2016 MERCEDES-BENZ GL check engine light

so will result in a loss of function of the
brake systems of both the vehicle and the
trailer. X
Shift the transmission to position P .X
Apply the vehicle's electric parking brake. X
Start the engine. X
Vehicles with the AIRMATIC package:
select highway level. X
Vehicles with ADS: set ADS to AUTO or
COMF .X
Switch off the engine. X
Close the doors and tailgate. X
Couple up the trailer. X
Establish the electrical connection
between the vehicle and the trailer. X
Check that the trailer lighting system is
working.
i Vehicles with the AIRMATIC package:
with a trailer attached, the vehicle will
always remain at highway level. When cou-
pling up a trailer, please observe the fol-
lowing: R
Unless highway level has been set man-
ually, the vehicle is automatically low-
ered to highway level. This is the case if a
speed of 5 mph (8 km/h) is reached. 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.
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 cou-
pling, 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
Safety switch for braked trailers. Check the
specific legal requirements applicable to
your state.
If the trailer becomes detached from the
towing vehicle, the safety switch applies
the trailer brakes.
Towing a trailer There are numerous legal requirements con-
cerning the towing of a trailer, e.g. speed
restrictions. Make sure that your car/trailer
combination complies with the local regula-
tions: 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 charac-
teristics, you should practice the following
in a traffic-free location: -
cornering -
stopping -
backing up R
Before driving, check: -
trailer tow hitch -
safety switch for braked trailers -
safety chains -
electrical connections -
lights -
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 Towing a trailer 267
Driving and parking Z

using the brake controller and check
whether the brakes function correctly. R
Se cure 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 han dlin g will be less
st able when towing a trailer than when driv-
ing wit hout one. Avoid sudden steering
movements. R
The vehicle/trailer combination is heavier,
accelerates more slowly, has a decreased
gradient cli mbin g capability and a longer
braking dist ance.
It is more susceptible to side winds and
requires more careful steering. R
If poss ible, do not brake suddenly, but
instead depr ess the brake pedal moder-
ate ly at first so that the trailer can activate
it s brakes. Then increase the pressure on
the brake pedal. R
If the automat ic transmission repeat edly
shifts between gears on uphill or down hill
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 driv ing down hill, shift to a lower gear
to uti liz e the engine's braking effect.
Avoid continuous brake application as this
m ay
overheat the vehicle brakes and, if
instal led, the trailer brakes.R
If the coolant temperature increases dra-
matical ly while the air-cond it ioning system
is swit ched on, switch off the air-condition-
ing system.
Coolant heat can also be dissipated by
opening the win dows and switching the ventilation blowe r and the interior temper-
ature to the highest leve l.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 WARNIN G
If you uncouple a trailer wit h th e overrun
brak e engaged , you could trap your han d
between th e vehicl e and th e trailer drawbar.
Ther e is a ris k of injury.
Do no t uncouple a trailer if th e overrun brak e
is engaged .
G WARNIN G
Vehicles wit h leve l control :
The vehicl e is lowered as soo n as you discon -
nect th e trailer cable. This could result in your
limb s or those of other people that are
between th e vehicl e body and tires or under-
neath th e vehicl e bein g trapped . Ther e is a
ris k of injury.
Mak e sure that nobody is in th e immediat e
vicinity of th e whee l housing s or under th e
vehicl e when you disconnect th e trailer cable.
! Do not disc onnect a trailer wit h an
engaged overrun brake. Otherwise, your
vehicle could be damaged by the reboun d-
ing of the overrun brake. X
Sh ift the transmission to position P .X
Ap ply the vehicle's electr ic parking brake.X
St art the engine. X
Close the doors and tailgate. X
Apply the trailer's parking brake.268
Towing a trailer
Driving and parking

Problem
Possible causes/consequences and P Solutions
I (USA only)
The red electric parking
brake indicator lamp
flashes or lights up
and/or
$
the yellow warning
lamp for the electric
parking brake lights up. X
Observe the additional display messages in the multifunction
display.
u
The red restraint sys-
tem warning lamp is lit
while the engine is run-
ning. The restraint system is faulty.
G WARNING
The air bags or Emergency Tensioning Devices may either be trig-
gered unintentionally or, in the event of an accident, may not be
triggered.
There is an increased risk of injury. X
Observe the additional display messages in the multifunction
display. X
Drive on carefully. X
Have the restraint system checked immediately at a qualified
specialist workshop.
For further information about the restraint system, see
( Y
page 44).Warning and indicator lamps in the instrument cluster 333
On-board computer and displays Z

! Make sure that the windshield wipers are
not folded away from the windshield. You
could otherwise damage the windshield
wipers or the hood. X
Make sure that the windshield wipers are
turned off. X
Pull release lever C on the hood.
The hood is released.
X
Reach into the gap, pull hood catch han-
dle D up and lift the hood.
If you lift the hood by approximately 15 in
(40 cm), the hood is opened and held open
automatically by the gas-filled strut.
Closing the hood X
Lower the hood and let it fall from a height
of approximately 8 in (20 cm). X
Check that the hood has engaged properly.
If the hood can be raised slightly, it is not
properly engaged. Open it again and close
it with a little more force. Radiator Vehicles with a diesel engine: do not cover
the radiator, for example with a winter front or
bug cover. The readings of the on-board-diag-
nostic system may otherwise be inaccurate.
Some of these readings are required by law
and must be accurate at all times.
Engine oil
General notes Depending on your driving style, the vehicle
consumes up to 0.9 US qt (0.8 liters) of oil per
600 miles (1,000 km). The oil consumption
may be higher than this when the vehicle is
new or if you frequently drive at high engine
speeds.
Depending on the engine, the oil dipstick may
be in a different location.
When checking the oil level: R
park the vehicle on a level surface. R
the engine should be switched off for
approximately five minutes if the engine is
at normal operating temperature. R
if the engine is not at normal operating
temperature, e.g. if the engine was only
started briefly, wait about 30 minutes
before carrying out the measurement.
Checking the oil level using the oil dip-
stick
G WARNING
Certain components in the engine compart-
ment, such as the engine, radiator and parts
of the exhaust system, can become very hot.
Working in the engine compartment poses a
risk of injury.
Where possible, let the engine cool down and
touch only the components described in the
following.Engine compartment 371
Maintenance and care Z

qualified specialist workshop for further infor-
mation.
Have the battery condition of charge checked
more frequently if you use the vehicle mainly
for short trips or if you leave it standing idle
for a lengthy period. Consult a qualified spe-
cialist workshop if you wish to leave your
vehicle parked for a long period of time.
Remove the SmartKey if you park the vehicle
and do not require any electrical consumers.
The vehicle will then use very little energy,
thus conserving battery power.
i If the power supply has been interrupted,
e.g. if you reconnect the battery, you will
have to: R
set the clock. Information on setting the
clock can be found in the Digital Opera-
tor's Manual.
On vehicles with COMAND and a naviga-
tion system, the clock is set automati-
cally. R
reset the function for folding the exterior
mirrors in/out automatically, by folding
the mirrors out once ( Y
page 125).
Charging the battery
G WARNING
During charging and jump-starting, explosive
gases can escape from the battery. There is a
risk of an explosion.
Particularly avoid fire, open flames, creating
sparks and smoking. Ensure there is sufficient
ventilation while charging and jump-starting.
Do not lean over a battery.
G WARNING
Battery acid is caustic. There is a risk of injury.
Avoid contact with skin, eyes or clothing. Do
not inhale any battery gases. Do not lean over
the battery. Keep children away from batter-
ies. Wash away battery acid immediately with
plenty of clean water and seek medical atten-
tion. G WARNING
A discharged battery can freeze at tempera-
tures below freezing point. When jump-start-
ing the vehicle or charging the battery, gases
can escape from the battery. There is a risk of
an explosion.
Allow the frozen battery to thaw out before
charging it or jump-starting.
! Only use battery chargers with a maxi-
mum charging voltage of 14.8 V.
! Only charge the battery using the jump-
starting connection point.
If, at low temperatures, the indicator lamps/
warning lamps in the instrument cluster do
not light up, it is highly likely that the dis-
charged battery has frozen. In this case you
may neither jump-start the vehicle nor charge
the battery. The service life of a thawed-out
battery may be shorter. The starting charac-
teristics can be impaired, particularly at low
temperatures. Have the thawed-out battery
checked at a qualified specialist workshop.
Never charge the battery if it is still installed in
the vehicle, unless you use a battery charger
which has been tested and approved by
Mercedes-Benz. A battery charger unit spe-
cially adapted for Mercedes-Benz vehicles
and tested and approved by Mercedes-Benz
is available as an accessory. It permits the
charging of the battery in its installed posi-
tion. Contact an authorized Mercedes-Benz
Center for further information and availabil-
ity. Charge the battery in accordance with the
separate instructions for the battery charger.
The jump-starting connection point is in the
engine compartment ( Y
page 395).
Read the battery charger's operating instruc-
tions before charging the battery. X
Open the hood. X
Connect the battery charger to the positive
terminal and ground point in the same
order as when connecting the donor bat-
tery in the jump-starting procedure
( Y
page 395).394
Battery (vehicle)
Breakdown assistance

Jump-starting For the jump-starting procedure, use only the jump-starting connection point, consisting of a
positive terminal and a ground point, in the engine compartment.
G WARNING
Battery acid is caustic. There is a risk of injury.
Avoid contact with skin, eyes or clothing. Do not inhale any battery gases. Do not lean over the
battery. Keep children away from batteries. Wash away battery acid immediately with plenty of
clean water and seek medical attention.
G WARNING
During charging and jump-starting, explosive gases can escape from the battery. There is a risk
of an explosion.
Particularly avoid fire, open flames, creating sparks and smoking. Ensure there is sufficient ven-
tilation while charging and jump-starting. Do not lean over a battery.
G WARNING
During the charging process, a battery produces hydrogen gas. If a short circuit occurs or sparks
are created, the hydrogen gas can ignite. There is a risk of an explosion. R
Make sure that the positive terminal of a connected battery does not come into contact with
vehicle parts. R
Never place metal objects or tools on a battery. R
It is important that you observe the described order of the battery terminals when connecting
and disconnecting a battery. R
When jump-starting, make sure that the battery poles with identical polarity are connected. R
It is particularly important to observe the described order when connecting and disconnecting
the jumper cables. R
Never connect or disconnect the battery terminals while the engine is running.
G WARNING
A discharged battery can freeze at temperatures below freezing point. When jump-starting the
vehicle or charging the battery, gases can escape from the battery. There is a risk of an explosion.
Allow the frozen battery to thaw out before charging it or jump-starting.
! Vehicles with a gasoline engine: avoid repeated and lengthy starting attempts. Other-
wise, the catalytic converter could be damaged by non-combusted fuel.
If the indicator/warning lamps do not light up at low temperatures, it is very likely that the
discharged battery has frozen. In this case you may neither jump-start the vehicle nor charge
the battery. The service life of a thawed-out battery may be shorter. The starting characteristics
can be impaired, particularly at low temperatures. Have the thawed-out battery checked at a
qualified specialist workshop. Jump-starting 395
Breakdown assistance Z