2015 MERCEDES-BENZ GL-Class ECU

Lowering the vehicle
If you maintain or reduce your speed, you will
see a message in white in the display while
the vehicle is being lowered, such as the fol-
lowing: Lowering Max. Speed 12 mph Lowering Max. Speed 12 mph
(20 km/h)
(20 km/h).
The vehicle is lowered to off-road level 2.
If you select an off-road level when driving at
too high a speed, the Drive More Slowly
Drive More Slowly
message appears in the multifunction dis-
play .
You can select from the following:
R Off-road level 1 at speeds up to 60 mph
(100 km/h)
R Off-road level 2 at speeds up to 40 mph
(65 km/h)
R Off-road level 3 at speeds up to 12 mph
(20 km/ h)
If you are driving above 50 mph (80 km/h) or
drive between 40 mph (65 km/h) and 50 mph
(80 km/h) for longer than 20 seconds, off-
road level 2 will be canceled. The vehicle is
lowered to off-road level 1.
You will see a message in the multifunction
display, for example: Lowering Lowering.
If you are driving above 70 mph (115 km/h) or drive between 62 mph (100 km/h) and
70 mph (115 km/h) for longer than
20 seconds, off-road level 1 will be canceled.
Depending on the vehicle's speed and the
ADS mode selected (Y page 220), the vehicle
is automatically lowered to highway or high-
speed level. You will see a message in the multifunction
display, for example:
Lowering
Lowering. HOLD function
General notes The HOLD function can assist the driver in the
following situations:
R when pulling away, especially on steep
slopes
R when maneuvering on steep slopes
R when waiting in traffic
The vehicle is kept stationary without the
driver having to depress the brake pedal.
The braking effect is canceled and the HOLD
function deactivated when you depress the
accelerator pedal to pull away.
i Do not use the HOLD function when driv-
ing off-road, on steep uphill or downhill gra-
dients or on slippery or loose surfaces. The HOLD function cannot hold the vehicle on
such surfaces.
Important safety notes G
WARNING
When leaving the vehicle, it can still roll away despite being braked by the HOLD function if:
R there is a malfunction in the system or in
the voltage supply.
R the HOLD function has been deactivated by
pressing the accelerator pedal or the brake
pedal, e.g. by a vehicle occupant.
R the electrical system in the engine com-
partment, the battery or the fuses have
been tampered with.
R the battery is disconnected
There is a risk of an accident.
If you wish to exit the vehicle, always turn off the HOLD function and secure the vehicle
against rolling away. 218
Driving systemsDriving and parking

!
If DISTRONIC PLUS or the HOLD function
is activated, the vehicle brakes automati-
cally in certain situations. To prevent dam-
age to the vehicle, deactivate DISTRONIC
PLUS and the HOLD function in the follow-
ing or other similar situations:
R when towing the vehicle
R in the car wash
Deactivating the HOLD function
(Y page 219).
Activation conditions You can activate the HOLD function if:
R
the vehicle is stationary
R the engine is running
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 D,Ror N
R DISTRONIC PLUS is deactivated
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 dis-
play.
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 automati-
cally if:
R you accelerate and the transmission is in
position Dor R.
R you shift the transmission to position P.
R you depress the brake pedal again with a
certain amount of pressure until 0043disap-
pears from the multifunction display.
R you secure the vehicle using the electric
parking brake.
R you activate DISTRONIC PLUS.
i After a time, the electric parking brake
secures the vehicle and relieves the service brake.
The electric parking brake automatically
secures the vehicle if the HOLD function is
activated and:
R the driver's door is open and the driver's
seat belt is unfastened.
R the engine is switched off.
R a system malfunction occurs.
R the power supply is not sufficient.
On steep uphill or downhill inclines or if there
is a malfunction, the transmission may also
be automatically shifted into position P. AIRMATIC package
General notes AIRMATIC regulates the level of your vehicle.
As well as level control (Y page 221), your
vehicle can be equipped with ADS (Adaptive
Damping System) (Y page 220) and ACTIVE
CURVE SYSTEM (Y page 220).
Observe the notes on driving with a trailer
(Y page 265). Driving systems
219Driving and parking Z

R
uphill or downhill gradient in percentage
R on-road/off-road program selected
R condition of the differential lock for the
transfer case
R the LOW RANGE off-road gear is selected
R condition of the LOW RANGE off-road
gear
R the on-road trailer program is selected Towing a trailer
Important safety notes
G
WARNING
Installing an unsuitable ball coupling may
result in overloading of the trailer tow hitch
and the rear axle. This applies especially if the ball coupling in question is longer or angled
differently. This could seriously impair the
driving characteristics and the trailer can
come loose. There is a risk of an accident.
You should only ever install a ball coupling
that has the permissible dimensions and that
is designed to meet your trailer-towing
requirements. Do not modify the ball coupling
or the trailer tow hitch.
You will find the values approved by the man-
ufacturer on the vehicle identification plates
and those for the towing vehicle under "Tech- nical data" (Y page 459). 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
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. 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.
! Depressing the brake pedal constantly
results in excessive and premature wear to
the brake pads.
Please observe the manufacturer's operating instructions for the trailer coupling if a
detachable 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. 264
Towing a trailerDriving and pa
rking

overheating and wearing too quickly. If you
need additional braking, depress the brake
pedal repeatedly rather than continuously.
Driving tips If the trailer swings from side to side:
X Do not accelerate.
X Do not counter-steer.
X Brake if necessary.
R Maintain a greater distance from the vehi-
cle in front than when driving without a
trailer.
R Avoid braking abruptly. If possible, brake
gently at first to allow the trailer to run on.
Then, increase the braking force rapidly.
R The values given for gradient-climbing
capabilities from a standstill refer to sea
level. When driving in mountainous areas,
note that the power output of the engine
and, consequently, the vehicle's gradient-
climbing capability, decreases with
increasing altitude. Installing the ball coupling
G
WARNING
If the ball coupling is not correctly installed
and secured, it can come loose during the
journey and endanger other road users. There is a risk of an accident and injury.
Always install and secure the ball coupling as
described. Before every journey, ensure that
the ball coupling is secured with the bolt and
the corresponding spring cotter. G
WARNING
If the ball coupling is not installed correctly or not secured with the bolt provided and the
corresponding spring cotter, the trailer may
come loose. There is a risk of an accident.
Always install and secure the ball coupling as
described. Before every journey, ensure that
the ball coupling is secured with the bolt and
the corresponding spring cotter. G
WARNING
If the ball coupling is not installed and secured
correctly the trailer may come loose. There is
a risk of an accident.
Install and secure the ball coupling as descri-
bed in the ball coupling installation instruc-
tions. Make sure that the ball coupling is
installed and secured correctly before every
journey. Cover cap
X Pull protective cap 0043in the direction of the
arrow, out of the ball coupling recess.
X Place protective cap 0043in the ball coupling
recess. 266
Towing a trailerDriving and parking

Ball coupling recess
Holes in the ball coupling and ball coupling recess
X Insert the ball coupling horizontally into ball
coupling recess 0044in the direction of the
arrow until the holes in ball coupling 0087are
in line with the holes in ball coupling
recess 0085. Bolt
X Slide bolt 0083into the hole in the ball cou-
pling recess and the ball coupling to the
stop. Bolt and spring cotter
X Secure the bolt using spring cotter 0084. Correctly installed and secured ball coupling
X Check the ball coupling, bolt and spring
cotter for correct installation.
If the ball coupling cannot be correctly moun-
ted, remove the ball coupling. Under these
circumstances, the ball coupling must not be used for trailer towing.
If the ball coupling cannot be locked and the
key cannot be removed, remove the ball cou-
pling and clean it. If the ball coupling can still
not be installed (locked) after it has been
cleaned, remove the ball coupling. The trailer tow hitch must then not be used to tow a
trailer, as safe operation cannot be guaran-
teed.
Have the entire trailer tow hitch checked at aqualified specialist workshop. Coupling up a trailer
! Do not connect the trailer's brake system
(if featured) to the hydraulic brake system Towing a trailer
267Driving and parking Z

using the brake controller and check
whether the brakes function correctly.
R Secure any objects on the trailer to prevent
the cargo from slipping when the vehicle is
in motion.
R When you couple up a trailer, check at reg-
ular intervals that the load is firmly secured.If the trailer is equipped with trailer lights
and brakes, check the trailer to ensure that
these are working.
R Bear in mind that the handling will be less
stable when towing a trailer than when driv- ing without one. Avoid sudden steering
movements.
R The vehicle/trailer combination is heavier,
accelerates more slowly, has a decreased
gradient climbing capability and a longer
braking distance.
It is more susceptible to side winds and
requires more careful steering.
R If possible, do not brake suddenly, but
instead depress the brake pedal moder-
ately at first so that the trailer can activate its brakes. Then increase the pressure on
the brake pedal.
R If the automatic transmission repeatedly
shifts between gears on uphill or downhill
gradients, shift to a lower gear using the
left-hand steering wheel paddle shifter.
A lower gear and lower speed reduce the
risk of engine failure.
R When driving downhill, shift to a lower gear
to utilize the engine's braking effect.
Avoid continuous brake application as this
may overheat the vehicle brakes and, if
installed, the trailer brakes.
R If the coolant temperature increases dra-
matically while the air-conditioning system
is switched on, switch off the air-condition-
ing system.
Coolant heat can also be dissipated by
opening the windows and switching the ventilation blower and the interior temper-
ature to the highest level.
R When overtaking, pay particular attention
to the extended length of your vehicle/
trailer combination.
Due to the length of the vehicle/trailer
combination, you require additional road
space in relation to the vehicle you are
overtaking before you can change back to
the original lane. Decoupling a trailer
G
WARNING
If you uncouple a trailer with the overrun
brake engaged, you could trap your hand
between the vehicle and the trailer drawbar.
There is a risk of injury.
Do not uncouple a trailer if the overrun brake is engaged. G
WARNING
Vehicles with level control:
The vehicle is lowered as soon as you discon-
nect the trailer cable. This could result in your limbs or those of other people that are
between the vehicle body and tires or under-
neath the vehicle being trapped. There is a
risk of injury.
Make sure that nobody is in the immediate
vicinity of the wheel housings or under the
vehicle when you disconnect the trailer cable.
! Do not disconnect a trailer with an
engaged overrun brake. Otherwise, your
vehicle could be damaged by the rebound- ing of the overrun brake.
X Make sure that the automatic transmission
is set to position P.
X Apply the vehicle's electric parking brake.
X Start the engine.
X Close all doors and the tailgate.
X Apply the trailer's parking brake. Towing a trailer
269Driving and parking Z

X
Detach the trailer cable and decouple the
trailer.
X Switch off the engine. Permissible trailer loads and drawbar
loads
Weight specifications Maximum permissible gross vehicle
weight rating
The gross trailer weight is calculated by add-
ing the weight of the trailer to the weight of
the load and equipment on the trailer.
You will find installing dimensions and loads
under "Technical data" (Y page 458).
Permissible noseweight
You will find installing dimensions and loads
under "Technical data" (Y page 458).
Loading a trailer R
When loading the trailer, make sure that
neither the permissible gross weight of the
trailer nor the gross vehicle weight is
exceeded. The permissible gross vehicle
weight is indicated on the identification
plate on the B-pillar on the driver's side of
the vehicle.
You can find the maximum permissible val-
ues on the type plates of your vehicle and
the trailer. When calculating how much
weight the vehicle and trailer may carry,
pay attention to the respective lowest val-
ues.
R The trailer drawbar load on the ball coupling
must be added to the rear axle load to avoid exceeding the permissible gross axle
weight. The permissible gross vehicle
weight is indicated on the identification
plate on the B-pillar on the driver's side of
the vehicle.
i Mercedes-Benz recommends a trailer
load where the trailer drawbar noseweight accounts for 8% to 15% of the trailer's per-
missible gross weight.
i The weight of additional accessories, pas-
sengers, and cargo reduces the permissi-
ble trailer load and drawbar load for your
vehicle.
Checking the vehicle and trailer weight R
To check that the weights of the towing
vehicle and the trailer comply with the max-
imum permissible values, have the vehicle/
trailer combination (including the driver,
passengers, and cargo with a fully laden
trailer) weighed on a calibrated weigh-
bridge.
R Check the gross axle weight rating of the
front and rear axles, the gross weight of the
trailer and trailer drawbar load. Removing the ball coupling
X Remove the spring cotter.
X Remove the bolt from the ball coupling
recess.
X Remove the ball coupling from the ball cou-
pling recess.
X Clean the ball coupling if it is dirty.
X Stow the ball coupling so that it cannot be
thrown around.
Observe the loading guidelines (Y page 342)
and the safety notes regarding stowage
spaces (Y page 343).
Information on cleaning and care of the trailer tow hitch can be found at (Y page 382). Storing the ball coupling
G
WARNING
Do not carry the ball coupling in the vehicle
interior if it is not secured.
Otherwise, you and others could be injured by the ball coupling being thrown around if you: 270
Towing a trailerDriving an
d parking

Display messages
Possible causes/consequences and
0050
0050Solutions The red
0049(USA only)/0024 (Canada only) indicator lamp
flashes and the yellow 0024warning lamp lights up.
The electric parking brake is malfunctioning.
To release:
X Switch off the ignition and turn it back on.
X Release the electric parking brake manually.
To apply: X Switch off the ignition and turn it back on.
X Apply the electric parking brake manually.
If the red 0049(USA only)/ 0024(Canada only) indicator lamp
continues to flash:
X Do not drive on.
X Secure the vehicle against rolling away (Y page 430).
X Shift the transmission to P.
X Turn the front wheels towards the curb.
X Consult a qualified specialist workshop. The yellow
0024warning lamp lights up. The red 0049(USA
only)/ 0024(Canada only) indicator lamp flashes for about ten
seconds after the electric parking brake has been applied or
released. It then goes out or remains lit.
The electric parking brake is malfunctioning.
X Switch off the ignition and turn it back on.
X Apply the electric parking brake.
If it is not possible to engage the electric parking brake:
X Shift the transmission to P.
X Visit a qualified specialist workshop.
If it is not possible to release the electric parking brake:
X Release the electric parking brake automatically (Y page 192).
If the electric parking brake still cannot be released: X Consult a qualified specialist workshop. Display
messages
297On-board computer and displays Z