2014 MERCEDES-BENZ GLK-CLASS SUV ECU

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
compartment, 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.
! If DISTRONIC PLUS or the HOLD function
is activated, the vehicle brakes
automatically in certain situations. To
prevent damage to the vehicle, deactivate
DISTRONIC PLUS and the HOLD function in
the following or other similar situations:
R when towing the vehicle
R in the car wash
Deactivating 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
automatically switched off by the ECO
start/stop function
R the driver's door is closed or your seat belt
is fastened
R the parking brake is released
R the hood is closed.
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 ë appears 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 accelerate and the transmission is in
position Dor R.
R the transmission is in position P.
R you depress the brake pedal again with a
certain amount of pressure until ë
disappears from the multifunction display.
R you activate DISTRONIC PLUS.
When the HOLD function is activated in
vehicles with an automatic transmission, the
transmission is shifted automatically to
position P 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
automatically switched off by the ECO
start/stop function.
R the hood is opened.
R a system malfunction occurs.
R the power supply is not sufficient.
The horn will also sound at regular intervals if
the HOLD function is activated and you:
R switch the engine off, open the driver's
door and remove your seat belt.
R open the hood.
The sounding of the horn alerts you to the fact
that the vehicle has been parked while the 184
Driving systemsDriving and pa
rking

climbing capability, decreases with
increasing altitude.
If the trailer swings from side to side:
X Do not accelerate.
X Do not counter-steer.
X Brake if necessary. Installing the ball coupling
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
described in the ball coupling installation
instructions. Make sure that the ball coupling
is installed and secured correctly before every
journey.
! 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. Cover cap
X
Pull protective cap :in the direction of the
arrow, out of ball coupling recess ;.
X Store protective cap :in a safe place.
X Observe the manufacturer's installation
instructions. G
WARNING
If the ball coupling is not installed and secured
correctly it can become detached while the vehicle is in motion and fall onto the road.
There is a risk of an accident and injury.
Install and secure the ball coupling as
described in the ball coupling installation
instructions. Make sure that the ball coupling
is installed and secured correctly before every
journey.
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.
Leave enough play in the chains to make
tight cornering possible.
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.
X Make sure that the automatic transmission
is set to position P.
X Apply the vehicle's parking brake.
X Close all doors and the tailgate. 214
Towing a trailerDriving and parking

X
Couple up the trailer.
X Establish 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 car/trailer
combination complies with the local
regulations:
R in your place of residence
R in the location to which you are driving
The police and local authorities can provide
reliable information.
Observe the following when towing a trailer:
R To gain driving experience and to become
accustomed to the new handling
characteristics, you should practice the
following in a traffic-free location:
- cornering
- stopping
- backing up
R Before driving, check:
-the trailer tow hitch
- the safety switch for braked trailers
- the safety chains
- 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 has electronically controlled
brakes, pull away carefully. Brake manually
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
regular 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
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 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
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 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. Towing a trailer
215Driving and parking Z

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:
R brake sharply
R change direction suddenly
R are involved in an accident
X Observe 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 Wto
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.
A qualified specialist workshop can provide
more information about installing the trailer
electrics. Towing a trailer
217Driving and parking Z

Display messages Possible causes/consequences and
M
MSolutions $(USA
only)
J(Canada
only)
Check Brake Fluid Check Brake Fluid
Level Level There is not enough brake fluid in the brake fluid reservoir.
In addition, the
$(USA only)/ J(Canada only) warning
lamp lights up in the instrument cluster and a warning tone
sounds.
G WARNING
The braking effect may be impaired.
There is a risk of an accident.
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions. Do not continue driving
under any circumstances.
X Secure the vehicle against rolling away ( Ypage 164).
X Consult a qualified specialist workshop.
X Do not add brake fluid. This does not correct the malfunction. #
Check Brake Pad Check Brake Pad
Wear Wear The brake pads/linings have reached their wear limit.
X
Visit a qualified specialist workshop. G
Inoperative Inoperative One or more main features of the mbrace system are
malfunctioning.
X
Have the mbrace system checked immediately at a qualified
specialist workshop. PRE-SAFE PRE-SAFE
Inoperative See Inoperative See
Operator's Manual Operator's Manual
Important functions of PRE-SAFE
®
have failed. All other occupant
safety systems, e.g. air bags, remain available.
X Visit a qualified specialist workshop immediately. 238
Display
messagesOn-board computer and displays

Display messages Possible causes/consequences and
M
MSolutions PRE-SAFE
PRE-SAFE
Functions Functions
Currently Limited Currently Limited
See Operator's See Operator's
Manual Manual
PRE-SAFE
®
Brake is temporarily inoperative. Possible causes are:
R function is impaired due to heavy rain or snow.
R the sensors in the radiator grill and the bumper are dirty.
R the radar sensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio
stations or other sources of electromagnetic radiation.
R the system is outside the operating temperature range.
R the on-board voltage is too low.
When the causes stated above no longer apply, the display
message disappears.
PRE-SAFE ®
Brake is operational again.
If the display message does not disappear:
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away ( Ypage 164).
X Clean the sensors in the radiator grill and the bumper
(Y page 309).
X Restart the engine. PRE-SAFE PRE-SAFE
Functions Limited Functions Limited
See Operator's See Operator's
Manual Manual
PRE-SAFE
®
Brake is inoperative due to a malfunction. BAS PLUS
or the distance warning signal may also have failed.
X Visit a qualified specialist workshop. 6
SRS Malfunction SRS Malfunction
Service Required Service Required There is a malfunction in the SRS (Supplemental Restraint
System). The
6warning lamp also lights up in the instrument
cluster.
G WARNING
The air bags or Emergency Tensioning Devices may either be
triggered unintentionally or, in the event of an accident, may not
be triggered.
There is an increased risk of injury.
X Visit a qualified specialist workshop.
For further information about SRS, see (Y page 43). Display
messages
239On-board computer and displays Z

Display messages Possible causes/consequences and
M
MSolutions Front Passenger
Front Passenger
Airbag Disabled Airbag Disabled
See Operator's See Operator's
Manual Manual The front-passenger air bag is disabled during the journey, even
though:
R
an adult
or
R a person larger than a certain size is occupying the front-
passenger seat
If additional forces are applied to the seat, the system may
interpret the occupant's weight as lower than it actually is.
G WARNING
The front-passenger air bag does not deploy during an accident.
There is an increased risk of injury.
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away ( Ypage 164).
X Switch the ignition off.
X Have the occupant get out of the vehicle.
X Keep the seat unoccupied, close the front-passenger door and
switch on the ignition.
X Observe the PASSENGER AIR BAG OFF indicator lamp in the
center console and the multifunction display and check the
following:
Seat unoccupied and ignition switched on:
R the PASSENGER AIR BAG OFF indicator lamp must light up and
remain lit. If the indicator lamp is on, OCS has disabled the front-
passenger air bag ( Ypage 49).
R the Front Passenger Airbag Enabled See Operator's
Front Passenger Airbag Enabled See Operator's
Manual Manual orFront Passenger Airbag Disabled See
Front Passenger Airbag Disabled See
Operator's Manual
Operator's Manual display messages must not be shown in
the multifunction display.
X Wait for a period of at least 60 seconds until the necessary
system checks have been completed.
X Make sure that the display messages do not appear in the
multifunction display.
If these conditions are fulfilled, the front-passenger seat can be
occupied again. Whether the PASSENGER AIR BAG OFF indicator
lamp remains lit or goes out depends on how OCS classifies the
occupant.
If the conditions are not fulfilled, the system is not operating
correctly.
X Visit a qualified specialist workshop immediately. Display
messages
241On-board computer and displays Z

Display messages Possible causes/consequences and
M
MSolutions For further information about the Occupant Classification System,
see (Y
page 49). Front Passenger Front Passenger
Airbag Enabled Airbag Enabled
See Operator's See Operator's
Manual Manual The front-passenger air bag is enabled during the journey, even
though:
R
a child, a small adult or an object weighing less than the
system's weight threshold is located on the front-passenger
seat
or
R the front-passenger seat is unoccupied
The system may detect objects or forces applying additional
weight on the seat.
G WARNING
The air bag may deploy unintentionally.
There is an increased risk of injury.
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away ( Ypage 164).
X Switch the ignition off.
X Open the front-passenger door.
X Remove the child and the child restraint system from the front-
passenger seat.
X Make sure that there are no objects on the seat adding to the
weight.
The system may otherwise detect the additional weight and
interpret the seat occupant's weight as greater than it actually
is.
X Keep the seat unoccupied, close the front-passenger door and
switch on the ignition.
X Observe the PASSENGER AIR BAG OFF indicator lamp in the
center console and the multifunction display and check the
following:
Seat unoccupied and ignition switched on:
R the PASSENGER AIR BAG OFF indicator lamp must light up and
remain lit. If the indicator lamp is on, OCS (Occupant
Classification System) has disabled the front-passenger air bag
(Y page 49).
R the Front Passenger Airbag Enabled See Operator's Front Passenger Airbag Enabled See Operator's
Manual Manual orFront Passenger Airbag Disabled See
Front Passenger Airbag Disabled See
Operator's Manual
Operator's Manual display messages must not be shown in
the multifunction display. 242
Display
messagesOn-board computer and displays