2012 MERCEDES-BENZ GL wheel

or be fully raised. Observe the instructions
for towing the vehicle with all wheels in full
contact with the ground.
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.
! When testing the parking brake, operate
the vehicle only briefly (for a maximum of
ten seconds) on a brake test dynamometer.
When doing this, turn the key to position
0 or 1 in the ignition. Failure to do this can
cause damage to the drive train or the
brake system.
! Function or performance tests may only
be performed on a 2-axle dynamometer. If
you wish to operate the vehicle on such a
dynamometer, please consult an
authorized Mercedes-Benz Center
beforehand. You could otherwise damage
the drive train or the brake system.
For information about driving off-road, see
( Y page 174).
DSR (Downhill Speed Regulation)
Important safety notes
DSR is an aid to assist you when driving
downhill. It keeps the speed of travel at the
speed selected on the on-board computer.
The steeper the downhill gradient, the greater
the DSR braking effect on the vehicle. When
driving on flat stretches of road or on an uphill
gradient, the DSR braking effect is minimal or
non-existent.
The set speed is set to 4 mph (6 km/h) at the
factory; this can be adjusted using the on-
board computer ( Y page 228).
GWARNING
Downhill Speed Regulation (DSR) is a
convenience system designed to assist the
driver during vehicle operation. The system
setting must be appropriate to the
topographical and weather conditions
encountered, which can change quickly. The
driver is responsible for the vehicle speed and
for safe brake operation at all times.
Depending on the programmed speed, actual
vehicle speed and gradient, switching on DSR
while driving can cause the vehicle to slow
down rapidly, and you may hear a sound,
caused by the activation of the vehicle's brake
system through DSR. Sudden and unexpected
deceleration can result in loss of vehicle
control, causing an accident and/or serious
personal injury to you and others. Do not
switch on DSR in a situation where rapid
deceleration could result in a loss of vehicle
control.
DSR controls the set speed when it is active
and the automatic transmission is in the D,
R or N position. 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.GWARNING
If you depress the accelerator pedal with DSR
activated, the vehicle can drive faster than the
programmed set speed. You should therefore
drive downhill with particular caution as it
could lead to an accident and/or serious
injury to you or others. Keep in mind that as
soon as you remove your foot from the
accelerator pedal with DSR switched on, DSR
will start regulating the vehicle's speed
including use of brakes if required. Depending
on the programmed set speed, actual vehicle
speed and gradient, DSR can cause the
vehicle to slow down rapidly. Sudden and
unexpected deceleration can result in loss of
vehicle control, causing an accident and/or
serious personal injury to you and others.
For information about driving off-road, see
( Y page 174).
204Off-road driving systemsDriving and parking

Off-road drive program
i The off-road drive program is available
only in vehicles without the Off-Road Pro
engineering package.
The off-road drive program assists you in
driving off-road. The engine’s performance
characteristics and the gearshifting
characteristics of the automatic transmission
are adapted for this purpose. ABS, ESP ®
and
4 ETS programs especially adapted to off-
road driving are also activated.
Do not use the off-road drive program on
roads that are covered in snow or icy or if you
have installed snow chains on your vehicle.
For information about driving off-road, see
( Y page 174).XTo activate: press off-road button :.
Indicator lamp ; lights up. Off-road
indicator = appears in the multifunction
display.XTo activate: press off-road button :.
Indicator lamp ; and off-road indicator
= go out.LOW RANGE off-road gear
General notes
The LOW RANGE off-road gear assists you in
driving off-road and when fording. When LOW
RANGE is engaged, the engine’s performance
characteristics and the gearshifting
characteristics of the automatic transmission
are adapted for this purpose. ABS, ESP ®
and
4 ETS programs especially adapted to off-
road driving are also activated.
Information on "Off-road driving"; see
( Y page 174) . You will find information about
driving safety systems in conjunction with
LOW RANGE in the "Safety" section
( Y page 67).
Shift ranges
HIGH RANGERoad position for all
normal driving situationsLOW RANGEOff-road position for
driving off-road and
fording
The gear ratio between the
engine and wheels is only
approximately one third of
that in the HIGH RANGE
road position. The drive
torque is correspondingly
higher as a result.
Do not use LOW RANGE:
R on slippery road
surfaces, e.g. in the case
of slush
R on snow or ice-covered
roads
R if you have snow chains
on your vehicleGWARNING
Always wait until the procedure of shifting
from HIGH RANGE to LOW RANGE – and from
LOW RANGE to HIGH RANGE – has been
entirely completed. During this procedure do
206Off-road driving systemsDriving and parking

process has not been completed. LOW
RANGE is in the neutral position. There is no
connection between the engine and the drive
wheels.
! Do not drive any further, otherwise you
could damage the vehicle’s drive train.XStop the vehicle. Take into account the
road and traffic conditions when doing this.XDepress the parking brake.XCarry out the gear change process again.
If the gear change process has been carried
out, the Stop vehicle Apply parking
brake message disappears.
Differential lock
General notes
i Differential locks are available only in
vehicles with the Off-Road Pro engineering
package.
Your vehicle is equipped with the following:
R A differential lock for the transfer box: this
controls the balance between the front and
rear axles.
R A differential lock for the rear axle: this
controls the balance between the wheels
and the rear axle.
Differential locks improve the vehicle's
traction. 4ETS ( Y page 70) controls the
balance between the wheels on the front axle.
For information about driving off-road, see
( Y page 174).
Information on differential and
differential locks
When the vehicle drives around a corner, the
wheels on the outside of the bend must cover
a greater distance and must therefore turn
more rapidly than the wheels on the inside.
The differential, a transmission in the drive
train, compensates for these different
rotational speeds, making cornering possible.
A differential has the disadvantage that the
wheels with the least road grip are driven with
the greatest force. An example: a wheel of a
driven axle is on a snow-covered surface and
therefore does not have any traction. The
differential causes this wheel to be subjected
to the strongest driving force, as the flow of
force takes the path of least resistance. On
the other hand, the opposite wheel on this
axle, which is located on a firm surface and
could therefore make traction possible, does
not receive any driving force. 4ETS rectifies
this disadvantage and provides good
steerability by braking the spinning wheel
automatically and therefore channeling more
driving force to the wheel that is on a firm
surface and that can therefore supply
traction.
ESP ®
and 4ETS are traction systems that are
ideally suited for driving on roads and on
gentle terrain. The LOW RANGE off-road gear
also improves off-road capability.
Difficult terrain conditions require further
more extensive measures such as the locking
of one or more differentials. Your vehicle is
equipped with two differential locks: one
(central) differential lock for the transfer case
and one differential lock for the rear axle.
Each differential lock can be activated with
the selector wheel on the center console.
When the (central) differential for the transfer
case is locked, the speed of the front wheels
is just as high as the speed of the rear wheels.
If the differential for the rear axle is locked,
both rear wheels turn at the same speed,
regardless of their individual torques. Please
note that activating the differential locks
severely restricts the vehicle's steerability.
For your own safety, the safety of others and
to prevent damage to your vehicle, the
differential locks must not be activated on
paved roads. Please note that the function of
the differential is absolutely necessary for
driving on paved roads and that the
differentials must not be locked on paved
roads under any circumstances. The
steerability of the vehicle would otherwise be208Off-road driving systemsDriving and parking

lost and steering would no longer be possible.
The differential locks must therefore only be
activated off-road and only if activating the
other driving systems (4ETS, ESP ®
and LOW
Range off-road gear) is no longer sufficient.
Engaging the differential locks
! Pull away slowly when the differential
locks are activated.
Function or performance tests may only be
performed on a 2-axle dynamometer. If you
wish to operate the vehicle on such a
dynamometer, please consult an
authorized Mercedes-Benz Center
beforehand. You could otherwise damage
the drive train or the brake system.
Automatic mode
Use automatic mode ; for all driving
situations, including driving off-road or when
fording.
In automatic mode, the differential locks are
engaged and disengaged according to driving
requirements. This guarantees sufficient
traction for most driving situations with
unrestricted vehicle steerability.
XStart the engine.
The differential locks are in automatic
mode. The indicator lamp in selector
wheel : lights up above symbol for
automatic mode ;.Engaging manuallyGWARNING
Never drive on a paved surface with the center
and rear axle differential locks manually
engaged. Ability to steer the vehicle is greatly
reduced when the differential locks are
manually engaged, increasing the risk of an
accident.
For safety reasons, the locks are
automatically released at a vehicle speed
above 31 mph (50 km/h). Nevertheless, you
should only manually lock the differential if
absolutely necessary because engaged locks
will restrict the vehicle drivetrain while
cornering and cause the vehicle to chatter.
This could cause you to lose control of the
vehicle and cause an accident.
! The differential locks must not be
activated when the vehicle is being towed
or while the wheels are spinning.
Only engage the differential locks manually if
traction in automatic mode is insufficient.
The differential locks can be activated
manually up to a speed of 19 mph
(30 km/h).
XStart the engine.XTurn selector wheel : to desired position
= or ?.
The indicator lamp in selector wheel :
lights up at the corresponding symbol.
The engaged differential appears in the
multifunction display:
AThe differential lock for the transfer case
is locked.
If you have not previously selected the off-
road menu ( Y page 222) in the on-board
Off-road driving systems209Driving and parkingZ

computer, the message disappears after
about five seconds.
The differential locks are not controlled
automatically. The steerability of the vehicle
is restricted considerably. Drive carefully and
accelerate gently for optimum traction.
! If the differential locks are activated
manually, the wheels scuff on the road
when cornering since the rotation
difference between the wheels is no longer
balanced out.
You can switch back to automatic mode at
any time. For safety reasons, the differential
locks are deactivated automatically at speeds
over 31 mph (50 km/h). If you stop the
vehicle and switch off the ignition for longer
than ten seconds, the differential locks
switch back to automatic mode.
Message in the multifunction display
Diff. lock system overheated.
Wait briefly.
The differential lock system has overheated
and briefly disengaged.XContinue driving.
The differential locks cool off and are soon
available once again.
Trailer towing
Notes on towing a trailer
Important safety notes
GWARNING
When towing a trailer, incorrect equipment
and driving style could cause you to lose
control of the vehicle.
Towing incorrectly or not observing this
Operator's Manual could lead to damage to
the vehicle and/or serious injuries. Observe
the following guidelines to ensure safe trailer
towing.
Contact a Mercedes-Benz Center if you need
further explanation of the information
contained in this Operator's Manual.
General information
R Only install an approved trailer coupling on
your vehicle.
Further information on availability and on
installation is available from any authorized
Mercedes-Benz Center.
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 To reduce the risk of damage to the ball
coupling, remove it from the ball coupling
recess when not in use.
Coupling up a trailer
GWARNING
While you are coupling or decoupling a trailer,
make sure nobody locks or unlocks the
vehicle and/or opens or closes doors or the
tailgate.
The vehicle's level could change and you
could endanger yourself and/or others as a
result.
Make sure that you do not operate the ADS
button or the vehicle level control system
when coupling/decoupling the trailer.
Observe the maximum permissible trailer
dimensions (width and length).
Most federal states and all Canadian
provinces require by law:
R safety chains between the towing vehicle
and the trailer. The chains should be cross-
wound under the trailer drawbar. They must
be fastened to the vehicle's trailer
coupling, not to the bumper or the axle.
210Trailer towingDriving and parking

Allow for enough play in the chains to
facilitate turning tight corners.
R a separate brake system for certain types
of trailer.
R a safety switch for braked trailers. Check
the specific legal requirements applicable
to your federal state.
If the trailer detaches from the towing
vehicle, the safety switch applies the
trailer's brakes.
! Do not connect the trailer's brake system
(if featured) to the hydraulic brake system
of the towing vehicle, as the latter is
equipped with an anti-lock brake system.
Doing so will result in a loss of function of
the brake systems of both the vehicle and
the trailer.
i The vehicle's wiring harness features a
line to the brake indicator lamp.XMake sure that the automatic transmission
is set to position P.XApply the vehicle's parking brake.XStart the engine.XSelect highway level.XVehicles with the adaptive damping
system: set ADS to AUTO or COMF .XSwitch off the engine.XClose all doors and the tailgate.XCouple up the trailer.XEstablish all electrical connections.
i
Vehicles with the AIRMATIC package:
with a trailer attached, the vehicle will
always remain at highway level. When
coupling up a trailer, please observe the
following:
R if highway level has not been set
manually, the vehicle will automatically
sink to highway level as soon as it
reaches a speed of 5 mph (8 km/h).
R high-speed level is not available.
These restrictions apply to all accessories
powered through a connection to the trailer
power socket of your vehicle, e.g. a bicycle
carrier.
Towing a trailer
There are numerous legal requirements
concerning the towing of a trailer, e.g. speed
restrictions. Make sure that your vehicle/
trailer combination complies with the local
requirements not only in your area of
residence but also at any location to which
you are traveling. The police and local
authorities can provide reliable information.
Please observe the following when towing a
trailer:
R To acquaint yourself with driving with a
trailer and with the resulting changes to
handling, you should practice cornering,
stopping and reversing in a traffic-free
location.
R Before driving, check:
- the trailer tow hitch
- the safety switch for braked trailers
- the safety chains
- the electrical connections
- the lights
- the wheels
R Adjust the exterior mirrors to provide an
unobstructed view of the rear section of the
trailer.
R If the trailer features electronically
controlled brakes, pull away the vehicle/
trailer combination carefully, manually
brake using the brake controller, and check
the brakes for correct function.
R Secure any objects on the trailer to prevent
the cargo from slipping when the vehicle is
in motion.
R If you couple up a trailer, regularly check
the cargo for secure fastening and make
sure that the trailer lamps and (if
applicable) the trailer brakes are
functioning correctly.
R Bear in mind that the handling will be less
stable when towing a trailer than when
Trailer towing211Driving and parkingZ

driving 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, avoid abrupt braking. Depress
the brake pedal moderately at first, so that
the trailer can activate its own brakes. Then
increase the pressure on the brake pedal.
R If the automatic transmission continues to
shift back and forth between two gears
when driving up or downhill, restrict the
shift range. Select shift range 4, 3, 2, or 1.
A lower gear and lower speed reduce the
risk of engine failure.
R On long and steep gradients that are
difficult to drive down in shift range 1,
switch to the off-road drive program or
engage the LOW RANGE off-road gear.
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
dramatically while the air-conditioning
system is switched on, switch off the air-
conditioning system.
Coolant heat can additionally be dissipated
by opening the windows and by setting the
blower fan and the interior temperature to
maximum.
R When overtaking, pay particular attention
to the extended length of your vehicle/
trailer combination.
Due to the length of your vehicle/trailer
combination, you will have to travel an
additional distance beyond the vehicle you
are overtaking before returning to the
previous lane.Decoupling a trailerGWARNING
While you are coupling or decoupling a trailer,
make sure nobody locks or unlocks the
vehicle and/or opens or closes doors or the
tailgate.
The vehicle's level could change and you
could endanger yourself and/or others as a
result.
Make sure that you do not operate the ADS
button or the vehicle level control system
when coupling/decoupling the trailer.
XMake sure that the automatic transmission
is set to position P.XApply the vehicle's parking brake.XStart the engine.XClose all doors and the tailgate.XApply the trailer's parking brake.GWARNING
As soon as you disconnect the electrical
connection between the trailer and the
vehicle, the vehicle will lower. To help avoid
personal injury, make sure no one is near the
wheel housing or underneath the vehicle
before the electrical connection is
disconnected.
When you decouple the trailer, the vehicle is
temporarily raised because the springs are
relieved of load. Be especially careful during
this process, as you could otherwise injure
yourself and/or others. Make sure that any
persons remaining in the vehicle do not press
the switches for vehicle level control or the
ADS.
XRemove the trailer cable and decouple the
trailer.XSwitch off the engine.212Trailer towingDriving and parking

Useful information
i This Operator's Manual describes all
models and all standard and optional
equipment of your vehicle available at the
time of publication of the Operator's
Manual. Country-specific differences are
possible. Please note that your vehicle may
not be equipped with all features
described. This also applies to safety-
related systems and functions.
i Please read the information on qualified
specialist workshops ( Y page 24).
Important safety notes
You will find an illustration of the instrument
cluster in the "At a glance" section
( Y page 29).
GWARNING
A driver's attention to the road and traffic
conditions must always be his/her primary
focus when driving.
For your safety and the safety of others,
selecting features through the multifunction
steering wheel should only be done by the
driver when traffic and road conditions permit
it to be done safely.
Bear in mind that at a speed of just 30 mph
(approximately 50 km/h ), your vehicle is
covering a distance of 44 feet (approximately
14 m) every second.
GWARNING
No messages will be displayed if either the
instrument cluster or the multifunction
display is inoperative.
As a result, you will not be able to see
information about your driving conditions,
such as
R speed
R outside temperature
R warning/indicator lamps
Rmalfunction/warning messages
R failure of any systems
Driving characteristics may be impaired.
If you must continue to drive, do so with added
caution. Contact an authorized Mercedes-
Benz Center as soon as possible.GWARNING
Malfunction and warning messages are only
indicated for certain systems and are
intentionally not very detailed. The
malfunction and warning messages are
simply a reminder with respect to the
operation of certain systems. They do not
replace the owner's and/or driver's
responsibility to maintain the vehicle's
operating safety. Have all required
maintenance and safety checks performed on
the vehicle. Bring the vehicle to an authorized
Mercedes-Benz Center to address the
malfunction and warning messages.
Displays and operation
Tachometer
The red band in the tachometer indicates the
engine's overrevving range.
! Do not drive in the overrevving range, as
this could damage the engine.
The fuel supply is interrupted to protect the
engine when the red band is reached.
Outside temperature display
The outside temperature display is in the
multifunction display ( Y page 218).
GWARNING
The outside temperature indicator is not
designed to serve as an ice-warning device
and is therefore unsuitable for that purpose.
Indicated temperatures just above the
freezing point do not guarantee that the road
216Displays and operationOn-board computer and displays