2012 MERCEDES-BENZ GLK-Class brake

GWARNING
Never depress the brake pedal continuously
while the vehicle is in motion, e.g. never cause
the brakes to rub by applying constant slight
pedal pressure. This causes the brake system
to overheat, increases the braking distance
and can lead to the brakes failing completely.
GWARNING
Under no circumstances try to straighten the
vehicle/trailer combination by increasing the
speed.
General information
R Do not exceed the legally prescribed
maximum 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.
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.
i When towing a trailer, set the tire
pressure on the rear axle of the towing
vehicle for a maximum load; see the tire
pressure table in the fuel filler flap
( Y page 291).
You will find installation dimensions and loads
in the "Technical data" section
( Y page 308).
The maximum noseweight of the trailer
drawbar on the ball coupling is 20
. However,
the actual noseweight must not exceed the
value given on the trailer tow hitch or trailer
identification plates. The lowest weight
applies.
! Use a drawbar noseweight as close as
possible to the maximum permissible
noseweight. Do not use a noseweight that
is under the minimum permissible
noseweight; the trailer may otherwise
come loose. Missing values were not
available at time of going to print.
Note that the payload and the rear axle load
are reduced by the actual payload.
Please note that when towing a trailer,
PARKTRONIC ( Y page 154) is only available
with limitations, or not at all.
i 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.
Driving tips
i Observe the notes on ESP ®
trailer
stabilization ( Y page 64).
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 permitted speed is. Observe the
legally prescribed maximum speed in the
relevant country.
For certain Mercedes-Benz vehicles, the
maximum permissible rear axle load is
increased when towing a trailer. Refer to the
"Technical data" section to find out whether
this applies to your vehicle. 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 permissible
20 Missing values unavailable at time of going to print.160Trailer towingDriving and parking

maximum speed for vehicle/trailer
combinations is above 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.
On long and steep downhill gradients, you
must select shift range 1, 2 or 3 in good time.
i This also applies if you have activated
cruise control.
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 system 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
R Maintain a greater distance from the
vehicle 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, decrease with
increasing altitude.
If the trailer swings from side to side:
XDo not accelerate.XDo not counter-steer.XBrake if necessary.
Installing the ball coupling
GWARNING
If the vehicle/trailer combination is not
secured, the trailer may come loose. As a
result, you could cause an accident.
Observe the ball coupling manufacturer's
installation instructions and special
instructions for use.
! Mercedes-Benz recommends that you
only use ball couplings that have been
tested and approved by Mercedes-Benz.
This helps to avoid damage to the vehicle.
Protective cap
XPull protective cap : in the direction of the
arrow out of ball coupling recess ;.XStow protective cap : safely.XObserve the manufacturer's installation
instructions.GWARNING
If the ball coupling is not correctly installed
and secured, the ball coupling and the trailer
could come loose. As a result, you could
cause an accident.
Therefore, please observe the following:
R Ensure that the ball coupling is secured
according to the ball coupling
manufacturer's installation instructions.
R If the ball coupling cannot be installed as
prescribed, detach the ball coupling. Under
these circumstances, the ball coupling
must not be used for trailer towing.
Have the entire trailer tow hitch checked at a
qualified specialist workshop.
Trailer towing161Driving and parkingZ

Coupling up a trailer
Observe the maximum permissible trailer
dimensions (width and length).
Most U.S. 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.
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 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
connection to the brake indicator lamp.XMake sure that the automatic transmission
is set to position P.XApply the vehicle's parking brake.XClose all doors and the tailgate.XCouple up the trailer.XEstablish all electrical connections.
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
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.162Trailer towingDriving and parking

RIf 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 program or engage
the LOW GEAR 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 trailer
GWARNING
Do not disconnect a trailer with an engaged
overrun brake. Otherwise, your hand could
become trapped between the bumper and
trailer drawbar.
! Do not disconnect a trailer with an
engaged overrun brake. Otherwise, your
vehicle could be damaged by the
rebounding of the overrun brake.XMake sure that the automatic transmission
is set to position P.XApply the vehicle's parking brake.XClose all doors and the tailgate.XApply the trailer's parking brake.XRemove the trailer cable and decouple the
trailer.
Permissible trailer loads and drawbar
noseweights
Weight specifications
The gross trailer weight is calculated by
adding the weight of the trailer to the weight
of the load and equipment on the trailer.
Permissible gross weight: 3500 lbs (1588 kg).
The permissible Trailer drawbar Weight
Rating is the maximum weight permitted on
the trailer drawbar: 21
Limit for Mercedes-
Benz-approved trailer couplings.
Loading a trailer
R When loading the trailer, make sure that
neither the permissible gross weight of the
trailer nor the gross vehicle weight are
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
values on the type plates of your vehicle
and the trailer. Always observe the lowest
respective value when determining the
maximum weight with which you can load
the vehicle and the trailer.
R The trailer drawbar load on the ball coupling
must be added to the rear axle load to avoid
exceeding the permissible gross axle
21 Missing values were not available at time of going to print.Trailer towing163Driving and parkingZ

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 loading the
trailer so that the drawbar noseweight
remains between 8% and 15% of the
permissible gross trailer weight.
i The weight of additional accessories,
passengers, and cargo reduces the
permissible trailer load and drawbar
noseweight 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
maximum permissible values, have the
vehicle/trailer combination (including the
driver, passengers, and cargo with a fully
laden trailer) weighed on a calibrated
weighbridge.
R Check the gross axle weight rating of the
front and rear axles, the gross weight of the
trailer and trailer drawbar noseweight.
Removing the ball coupling
XObserve the manufacturer's installation
instructions.XPress the protective cap into the ball
coupling recess.XMake sure that the protective cap is firmly
in place.
Storing the ball coupling
GWARNING
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:
R brake sharply
R change direction suddenly
R are involved in an accidentXObserve the manufacturer's installation
instructions.
Trailer power supply
The trailer socket of your vehicle is equipped
at the factory with a permanent power supply.
The permanent power supply is supplied via
trailer socket pin 4.
! You can connect accessories with a
maximum power consumption of 240 W to
the permanent power supply.
You must not charge a trailer battery using
the power supply.
The trailer's permanent power supply is
switched off in the event of low vehicle supply
voltage and after six hours at the latest.
You can obtain further information about
installing the trailer's electrical equipment
from a qualified specialist workshop, e.g. an
authorized Mercedes-Benz Center.
164Trailer towingDriving and parking

Safety systemsDisplay messagesPossible causes/consequences and M Solutions!÷
Currently
Unavailable See
Operator's ManualGRisk of accident
ABS (Anti-lock Braking System), ESP ®
(Electronic Stability
Program), BAS (Brake Assist), hill start assist and ESP ®
trailer
stabilization are temporarily unavailable.
In addition, the ä, å and ! warning lamps light up in
the instrument cluster.
The self-diagnosis function might not be complete, for example.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
XCarefully drive a suitable distance making slight steering
movements at a speed above 12 mph (20 km/h).
If the display message disappears, the functions mentioned
above are available again.
If the display message continues to be displayed:
XDrive on carefully.XVisit a qualified specialist workshop.GRisk of accident
ABS, ESP ®
, BAS, hill start assist and ESP ®
trailer stabilization are
temporarily unavailable.
In addition, the ä, å and ! warning lamps light up in
the instrument cluster.
For example, the on-board voltage may be insufficient.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
XDrive on carefully.
If the display message disappears, the functions mentioned
above are available again.
If the display message continues to be displayed:
XDrive on carefully.XVisit a qualified specialist workshop.180Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M Solutions!÷
Inoperative See
Operator's ManualGRisk of accident
ABS, ESP ®
, BAS, hill start assist and ESP ®
trailer stabilization are
unavailable due to a malfunction.
The $ (USA only)/ J (Canada only), ä, å
and ! warning lamps in the instrument cluster also light up.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
XDrive on carefully.XVisit a qualified specialist workshop immediately.÷
Currently
Unavailable See
Operator's ManualGRisk of accident
ESP ®
, BAS, hill start assist and ESP ®
trailer stabilization are
temporarily unavailable.
In addition, the ä and å warning lamps light up in the
instrument cluster.
The self-diagnosis function might not be complete, for example.
The brake system continues to function normally, but without the
functions listed above.
XCarefully drive a suitable distance making slight steering
movements at a speed above 12 mph (20 km/h).
If the display message disappears, the functions mentioned
above are available again.
If the display message continues to be displayed:
XDrive on carefully.XVisit a qualified specialist workshop.GRisk of accident
If the display message is shown and the ä warning lamp flashes
at the same time, the Electronic Traction System is deactivated.
Otherwise, the brakes on the drive wheels could overheat.
XLet the brakes cool down until the display message disappears
and the ä warning lamp goes out.
The Electronic Traction System is activated again.Display messages181On-board computer and displaysZ

Display messagesPossible causes/consequences and M Solutions÷
Inoperative See
Operator's ManualGRisk of accident
ESP ®
, hill start assist and ESP ®
trailer stabilization are unavailable
due to a malfunction.
In addition, the ä and å warning lamps light up in the
instrument cluster.
The brake system continues to function normally, but without the
functions listed above.
XDrive on carefully.XVisit a qualified specialist workshop.T !
÷
Inoperative See
Operator's ManualGRisk of accident
EBD (electronic brake force distribution), ABS, ESP ®
, BAS and hill
start assist are unavailable due to a malfunction.
In addition, the ä, å and ! warning lamps light up in
the instrument cluster and a warning tone sounds.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
XDrive on carefully.XVisit a qualified specialist workshop immediately.#
Check Brake Pad
WearThe brake pads/linings have reached their wear limit.XVisit a qualified specialist workshop.182Display messagesOn-board computer and displays