2019 MERCEDES-BENZ GLS SUV towing

To avoid damage to the vehicle, deactivate
Active Distance Assist DISTRONIC and the
HOLD function in the following or similar sit-
uations:
R when towing the vehicle
R in the car wash
Active Distance Assist DISTRONIC:
R Can neither reduce the risk of accident nor
override the laws of physics if you fail to adapt
your driving style.
R Cannot take into account road, weather or
traffic conditions.
R Is only an aid.
You are responsible for the distance to the vehi-
cle in front, for vehicle speed, for braking in good
time and for staying in your lane.
Do not use Active Distance Assist DISTRONIC:
R In road and traffic conditions which do not
allow you to maintain a constant speed, e.g. in
heavy traffic or on winding roads
R On icy or slippery roads; braking or acceler-
ating can cause the drive wheels to lose trac-
tion and the vehicle could then skid
R In poor visibility, e.g. due to fog, heavy rain or
snow
Active Distance Assist DISTRONIC may not
detect narrow vehicles driving in front, e.g.
motorcycles, or vehicles driving in a staggered
formation.
In particular, the detection of obstacles can be
impaired if:
R There is dirt on the sensors or anything else
covering the sensors
R There is snow or heavy rain
R There is interference by other radar sources
R There are strong radar reflections, for exam-
ple in parking garages
If Active Distance Assist DISTRONIC no longer
detects a vehicle in front, Distance Pilot
DISTRONIC may unexpectedly accelerate to the
speed stored.
This speed may:
R Be too high if you are driving in a turning lane
or an exit lane
R Be so high when driving in the right-hand lane
that you overtake vehicles in the left-hand
lane
R Be so high in the left lane that you pass vehi-
cles driving on the right If there is a change of drivers, advise the new
driver of the speed stored.
Cruise control lever 0043
Activates or increases speed
0044 Activates or reduces speed
0087 Deactivates Active Distance Assist
DISTRONIC
0085 Activates at the current speed or last stored
speed
0083 Sets a specified minimum distance
Activating Active Distance Assist
DISTRONIC Activation conditions
To activate Active Distance Assist DISTRONIC,
the following conditions must be fulfilled:
R the engine must be started. It may take up to
two minutes of driving before Active Distance Assist DISTRONIC is ready for use.
R the electric parking brake must be released.
R ESP ®
must be active, but not intervening.
R the transmission must be in position 005B.
R the driver's door must be closed when you
shift from 005Dto005B or your seat belt must be
fastened.
R the front-passenger door and rear doors must
be closed.
R the Offroad Plus drive program must be deac-
tivated (vehicles with the Off-road Engineer-
ing Package).
R DSR must be deactivated.
R the vehicle must not skid. 174
Driving systemsDriving and parking

R
the distance to the vehicle in front is too short
and thus the lane markings cannot be detec-
ted
R the lane markings change quickly, e.g. lanes
branch off, cross one another or merge
R the road is narrow and winding
R there are highly variable shade conditions on
the roadway
The system is switched to passive and no longer assists you by performing steering interventions
if:
R you actively change lane
R you switch on the turn signal
R you take your hands off the steering wheel or
do not steer for a prolonged period of time
i Once you have finished changing lanes,
Active Steering Assist automatically reacti-
vates.
Active Steering Assist cannot provide assis-
tance:
R on very sharp corners
R when towing a trailer
R when a loss of tire pressure or a defective tire
has been detected and displayed
Observe the important safety notes on Active
Distance Assist DISTRONIC (Y page 173).
The steering interventions are carried out with a limited steering moment. The system requires
the driver to keep his hands on the steering
wheel and to steer himself.
If you do not steer yourself or if you take your
hands off the steering wheel for a prolonged
period of time, the system will first alert you with
a visual warning. A steering wheel symbol
appears in the multifunction display. If you have
still not started to steer and have not taken hold of the steering wheel after five seconds at the
latest, a warning tone also sounds to remind you
to take control of the vehicle. Active Steering
Assist is then switched to passive. Active Dis-
tance Assist DISTRONIC remains active.
Activating Active Steering Assist X Select the Active Distance Assist DISTRONIC
with Active Steering Assist function using the
on-board computer (Y page 238).
The Active
Active Steering Steering Assist
AssistOn
Onmessage
appears on the multifunction display. Active
Steering Assist is activated. Information in the multifunction display
If Active Steering Assist is activated but not
ready for a steering intervention, steering wheel
symbol 0043appears in gray. If the system pro-
vides you with support by means of steering
interventions, symbol 0043is shown in green.
Deactivating Active Steering Assist
X Deactivate the Active Distance Assist
DISTRONIC with Active Steering Assist func-
tion using the on-board computer
(Y page 238).
The Active Steering Assist Off Active Steering Assist Off mes-
sage appears on the multifunction display.
Active Steering Assist is deactivated.
When Active Distance Assist DISTRONIC is
deactivated or not available, Active Steering
Assist is deactivated automatically. Level control (vehicles with the Off-
Road Engineering package)
Important safety notes Level control adapts the vehicle level automati-
cally to the current operating and driving situa-
tion. This results in reduced fuel consumption
and improved handling.
Make changes to the vehicle level while the
vehicle is in motion. This enables the vehicle to adjust to the new level as quickly as possible.
The vehicle level may change visibly if you park
the vehicle and the outside temperature
changes. If the temperature drops, the vehicle
level is lower; with an increase in temperature,
the vehicle level rises.
If you unlock the vehicle or open a door, the
vehicle begins to compensate for load discrep-
ancies while still parked. However, for signifi-
cant level changes, such as after the vehicle has
been stationary for a long period, the engine
must be on. For safety reasons, the vehicle is
only lowered when the doors are closed. Low- 180
Driving systemsDriving an
d parking

i
Do not use the HOLD function when driving
off-road, on steep uphill or downhill gradients or on slippery or loose surfaces. The HOLD
function cannot hold the vehicle on such sur- faces.
Important safety notes G
WARNING
If the vehicle is only braked using the HOLD
function, the vehicle may roll away in the fol-
lowing situations when you leave the vehicle:
R if there is a malfunction in the system or in
the voltage supply
R if the HOLD function is deactivated by
depressing the accelerator pedal or brake
pedal, e.g. by a vehicle occupant
There is a risk of an accident.
Always deactivate the HOLD function and
secure the vehicle against rolling away before
you leave it.
! When Active Distance Assist DISTRONIC or
the HOLD function is activated, the vehicle
brakes automatically in certain situations.
To avoid damage to the vehicle, deactivate
Active Distance Assist DISTRONIC and the
HOLD function in the following or similar sit-
uations:
R when towing the vehicle
R in the car wash
Deactivate the HOLD function (Y page 184).
Activation conditions You can activate the HOLD function if:
R the vehicle is stationary
R the engine is running or if it has been auto-
matically switched off by the ECO start/stop
function
R the driver's door is closed or your seat belt is
fastened
R the electric parking brake is released
R the transmission is in position 005B,005Eor005C
R Active Distance Assist DISTRONIC is deacti-
vated Activating the HOLD function X
Make sure that the activation conditions are
met.
X Depress the brake pedal.
X Quickly depress the brake pedal further
until 0043appears in the multifunction display.
The HOLD function is activated. You can
release the brake pedal.
i If depressing the brake pedal the first time
does not activate the HOLD function, wait
briefly and then try again.
Deactivating the HOLD function The HOLD function is deactivated automatically
if:
R you depress the accelerator and the trans-
mission is in position 005Bor005E
R you shift the transmission to position 005D
R you depress the brake pedal again with a cer-
tain amount of pressure until 0043disappears
from the multifunction display
R you secure the vehicle using the electric park-
ing brake
R you activate Active Distance Assist
DISTRONIC
i After a time, the electric parking brake
secures the vehicle and relieves the service
brake.
When the HOLD function is activated, the trans-
mission is automatically shifted to position 005D
if:
R the driver's door is open and the driver's seat
belt is unfastened
R the engine is switched off, unless it is auto-
matically switched off by the ECO start/stop
function 184
Driving systemsDriving an
d parking

If the lanes are narrow, vehicles driving in the
lane beyond the lane next to your vehicle may be
indicated, especially if the vehicles are not driv-
ing in the middle of their lane. This may be the
case if there are vehicles driving at the inner
edge of their lanes.
Due to the nature of the system:
R warnings may be issued in error when driving
close to crash barriers or similar solid lane
borders.
R the warning is canceled when driving for an
extended period next to long vehicles, such as
trucks.
Warning lamp
Blind Spot Assist is not active at speeds below
approximately 20 mph (30 km/h). Vehicles in
the monitoring range are then not indicated. 0043
Warning lamp
If Blind Spot Assist is activated, warning lamp 0043
in the exterior mirrors lights up yellow at speeds
of up to 20 mph (30 km/h). At speeds above
20 mph (30 km/h), the warning lamp goes out
and Blind Spot Assist is operational.
If a vehicle is detected within the blind spot
monitoring range at speeds above 20 mph
(30 km/h), warning lamp 0043on the correspond-
ing side lights up red. This warning is always
emitted when a vehicle enters the blind spot
monitoring range from behind or from the side.
When you overtake a vehicle, the warning only
occurs if the difference in speed is less than
7 mph (12 km/h).
If you select the reverse gear, Blind Spot Assist
is not operational.
The brightness of the warning lamps is auto-
matically adapted to the brightness of the sur-
roundings. Collision warning
If a vehicle is detected in the monitoring range of
Blind Spot Assist and you switch on the corre-
sponding turn signal, a double warning tone
sounds. Red warning lamp 0043flashes. If the turn
signal remains on, detected vehicles are indica-
ted by the flashing of red warning lamp 0043.
There are no further warning tones.
Switching on Blind Spot Assist X Make sure that Blind Spot Assist is activated
in the on-board computer (Y page 239).
X Turn the SmartKey to position 0048in the igni-
tion lock.
Warning lamps 0043in the exterior mirrors light
up red for approximately 1.5 seconds and
then turn yellow.
Towing a trailer
When you attach a trailer, make sure you have
correctly established the electrical connection.
This can be accomplished by checking the trailer
lighting. In this event, Blind Spot Assist is deac-
tivated. The warning lamp lights up yellow in the
exterior mirrors and the Blind Spot Assist
Blind Spot Assist
Not Available When Towing a Trailer Not Available When Towing a Trailer
See Operator's Manual See Operator's Manual message appears in
the multifunction display.
i You can deactivate the warning lamps in the
exterior mirrors.
To do so, switch off Blind Spot Assist when:
R the SmartKey is in position 0048in the igni-
tion lock
R the engine is not running
Lane Keeping Assist General notes
0043
Lane Keeping Assist camera 208
Driving systemsDriving and parking

Visual and acoustic collision warning
If you switch on the turn signals to change lanes
and a vehicle is detected in the side monitoring range, you receive a visual and acoustic collision
warning. You then hear a double warning tone
and red warning lamp 0043flashes. If the turn sig-
nal remains on, detected vehicles are indicated
by the flashing of red warning lamp 0043. There are
no further warning tones.
Course-correcting brake application If Active Blind Spot Assist detects a risk of a lat-
eral collision in the monitoring range, a course-
correcting brake application is carried out. This is meant to assist you in avoiding a collision. G
WARNING
A course-correcting brake application cannot always prevent a collision. There is a risk of an
accident.
Always steer, brake or accelerate yourself,
especially if Active Blind Spot Assist warns
you or makes a course-correcting brake appli-
cation. Always maintain a safe distance at the sides.
If a course-correcting brake application occurs, red warning lamp 0043flashes in the exterior mir-
ror and a double warning tone sounds. In addi-
tion, a display underlining the danger of a side
collision appears in the multifunction display.
In very rare cases, the system may make an
inappropriate brake application. A course-cor-
recting brake application may be interrupted at
any time by countersteering slightly or acceler-
ating.
The course-correcting brake application is avail-
able in the speed range between 20 mph
(30 km/h) and 120 mph (200 km/h).
Either no braking application, or a course-cor-
recting brake application adapted to the driving situation occurs if:
R there are vehicles or obstacles, e.g. crash
barriers, located on both sides of your vehicle.
R a vehicle approaches you too closely at the
side.
R you have adopted a sporty driving style with
high cornering speeds.
R you clearly brake or accelerate.
R a driving safety system intervenes, e.g. ESP ®
or PRE-SAFE ®
Brake. R
ESP ®
is switched off.
R the offroad program is activated (vehicles
without the Offroad Engineering package).
R the Offroad or Offroad Plus drive program is
activated (vehicles with the Off-Road Engi-
neering package).
R the LOW RANGE offroad gear is activated
(vehicles with the Offroad Engineering pack-
age).
R a loss of tire pressure or a defective tire is
detected.
Switching on Active Blind Spot Assist
X Make sure that Active Blind Spot Assist
(Y page 239) is activated in the on-board
computer.
X Turn the SmartKey to position 0048in the igni-
tion lock.
Warning lamps 0043in the exterior mirrors light
up red for approximately 1.5 seconds and
then turn yellow.
Towing a trailer
When you attach a trailer, make sure you have
correctly established the electrical connection.
This can be accomplished by checking the trailer
lighting. Active Blind Spot Assist is then deacti-
vated. The indicator lamp lights up yellow in the
exterior mirrors and the Active Blind Spot
Active Blind Spot
Asst. Not Available When Towing a Asst. Not Available When Towing a
Trailer See Operator's Manual
Trailer See Operator's Manual message
appears in the multifunction display.
Active Lane Keeping Assist General notes
Active Lane Keeping Assist monitors the area in
front of your vehicle by means of multifunction
camera 0043at the top of the windshield. Various
different areas to the front, rear and side of your 212
Driving systemsDriving and parking

R
you switch on the turn signals. In this event,
the warnings are suppressed for a certain
period of time.
R a driving safety system intervenes, such as
ABS, BAS or ESP ®
.
When Adaptive
Adaptive is selected, no warning vibra-
tion occurs if:
R you switch on the turn signals. In this event,
the warnings are suppressed for a certain
period of time.
R a driving safety system intervenes, e.g.
ABS, BAS or ESP ®
.
R you accelerate hard, e.g. kickdown.
R you brake hard.
R you steer actively, e.g. swerve to avoid an
obstacle or change lanes quickly.
R you cut the corner on a sharp bend.
Towing a trailer
When you attach a trailer, make sure you have
correctly established the electrical connection.
This can be accomplished by checking the trailer
lighting. Lane-correcting brake application does not take place when towing a trailer. Active Lane
Keeping Assist is not activated and the lines in
the assistance graphic are gray. Off-road driving systems
4MATIC (permanent four-wheel drive) 4MATIC ensures that all four wheels are perma-
nently driven. Together with ESP ®
and 4ETS, it
improves the traction of your vehicle whenever
a drive wheel spins due to insufficient grip.
If you fail to adapt your driving style, 4MATIC can
neither reduce the risk of accident nor override
the laws of physics. 4MATIC cannot take
account of road, weather and traffic conditions. 4MATIC is only an aid. You are responsible for
the distance to the vehicle in front, for vehicle
speed, for braking in good time and for staying in
your lane.
! Never tow the vehicle with one axle raised.
This may damage the transfer case. Damage
of this sort is not covered by the Mercedes-
Benz Limited Warranty. All wheels must
remain either on the ground or be fully raised. Observe the instructions for towing the vehi-
cle with all wheels in full contact with the
ground. !
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 166).
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 005B,005E
or 005C. 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- Driving systems
215Driving and parking Z

006D
Level control
006E Compass with angle scale
Activating the driving dynamics display X
Switch on COMAND (see the Digital Opera-
tor's Manual).
X Press button 0043.
The driving dynamics display appears in the
COMAND display. Towing a trailer
Important safety notes
G
WARNING
Installing an unsuitable ball coupling may
overload the trailer tow hitch and the rear
axle. This is particularly likely in the case of
longer or differently angled ball couplings.
Consequently, the driving characteristics may
be significantly impaired and the trailer may
detach. This presents the risk of an accident
or even fatal injuries!
Install only a ball coupling that adheres to the permissible dimensions and is designed for
your intended purpose for towing a trailer. Do
not make any changes to the ball coupling or the trailer tow hitch.
You will find the values approved by the manu-
facturer on the vehicle identification plates and
those for the towing vehicle under "Technical
data" (Y page 392). 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.
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
When the vehicle/trailer combination begins
to lurch, you could lose control of it. The vehi- cle/trailer combination could even rollover.
There is a risk of an accident.
On no account should you attempt to
straighten up the vehicle/trailer combination
by increasing the speed. Reduce vehicle
speed and do not countersteer. Apply the
brake as necessary.
Please observe the manufacturer's operating
instructions for the trailer coupling if a detach-
able trailer coupling is used.
Couple and uncouple the trailer carefully. If you do not couple the trailer to the towing vehicle
correctly, the trailer could become detached.
Make sure that the following values are not
exceeded:
R the permissible trailer drawbar noseweight
R the permissible trailer load
R the permissible rear axle load of the towing
vehicle
R the maximum permissible gross vehicle
weight of both the towing vehicle and the
trailer
The applicable permissible values, which must
not be exceeded, can be found:
R in the vehicle documents
R on the identification plates for the trailer tow
hitch and the trailer
R on the vehicle identification plate
If the values differ, the lowest value applies.
When towing a trailer, your vehicle's handling
characteristics will be different in comparison
with when driving without a trailer.
The vehicle/trailer combination:
R is heavier
R is restricted in its acceleration and gradient-
climbing capability
R has an increased braking distance Towing a trailer
221Driving and parking Z

R
is affected more by strong crosswinds
R demands more sensitive steering
R has a larger turning circle
This could impair the handling characteristics.
When towing a trailer, always adjust your speed to the current road and weather conditions. Do
not exceed the maximum permissible speed for
your vehicle/trailer combination. Notes on towing a trailer
General notes !
If you have a trailer tow hitch retrofitted,
changes to the cooling system and drive train may be necessary, depending on the vehicle
type.
If you have a trailer tow hitch retrofitted,
observe the anchorage points on the chassis
frame.
R Do not exceed the legally prescribed maxi-
mum speed for vehicle/trailer combinations
in the relevant country.
This lowers the risk of an accident.
R Only install an approved trailer coupling on
your vehicle.
More information on availability and installa-
tion can be obtained at any qualified special-
ist workshop.
R The bumpers of your vehicle are not suitable
for installing detachable trailer couplings.
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 371).
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 189)
R Blind Spot Assist (Y page 207)
R Active Lane Keeping Assist (Y page 212)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 392).
Driving tips Also observe the notes on pulling away with a
trailer (Y
page 143).
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 for your trailer. Observe the
legally permissible maximum speed in the rele-
vant 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 392). 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 maximum
permissible speed for car/trailer combinations
is greater than 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 lower gear in good time on long
and steep downhill gradients.
This also applies if you have activated cruise
control or Active Distance Assist 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. 222
Towing a trailerDriving and parking