2013 MERCEDES-BENZ GLA SUV ECU

(grease free), depending on the instruc-
tions for the trailer.
Coupling up a trailer
X Make sure that the transmission is in posi-
tion P.
X Apply the electric parking brake.
X Position the trailer level behind the vehicle.
X Couple up the trailer.
X Establish the electric connection between
the vehicle and the trailer.
X Check that the trailer lighting system is
working.
A trailer that is connected is recognised
only when the electrical connection is
established correctly and when the lighting system is working properly. The function of
other systems, such as ESP ®
or PARK-
TRONIC also depends on this. Uncoupling a trailer
G
WARNING
If you uncouple a trailer with an engaged over- run brake, you could trap your hand between
the vehicle and the trailer drawbar. This poses a risk of injury.
Do not uncouple a trailer with an engaged
overrun brake.
! Do not disconnect a trailer with an
engaged overrun brake. Otherwise, your
vehicle could be damaged by the rebound- ing of the overrun brake.
! Remove the installed adapter cable
before folding in the ball coupling. Other-
wise, damage may occur to the rear
bumper and the adapter cable.
X Make sure that the transmission is in posi-
tion P.
X Apply the electric parking brake. X
Secure the trailer against rolling away.
X Remove the trailer cable and decouple the
trailer. Folding in the ball coupling
G
WARNING
If you release the ball coupling or it does not
engage correctly when folding in, it will swing out. Within pivoting range of the ball coupling,
there is an increased risk of an accident and
injury.
Only release the ball coupling if the pivoting
range is unobstructed. Always make sure that the ball coupling engages when folding in.
X Fold the ball coupling back in if you are not
using the trailer tow hitch.
X Place the protective covering on the ball
coupling.
The release wheel is located behind the left-
hand side trim panel in the boot. X
To open the cover: turn handle:anti-
clockwise and fold down cover ;and
remove it. Towing a trailer
229Driving and parking Z

Fitting the adapter
!
Make sure that there is sufficient cable
play so that the cable cannot become
detached when cornering.
! Remove the installed adapter cable
before folding in the ball coupling. Other-
wise, damage may occur to the rear
bumper and the adapter cable. X
Open the socket cover.
X Insert the plug connector with lug :into
groove =on the socket. Turn bayonet con-
nection ;clockwise to the stop.
X Let the cover engage.
X If you are using an adapter cable, secure
the cable to the trailer with cable ties. Towing a trailer
231Driving and parking Z

Display messages
Possible causes/consequences and
M
MSolutions The red
!indicator lamp flashes and the yellow !warning
lamp is lit.
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 !indicator lamp continues to flash:
X Do not drive on.
X Secure the vehicle against rolling away (Y page 363).
X Vehicles with manual transmission: engage first gear.
X Vehicles with automatic transmission: shift the transmission
to P.
X Turn the front wheels towards the kerb.
X Consult a qualified specialist workshop. The yellow
!warning lamp lights up. The red !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 apply the electric parking brake:
X Vehicles with manual transmission: engage first gear.
X Vehicles with automatic transmission: shift the transmission
to P.
X Visit a qualified specialist workshop.
If it is not possible to release the electric parking brake:
X Vehicles with manual transmission (automatic emergency
release): insert the seat belt in the belt buckle and accelerate
slightly more when pulling away.
X Vehicles with automatic transmission: release the electric
parking brake automatically (Y page 180).
If the electric parking brake still cannot be released:
X Consult a qualified specialist workshop. Display
messages
259On-board computer and displays Z

Display messages
Possible causes/consequences and
M
MSolutions J
Brake immediately Brake immediately Vehicles with manual transmission: a malfunction has occurred
while the HOLD function was activated.
A tone may also sound at regular intervals. If you attempt to lock the vehicle, the tone becomes louder.
You cannot start the engine.
X Paying attention to the traffic situation, immediately depress the
brake pedal firmly and hold until the display message disap-
pears.
X Secure the vehicle against rolling away (Y page 179).
You can restart the engine. J
Check brake fluid Check brake fluid
level level There is insufficient brake fluid in the brake fluid reservoir.
In addition, the red Jwarning lamp lights up in the instrument
cluster and a warning tone sounds.
G WARNING
Braking efficiency 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 (Y page 179).
X Consult a qualified specialist workshop.
X Do not top up the brake fluid. This does not correct the fault. #
Check brake pad Check brake pad
wear wear The brake pads/linings have reached their wear limit.
X Visit a qualified specialist workshop. Display
messages
261On-board computer and displays Z

Display messages
Possible causes/consequences and
M
MSolutions Collision Preven‐
Collision Preven‐
tion Assist Plus tion Assist Plus
currently unavail‐ currently unavail‐
able See Owner's able See Owner's
Manual Manual COLLISION PREVENTION ASSIST PLUS is temporarily inoperative.
Possible causes:
R the front bumper is dirty
R the function is impaired due to heavy rain or snow
R the radar sensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio sta-
tions or other sources of electromagnetic radiation
R AMG vehicles: ESP ®
is deactivated
R the system is outside the operating temperature range
R The on-board voltage is too low.
Once the causes listed above no longer apply, the display message goes out.
COLLISION PREVENTION ASSIST PLUS 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 (Y page 179).
X Clean the front bumper (Y page 326).
X Restart the engine.
X AMG vehicles: reactivate ESP ®
(Y page 78). Collision Preven‐ Collision Preven‐
tion Assist Plus tion Assist Plus
inoperative
inoperative COLLISION PREVENTION ASSIST PLUS is malfunctioning. The dis-
tance warning signal may also have failed.
X Visit a qualified specialist workshop. 262
Display
messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions PRE-SAFE
PRE-SAFE
Functions cur‐ Functions cur‐
rently rently
limited
limited See
See
Owner's Manual
Owner's Manual Adaptive Brake Assist is temporarily inoperative. Possible causes:
R the front bumper is dirty
R the function is impaired due to heavy rain or snow
R the radar sensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio sta-
tions or other sources of electromagnetic radiation
R AMG vehicles: ESP ®
is deactivated
R the system is outside the operating temperature range
R the on-board voltage is too low.
Once the causes listed above no longer apply, the display message goes out.
Adaptive Brake Assist 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 (Y page 179).
X Clean the front bumper (Y page 326).
X Restart the engine.
X AMG vehicles: reactivate ESP ®
(Y page 78). PRE-SAFE PRE-SAFE
Functions limited Functions limited
See Owner's Manual See Owner's Manual Adaptive Brake Assist is faulty. The distance warning signal may
also have failed.
X Visit a qualified specialist workshop. PRE-SAFE PRE-SAFE
inoperative See inoperative See
Owner's Manual Owner's Manual
Important functions of PRE-SAFE
®
have failed. All other occupant
safety systems, e.g. airbags, remain available.
X Visit a qualified specialist workshop immediately. ü If this symbol appears in the multifunction display, a seat belt
tongue has been inserted into a rear seat belt buckle.
Further information on the status indicator for the rear seat belts
(Y page 48). Display
messages
263On-board computer and displays Z

Display messages
Possible causes/consequences and
M
MSolutions Front-passenger
Front-passenger
airbag disabled airbag disabled
See Owner's Manual See Owner's Manual The front-passenger front airbag is disabled during the journey
although:
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 weight the system
detects may be too low.
G WARNING
The front-passenger front airbag does not deploy during an acci-
dent.
This poses 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 to prevent it from rolling away (Y page 179).
X Switch the ignition off.
X Have the occupant on the front-passenger seat step out of the
vehicle.
X Make sure that the seat is unoccupied, close the front-
passenger door and switch on the ignition.
X Observe the PASSENGER AIRBAG indicator lamps in the centre
console and the multifunction display and check the following:
Seat unoccupied and ignition switched on: R the PASSENGER AIR BAG OFF and PASSENGER AIR BAG ON
indicator lamps must light up simultaneously for approximately
six seconds.
R the PASSENGER AIRBAG OFF indicator lamp must then light up
and remain lit. If the indicator lamp is on, the automatic front-
passenger front airbag deactivation system has disabled the
front-passenger front airbag (Y page 52).
R the Front-passenger airbag enabled See Owner's Man‐
Front-passenger airbag enabled See Owner's Man‐
ual ual orFront-passenger airbag disabled See Owner's
Front-passenger airbag disabled See Owner's
Manual
Manual display messages must not be shown in the multifunc-
tion display.
X Wait for a period of at least 60 seconds until the necessary sys-
tem checks have been completed.
X Make sure that the display messages do not appear in the mul-
tifunction display.
If these conditions are met, the front-passenger seat can be occu-
pied again. Whether the PASSENGER AIRBAG OFF or ON indicator
lamp remains lit or goes out depends on how the automatic front- 266
Display
messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions passenger front airbag deactivation system classifies the occu-
pant.
If the conditions are not met, the system is not operating correctly.
X Visit a qualified specialist workshop immediately.
For further information on the automatic front-passenger front
airbag deactivation feature, see (Y page 51).Front-passenger Front-passenger
airbag airbag
enabled
enabled See
See
Owner's Manual
Owner's Manual The front-passenger front airbag is enabled during the journey
although:
R a child, a small adult or an object weighing less than the system
weight threshold is located on the front-passenger seat
or
R the front-passenger seat is not occupied
The automatic front-passenger front airbag deactivation system
may detect objects or forces that are adding to the weight applied to the seat.
G WARNING
The airbag may deploy unintentionally.
This poses 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 to prevent it from rolling away (Y page 179).
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 there are no objects applying additional force to the
seat.
The system may otherwise detect the additional force and inter-
pret the seat occupant's weight as greater than it actually is.
X Make sure that the seat is unoccupied, close the front-
passenger door and switch on the ignition.
X Observe the PASSENGER AIRBAG indicator lamps in the centre
console and the multifunction display and check the following:
Seat unoccupied and ignition switched on: R the PASSENGER AIR BAG OFF and PASSENGER AIR BAG ON
indicator lamps must light up simultaneously for approximately
six seconds.
R the PASSENGER AIRBAG OFF indicator lamp must then light up
and remain lit. If the indicator lamp is on, the automatic front- Display
messages
267On-board computer and displays Z