2015 MERCEDES-BENZ GL-Class check engine light

Useful information
i This Operator's Manual describes all
models and all standard and optional equip- ment 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 Read the information on qualified special-
ist workshops (Y page 29). Correct driver's seat position
G
WARNING
You could lose control of your vehicle if you do the following while driving:
R adjust the driver's seat, head restraint,
steering wheel or mirrors
R fasten the seat belt
There is a risk of an accident.
Adjust the driver's seat, head restraint, steer-
ing wheel and mirror and fasten your seat belt before starting the engine. X
Observe the safety guidelines on seat
adjustment (Y page 107).
X Make sure that seat 0087is adjusted prop-
erly.
Electrical seat adjustment (Y page 108)
When adjusting the seat, make sure that:
R you are as far away from the driver's air bag
as possible.
R you are sitting in a normal upright position.
R you can fasten the seat belt properly.
R you have moved the backrest to an almost
vertical position.
R you have set the seat cushion angle so that
your thighs are gently supported.
R you can depress the pedals properly.
X Check whether the head restraint is adjus-
ted properly.
When doing so, make sure that you have
adjusted the head restraint so that the back of your head is supported at eye level by the
center of the head restraint. Also make
sure that you have adjusted the head
restraint so that the back of your head is as close to the head restraint as possible. Thiswill be the case if the head restraint is
adjusted correctly (Y page 109).
X Observe the safety guidelines on steering
wheel adjustment (Y page 119).
X Make sure that steering wheel 0043is adjus-
ted properly.
Adjusting the steering wheel manually
(Y page 119)
Adjusting the steering wheel electrically
(Y page 120)
When adjusting the steering wheel, make
sure that:
R you can hold the steering wheel with your
arms slightly bent.
R you can move your legs freely.
R you can see all the displays in the instru-
ment cluster clearly.
X Observe the safety guidelines for seat belts
(Y page 46). 106
Correct driver's seat positionSeats, steering wheel and mirrors

Problems with the seat ventilation
Problem
Possible causes/consequences and
0050
0050Solutions The seat ventilation has
switched off prema-
turely or cannot be
switched on. The on-board voltage is too low because too many electrical con-
sumers are switched on.
X Switch off electrical consumers that you do not need, such as
the rear window defroster or interior lighting.
Once the battery is sufficiently charged, the seat ventilation will
switch back on automatically. Steering wheel
Important safety notes
G
WARNING
You could lose control of your vehicle if you do the following while driving:
R adjust the driver's seat, head restraint,
steering wheel or mirrors
R fasten the seat belt
There is a risk of an accident.
Adjust the driver's seat, head restraint, steer-
ing wheel and mirror and fasten your seat belt before starting the engine. G
WARNING
Children could injure themselves if they
adjust the steering wheel. There is a risk of
injury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never leave children unsupervised in the vehicle. Adjusting the steering wheel man-
ually
G
WARNING
If the steering wheel is unlocked while the
vehicle is in motion, it could change position
unexpectedly. This could cause you to lose
control of the vehicle. There is a risk of an
accident. Before starting off, make sure the steering
wheel is locked. Never unlock the steering
wheel while the vehicle is in motion.
0043
Release lever
0044 To adjust the steering wheel height
0087 To adjust the steering wheel position
(fore-and-aft adjustment)
X Push release lever 0043down completely.
The steering column is unlocked.
X Adjust the steering wheel to the desired
position.
X Push release lever 0043up completely.
The steering column is locked.
X Check if the steering column is locked.
When doing so, try to push the steering
wheel up or down or try to move it in the
fore-and-aft direction. Steering wheel
119Seats, steering wheel and mirrors Z

0083
003D To switch the right-hand front read-
ing lamp on/off
0084 To switch the automatic interior lighting
control on
X To switch the front interior lighting on:
set the switch to the 004Aposition.
X To switch the interior lighting off: set the
switch to the 0033position or (if the door is
closed) to the center position.
X To switch the rear interior lighting on/
off: press the 0042button.
X To switch the reading lamps on/off:
press the 003Dbutton. Crash-responsive emergency lighting
The interior lighting is activated automatically
if the vehicle is involved in an accident.
X To switch off the crash-responsive
emergency lighting: press the hazard
warning lamp button.
or X Lock and then unlock the vehicle using the
SmartKey. Replacing bulbs
Important safety notes
G
DANGER
Xenon bulbs carry a high voltage. You can get an electric shock if you remove the cover of
the Xenon bulb and touch the electrical con-
tacts. There is a risk of fatal injury.
Never touch the parts or the electrical con-
tacts of the Xenon bulb. Always have work on
the Xenon bulbs carried out at a qualified spe-
cialist workshop.
If your vehicle is equipped with Xenon bulbs,
you can recognize this by the following: the
cone of light from the Xenon bulbs moves
from the top to the bottom and back again
when you start the engine. For this to be observed, the lights must be switched on
before starting the engine. G
WARNING
Bulbs, lamps and connectors can get very hot when operating. If you change a bulb, you
could burn yourself on these components.
There is a risk of injury.
Allow these components to cool down before changing a bulb.
Do not use a bulb that has been dropped or if
its glass tube has been scratched.
The bulb may explode if:
R you touch it
R it is hot
R you drop it
R you scratch it
Only operate bulbs in enclosed lamps
designed for that purpose. Only install spare
bulbs of the same type and the specified volt- age.
Marks on the glass tube reduce the service
life of the bulbs. Do not touch the glass tube
with your bare hands. If necessary, clean the
glass tube when cold with alcohol or spirit and
rub it off with a lint-free cloth.
Protect bulbs from moisture during opera-
tion. Do not allow bulbs to come into contact
with liquids.
There are bulbs other than the Xenon bulbs
that you cannot replace. Replace only the
bulbs listed (Y page 138). Have the bulbs that
you cannot replace yourself changed at a
qualified specialist workshop.
If you require assistance changing bulbs, con- sult a qualified specialist workshop.
If the new bulb still does not light up, consult
a qualified specialist workshop.
Bulbs and lamps are an important aspect of
vehicle safety. You must therefore make sure that these function correctly at all times.
Have the headlamp setting checked regularly. Replacing bulbs
137Lights and windshield wipers Z

Problems with the windshield wipers
Problem
Possible causes/consequences and
0050
0050Solutions The windshield wipers
are jammed. Leaves or snow, for example, may be obstructing the windshield
wiper movement. The wiper motor has been deactivated.
X For safety reasons, you should remove the SmartKey from the
ignition lock.
or X Switch off the engine using the Start/Stop button and open the
driver's door.
X Remove the cause of the obstruction.
X Switch the windshield wipers back on. The windshield wipers
fail completely. The windshield wiper drive is malfunctioning.
X Select another wiper speed on the combination switch.
X Have the windshield wipers checked at a qualified specialist
workshop. Windshield wipers
143Lights and windshield wipers Z

the case if you are not depressing the brake
pedal.
If you depress the brake pedal and press the
Start/Stop button, the engine starts immedi-
ately.
A check which periodically establishes a radio
connection between the vehicle and the
SmartKey determines whether a valid Smart- Key is in the vehicle. This occurs, for example, when starting the engine.
To start the vehicle without actively using the
SmartKey:
R the Start/Stop button must be inserted in
the ignition lock.
R the SmartKey must be in the vehicle.
R the vehicle must not be locked with the
SmartKey or KEYLESS-GO (Y page 83).
Do not keep the SmartKey:
R with electronic devices, e.g. a mobile
phone or another SmartKey
R with metallic objects, e.g. coins or metal
foil
R inside metallic objects, e.g. a metal case
This can impair the functionality of the KEY-
LESS-GO key.
Do not keep the KEYLESS-GO key in the tem-
perature-controlled cup holder (Y page 351).
Otherwise, the KEYLESS-GO key will not be
recognized.
If you lock the vehicle with the SmartKey's
remote control or with KEYLESS-GO, after a
short time:
R you will not be able to switch on the ignition
with the Start/Stop button.
R you will not be able to start the engine with
the Start/Stop button until the vehicle is
unlocked again.
If you lock the vehicle centrally using the but- ton on the front door (Y page 89), you can
continue to start the engine with the Start/
Stop button.
i The engine can be turned off while the
vehicle is in motion by pressing and holding
the Start/Stop button for approximately three seconds. This function operates inde-
pendently of the ECO start/stop automatic
engine switch-off function.
Key positions with KEYLESS-GO 0043
Start/Stop button
0044 Ignition lock
As soon as the ignition is switched on, all the
indicator lamps in the instrument cluster light up. If an indicator lamp does not go out afterstarting the engine or lights up while driving,
see (Y page 328).
If Start/Stop button 0043has not yet been
pressed, this corresponds to the SmartKey
being removed from the ignition.
X To switch on the power supply: press
Start/Stop button 0043once.
The power supply is switched on. You can
now activate the windshield wipers, for
example.
i The power supply is switched off again if:
R the driver's door is opened and
R you press Start/Stop button 0043twice
when in this position.
X To switch on the ignition: press Start/
Stop button 0043twice.
The ignition is switched on.
i The ignition is switched off when:
R the driver's door is opened and
R you press Start/Stop button 0043once
when in this position. 168
DrivingDriving an
d parking

Problems with the engine
Problem
Possible causes/consequences and
0050
0050Solutions The engine does not
start. The starter motor
can be heard. R
There is a malfunction in the engine electronics.
R There is a malfunction in the fuel supply.
X Before attempting to start the engine again, turn the SmartKey
in the ignition back to position 0or press the Start/Stop button
repeatedly until all indicator lamps in the instrument cluster go out.
X Try to start the engine again (Y page 169). Avoid excessively
long and frequent attempts to start the engine as these will drain
the battery.
If the engine does not start after several attempts:
X Consult a qualified specialist workshop. The engine does not
start. You cannot hear
the starter motor. The on-board voltage is too low because the battery is too weak or
discharged.
X Jump-start the vehicle (Y page 397).
If the engine does not start despite attempts to jump-start it:
X Consult a qualified specialist workshop. The starter motor was exposed to a thermal load that was too high.
X Allow the starter motor to cool down for approximately two
minutes.
X Try to start the engine again.
If the engine still does not start:
X Consult a qualified specialist workshop. Vehicles with a gaso-
line engine:
The engine is not run-
ning smoothly and is
misfiring. There is a malfunction in the engine electronics or in a mechanical
component of the engine management system.
X Only depress the accelerator pedal slightly.
Otherwise, non-combusted fuel may get into the catalytic con-
verter and damage it.
X Have the cause rectified immediately at a qualified specialist
workshop. The coolant tempera-
ture gauge shows a
value above 248 ‡
(120 †). The coolant level is too low. The coolant is too hot and the engine
is no longer being cooled sufficiently.
X Stop as soon as possible and allow the engine and the coolant to
cool down.
X Check the coolant level (Y page 375). Observe the warning
notes as you do so and add coolant if necessary. Driving
175Driving and parking Z

Opening the fuel filler flap
0043
To open the fuel filler flap
0044 To insert the fuel filler cap
0087 Fuel type to be used
0085 Tire pressure table
X Switch the engine off.
X Remove the SmartKey from the ignition
lock.
X KEYLESS-GO: open the driver’s door.
This corresponds to key position 0: "key
removed".
The driver’s door can be closed again.
X Press the fuel filler flap in the direction of
arrow 0043.
The fuel filler flap swings up.
X Turn the fuel filler flap counter-clockwise
and remove it.
X Insert the fuel filler cap into the holder
bracket on the inside of filler flap 0044.
X Completely insert the filler neck of the fuel
pump nozzle into the tank, hook in place
and refuel.
X Only fill the tank until the pump nozzle
switches off.
i Vehicles with a diesel engine: the filler
neck is designed for refueling at diesel fill-
ing pumps.
i Do not add any more fuel after the pump
stops filling for the first time. Otherwise,
fuel may leak out. Closing the fuel filler flap X
Replace the cap on the filler neck and turn
clockwise until it engages audibly.
X Close the fuel filler flap.
i Close the fuel filler flap before locking the
vehicle.
i If you are driving with the fuel filler cap
open, the 00B6reserve fuel warning lamp
flashes.
In addition, the 00B9Check Engine warning
lamp may light up (Y page 335).
A message appears in the multifunction
display (Y page 310).
For further information on warning and indi-
cator lamps in the instrument cluster, see
(Y page 335). Refueling
187Driving and parking Z

Servicing the brakes
!
If the red brake warning lamp lights up in
the instrument cluster and you hear a warn- ing tone while the engine is running, the
brake fluid level may be too low. Observe
additional warning messages in the multi-
function display.
The brake fluid level may be too low due to brake pad wear or leaking brake lines.
Have the brake system checked immedi-
ately. This work should be carried out at a
qualified specialist workshop.
! A function or performance test should
only be carried out on a 2-axle dynamom-
eter. If you are planning to have the vehicle tested on such a dynamometer, contact an
authorized Mercedes-Benz Center to
obtain further information first. Otherwise,
you could damage the drive train or the
brake system.
! Because ESP ®
is an automatic system,
the engine and ignition must be switched
off (SmartKey in position 0or 1or Start/
Stop button in position 0or 1) when the
electric parking brake is being tested on a
brake dynamometer (maximum
10 seconds).
Braking triggered automatically by ESP ®
may seriously damage the brake system.
All checks and maintenance work on the
brake system must be carried out at a quali-
fied specialist workshop. Consult a qualified
specialist workshop to arrange this.
Have brake pads installed and brake fluid
replaced at a qualified specialist workshop.
If the brake system has only been subject to
moderate loads, you should test the function- ality of your brakes at regular intervals. To doso, depress the brake pedal firmly when driv-
ing at a high speed. This improves the grip of
the brake pads.
You can find a description of Brake Assist
(BAS) on (Y page 69) or of BAS PLUS on
(Y page 69). Mercedes-Benz recommends that you only
have brake pads/linings installed on your
vehicle which have been approved for
Mercedes-Benz vehicles or which correspond
to an equivalent quality standard. Brake
pads/linings which have not been approved
for Mercedes-Benz vehicles or which are not
of an equivalent quality could affect your vehi-
cle's operating safety.
Mercedes-Benz recommends that you only
use brake fluid that has been specially
approved for your vehicle by Mercedes-Benz,
or which corresponds to an equivalent quality standard. Brake fluid which has not been
approved for Mercedes-Benz vehicles or
which is not of an equivalent quality could
affect your vehicle's operating safety.
High-performance brake system for
AMG vehicles The high-performance brake system is only
available on AMG vehicles.
The high-performance brake system is
designed for heavy loads. This may lead to
noise when braking. This will depend on:
R speed
R braking force
R environmental conditions, such as temper-
ature and humidity
The wear of individual components of the
brake system, such as the brake pads/linings
or brake discs, depends on the individual driv-
ing style and operating conditions.
For this reason, it is impossible to state a
mileage that will be valid under all circum-
stances. An aggressive driving style will lead
to high wear. You can obtain further informa- tion about this from your authorized
Mercedes-Benz Center.
New and replaced brake pads and discs only
reach their optimum braking effect after sev-
eral hundred kilometers of driving. Compen-
sate for this by applying greater force to the
brake pedal. Keep this in mind, and adapt Driving tips
197Driving and parking Z