 kilometers). A towing 346
Towing and tow-startingBreakdown assistance

In order to ensure that the automatic transmis-
sion stays in position 005Cwhen towing away the
vehicle, you must observe the following points:
X Make sure that the vehicle is stationary.
X Turn the SmartKey to position 0048in the igni-
tion lock.
X Depress and hold the brake pedal.
X Shift the automatic transmission to position
005C.
X Leave the SmartKey in position 0048in the igni-
tion lock.
X Release the brake pedal.
X Release the electric parking brake.
X Switch on the hazard warning lamps
(Y page 117).
In order to signal a change of direction when
towing the vehicle with the hazard warning
lamps switched on, use the combination switch as usual. In this case, only the indicator lamps
for the direction of travel flash. After resetting
the combination switch, the hazard warning
lamp starts flashing again. Transporting the vehicle
4MATIC vehicles/vehicles with auto-
matic transmission !
When the vehicle is loaded for transport, the
front and rear axles must be stationary and on
the same transportation vehicle. Positioning
over the connection point of the transport
vehicle is not permitted. The drive train may
otherwise be damaged. All vehicles !
You may only secure the vehicle by the
wheels, not by parts of the vehicle such as
axle or steering components. Otherwise, the
vehicle could be damaged.
The towing eye can be used to pull the vehicle
onto a trailer or transporter for transporting pur-
poses.
X Turn the SmartKey to position 0048in the igni-
tion lock.
X Shift the automatic transmission to position
005C.
As soon as the vehicle has been loaded:
X Prevent the vehicle from rolling away by
applying the electric parking brake.
X Shift the automatic transmission to position
005D.
X Turn the SmartKey to position 0092in the igni-
tion lock and remove it.
X Secure the vehicle.
Securing the vehicle !
After loading, the vehicle must be secured at
all four wheels. Otherwise, the vehicle could
be damaged.
A minimum distance of 8 in (20 cm) up and
4 in (10 cm) down must be maintained to the transport platform.
X Secure all four wheels after loading the vehi-
cle.
Vehicles with ADS PLUS (Adaptive
Damping System PLUS) Important safety notes
G
WARNING
The weaker damping forces of the vehicle to
be transported can cause the vehicle/trailer
combination to swing.
As a result, when transporting vehicles with
Adaptive Damping System PLUS, the vehicle/ trailer combination may start to skid. Conse-
quently, you could lose control of the vehicle.
There is a risk of accident and injury. 348
Towing and tow-startingBreakdown assistance

When transporting, make sure that:
R the vehicle is has been loaded onto the
transporter correctly
R the vehicle is secured at all four wheels with
suitable tensioning straps
R you do not exceed the maximum permissi-
ble speed of 35 mph (60 km/h)
Securing the vehicle ! After loading, the vehicle must be secured at
all four wheels. Otherwise, the vehicle could
be damaged.
A minimum distance of 8 in (20 cm) up and
4 in (10 cm) down must be maintained to the
transport platform.
X Secure all four wheels after loading the vehi-
cle. Information on 4MATIC vehicles
! Vehicles with 4MATIC must not be towed
with either the front or the rear axle raised, as
doing so will damage the transmission.
Vehicles with 4MATIC may either be towed away with both axles on the ground or be loaded up
and transported.
If the vehicle's transmission, front, or rear axle is
damaged, have the vehicle transported on a
truck or trailer.
In the event of damage to the electrical sys-
tem: if the battery is defective, the automatic
transmission will be locked in position 005D. To
shift the automatic transmission to position 005C,
you must provide power to the vehicle's on-
board electrical system in the same way as
when jump-starting (Y page 343).
Have the vehicle transported on a transporter or
trailer. Tow-starting (emergency engine
starting)
! Vehicles with automatic transmission must
not be tow-started. You could otherwise dam- age the automatic transmission.
You can find information on "Jump-starting"
under (Y page 343). Fuses
Important safety notes
G
WARNING
If you manipulate or bridge a faulty fuse or if
you replace it with a fuse with a higher amper- age, the electric cables could be overloaded.
This could result in a fire. There is a risk of an
accident and injury.
Always replace faulty fuses with the specified
new fuses having the correct amperage.
! For the fuse boxes in the engine compart-
ment and under the rear bench seat, only use fuses with the suffix "S". Otherwise, compo-
nents or systems could be damaged.
! Make sure that no moisture can enter the
fuse box when the cover is open.
! When closing the cover, make sure that it is
lying correctly on the fuse box. Moisture seep-
ing in or dirt could otherwise impair the oper- ation of the fuses.
The fuses in your vehicle serve to close down
faulty circuits. If a fuse blows, all the compo-
nents on the circuit and their functions stop
operating.
Blown fuses must be replaced with fuses of the
same rating, which you can recognize by the
color and value. The fuse ratings are listed in the fuse allocation chart.
The fuse allocation chart is located in the fuse
box under the rear bench seat (Y page 350).
If a newly inserted fuse also blows, have the
cause traced and rectified at a qualified special- ist workshop, e.g. an authorized Mercedes-Benz
Center. Before changing a fuse
Observe the important safety notes
(Y page 349)
X Switch off the engine.
X Switch off all electrical consumers. Fuses
349Breakdown assistance Z

X
Remove the SmartKey from the ignition lock.
Or, on vehicles with KEYLESS-GO start function
or KEYLESS‑GO:
X Open the driver's door.
The vehicle electronics are now in key posi-
tion 0092. This is the same as the SmartKey
having been removed.
The driver’s door can be closed again.
X Secure the vehicle against rolling away
(Y page 158).
All indicator lamps in the instrument cluster
must be off.
The fuses are located in various fuse boxes:
R Fuse box on the front-passenger side of the
dashboard
R Fuse box in the engine compartment on the
right-hand side of the vehicle, when viewed in
the direction of travel
R Fuse box under the rear bench seat Dashboard fuse box
! Do not use a pointed object such as a screw-
driver to open the cover in the dashboard. You
could damage the dashboard or the cover.
Mercedes-Benz recommends that you have this work performed at a qualified specialist work-
shop, e.g. at an authorized Mercedes-Benz Cen-
ter. X
Open the front-passenger door.
X To open: pull cover 0043outwards in the direc-
tion of the arrow and remove it.
X To close: clip in cover 0043on the front of the
dashboard.
X Fold cover 0043inwards until it engages. Fuse box in the engine compartment
G
WARNING
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. X
Open the hood (Y page 321).
X Use a dry cloth to remove any moisture from
the fuse box.
X To open: open clamps 0044.
X Fold up cover 0043in the direction of the arrow
and remove it.
X To close: check whether the seal is seated
correctly in cover 0043.
X Insert cover 0043at the side of the fuse box into
the retainers.
X Fold down cover 0043and close clamps 0044.
X Close the hood. Fuse box under the rear bench seat350
FusesBreakdown assistance

Important safety notes
G
WARNING
If you install wheels and tires with incorrect
dimensions, the service brake or wheel sus-
pension components may be damaged. There is a risk of an accident.
Always replace wheels and tires with ones
that comply with the specifications of the
original part.
When replacing wheels, pay attention to the:
R Designation
R Model
When replacing tires, pay attention to the:
R Designation
R Manufacturer
R Model G
WARNING
A flat tire will severely affect the driving char- acteristics as well as the steering and braking
of the vehicle. There is a risk of an accident.
Tires without run-flat characteristics:
R Do not drive on with a flat tire.
R Change the flat tire immediately with an
emergency spare wheel or spare wheel.
Alternatively, consult a qualified specialist
workshop.
Tires with run-flat characteristics:
R Observe the information and warning notes
on MOExtended tires (run-flat tires).
Accessories that are not approved for your vehi-
cle by Mercedes-Benz or are not being used cor- rectly can impair the operating safety.
Before purchasing and using non-approved
accessories, visit a qualified specialist work-
shop and inquire about:
R suitability
R legal stipulations
R factory recommendations
Further information regarding wheels and tires
can be found under "Wheel/tire combinations"
(Y page 377). You can ask for information regarding permitted
wheel/tire combinations at an authorized
Mercedes-Benz Center.
Tire pressure information can be found:
R on the Tire and Loading Information placard
on the B-pillar on the driver's side
R in the tire pressure table in the fuel filler flap
R in the "Tire pressure" section Operation
Information on driving
Check the tire pressure when the vehicle is
heavily laden and adjust prior to a trip.
While driving, pay attention to vibrations, noises and unusual handling characteristics, e.g. pull-
ing to one side. This may indicate that the
wheels or tires are damaged. If you suspect that
a tire is defective, reduce your speed immedi-
ately. Stop the vehicle as soon as possible to
check the wheels and tires for damage. Hidden tire damage could also be causing the unusual
handling characteristics. If you find no signs of
damage, have the tires and wheels checked at a
qualified specialist workshop.
When parking your vehicle, make sure that the
tires do not get deformed by the curb or other
obstacles. If it is necessary to drive over curbs,
speed humps or similar elevations, try to do so
slowly and at an obtuse angle. Otherwise, the
tires, particularly the sidewalls, may be dam-
aged. Regular checking of wheels and tires
G
WARNING
Damaged tires can cause tire inflation pres-
sure loss. As a result, you could lose control of your vehicle. There is a risk of accident.
Check the tires regularly for signs of damage
and replace any damaged tires immediately.
Check wheels and tires for damage at least once a month. Check wheels and tires after driving
off-road or on rough roads. Damaged wheels
can cause a loss of tire pressure.
Pay particular attention to damage such as:
R cuts in the tires
R punctures in the tires 352
OperationWheels and ti
res

R
tears in the tires
R bulges on tires
R deformation or severe corrosion on wheels
Regularly check the tire tread depth and the
condition of the tread across the whole width of
all tires (Y page 353). If necessary, turn the
front wheels to full lock in order to inspect the
inner side of the tire surface.
All wheels must have a valve cap to protect the
valve against dirt and moisture. Do not mount
anything onto the valve other than the standard valve cap or other valve caps approved by
Mercedes-Benz for your vehicle. Do not use any other valve caps or systems, e.g. tire pressure
monitoring systems.
Regularly check the pressure of all the tires par- ticularly prior to long trips. Adjust the tire pres-
sure as necessary (Y page 355).
Observe the notes on the emergency spare
wheel (Y page 378).
The service life of tires depends, among other
things, on the following factors:
R Driving style
R Tire pressure
R Distance covered Notes on tire tread
G
WARNING
If there is insufficient tire tread, the tire trac-
tion decreases. The tire tread is no longer able to dissipate water. This increases the risk of
hydroplaning when the road surface is wet,
particularly when the vehicle's speed is not
adapted to the road conditions. There is a risk
of an accident.
When the tire pressure is too high or too low,
tires may wear differently at different points
on the tire tread. Therefore, regularly check
the tire tread depth and the condition of the
tread across the whole width of all tires.
Minimum tire tread depth on:
R Summer tires: 00CEin (3 mm)
R M+S tires: 00CFin (4 mm)
For safety reasons, have the tires replaced
before they reach the legally prescribed min-
imum tire tread depth. Marking
0043shows where the bar indicator
(arrow) for tread wear is integrated into the tire
tread.
Treadwear indicators (TWI) are required by law. Six indicators are positioned on the tire tread.
They are visible once a tread depth of approx-
imately 00CDin (1.6 mm) has been reached. If this
is the case, the tire is so worn that it must be
replaced. Selecting, mounting and replacing
tires
R Only mount tires and wheels of the same type
and make.
Exception: it is permissible to mount a differ-
ent type or make in the event of a flat tire.
Observe here the "MOExtended tires (tires
with run-flat characteristics)" section
(Y page 336).
R Only mount tires of the correct size onto the
wheels.
R Break in new tires at moderate speeds for the
first 60 miles (100 km). The new tires only
reach their full performance after this dis-
tance.
R Do not drive with tires which have too little
tread depth. This significantly reduces the
traction on wet roads (hydroplaning).
R Replace the tires after six years at the latest,
regardless of wear.
Observe the notes on the emergency spare
wheel (Y page 378). MOExtended tires (tires with run-flat
properties)
With MOExtended tires (tires with run flat char- acteristics), you can continue to drive your vehi- Operation
353Wheels and tires Z