check engine MERCEDES-BENZ GLS SUV 2018 Service Manual

Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
÷NThe yellow ESP®warning lamp flashes while the vehicle is in motion.
ESP®or traction control has intervened because there is a risk of skidding or at
least one wheel has started to spin.
Cruise control or Distance Pilot DISTRONIC is deactivated.
XWhen pulling away, only depress the accelerator pedal as far as necessary.
XEase off the accelerator pedal while the vehicle is in motion.
XAdapt your driving style to suit the road and weather conditions.
XDo not deactivate ESP®.
In rare cases (
Ypage 71), it may be best to deactivate ESP®.
Observe the important safety notes on ESP®(Ypage 70).
åN The yellow ESP®OFF warning lamp is lit while the engine is running.
ESP®is deactivated.
GWARNING
If ESP
®is switched off, ESP®is unable to stabilize the vehicle.
Further driving systems or driving safety systems are thus restricted, e.g. Active
Blind Spot Assist. The system does not perform course-correcting brake applica-
tions.
There is an increased risk of skidding and an accident.
XReactivate ESP®.
In rare cases (
Ypage 71), it may be best to deactivate ESP®.
Observe the important safety notes on ESP®(Ypage 70).
XAdapt your driving style to suit the road and weather conditions.
If ESP
®cannot be activated:
XDrive on carefully.
XContact a qualified specialist workshop and have ESP®checked.
Warning and indicator lamps in the instrument cluster285
On-board computer and displays
Z

Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
F!NF (USA only), !(Canada only): the red indicator lamp for the electric
parking brake flashes or is lit and/or the yellow warning lamp for the electric
parking brake is lit.
XObserve the additional display messages in the multifunction display.
6N The red restraint system warning lamp is lit while the engine is running.
The restraint system is malfunctioning.
GWARNING
The air bags or Emergency Tensioning Devices may either be triggered uninten-
tionally or, in the event of an accident, may not be triggered.
There is an increased risk of injury.
XObserve the additional display messages in the multifunction display.
XDrive on carefully.
XContact a qualified specialist workshop and have the restraint system checked.
For further information about the restraint system, see (
Ypage 44).
Warning and indicator lamps in the instrument cluster287
On-board computer and displays
Z

Engine
Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
;NThe yellow Check Engine warning lamp lights up while the engine is running.
There may be a malfunction, for example:
Rin the engine management
Rin the fuel injection system
Rin the exhaust system
Rin the ignition system (for vehicles with gasoline engines)
Rin the fuel system
The emission limit values may be exceeded and the engine may be in emergency
mode.
XVisit a qualified specialist workshop immediately.
Vehicles with a diesel engine: the fuel tank has been run dry (
Ypage 158).
XStart the engine three to four times after refueling.
If the yellow Check Engine warning lamp goes out, emergency running mode is
canceled. The vehicle need not be checked.
In some states, you must immediately visit a qualified specialist workshop as soon
as the yellow Check Engine warning lamp lights up. This is due to the legal require-
ments in effect in these states. If in doubt, check whether such legal regulations
apply in the state in which you are currently driving.
8N The yellow reserve fuel warning lamp lights up while the engine is running.
The fuel level has dropped into the reserve range.
XRefuel at the nearest gas station.
8N The yellow reserve fuel warning lamp flashes while the vehicle is in motion.
In addition, the ;Check Engine warning lamp may light up.
The fuel filler cap is not closed correctly or the fuel system is leaking.
XCheck that the fuel filler cap is correctly closed.
XIf the fuel filler cap is not correctly closed: close the fuel filler cap.
XIf the fuel filler cap is closed:visit a qualified specialist workshop.
?NThe red coolant warning lamp lights up while the engine is running and the
coolant temperature gauge is at the start of the scale.
The temperature sensor for the coolant temperature gauge is malfunctioning.
The coolant temperature is no longer being monitored. There is a risk of engine
damage if the coolant temperature is too high.
XPull over and stop the vehicle safely and switch off the engine, paying attention
to road and traffic conditions. Do not continue driving under any circumstances.
XSecure the vehicle against rolling away (Ypage 161).
XConsult a qualified specialist workshop.
288Warning and indicator lamps in the instrument cluster
On-board computer and displays

Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
?NThe red coolant warning lamp comes on while the engine is running.
The coolant level is too low.
If the coolant level is correct, the airflow to the engine radiator may be blocked or
the electric engine radiator fan may be defective.
The coolant is too hot and the engine is no longer being cooled sufficiently.
XObserve the additional display messages in the multifunction display.
XPull over and stop the vehicle safely and switch off the engine, paying attention
to road and traffic conditions.
XSecure the vehicle against rolling away (Ypage 161).
XLeave the vehicle and keep a safe distance from the vehicle until the engine has cooled down.
XCheck the coolant level and add coolant, observing the warning notes
(Ypage 328).
XIf you have to add coolant frequently, have the engine cooling system checked.
XMake sure that the air supply to the engine radiator is not blocked, e.g. by snow,
slush or ice.
XDo not start the engine again until the coolant temperature is below 248 ‡
(120 †). Otherwise, the engine could be damaged.
XDrive to the nearest qualified specialist workshop.
XAvoid heavy loads on the engine as you do so, e.g. driving in mountainous terrain
and stop-and-go traffic.
?N The red coolant warning lamp comes on while the engine is running.
The coolant temperature has exceeded 248 ‡ (120 †). The airflow to the engine
radiator may be blocked or the coolant level may be too low.
GWARNING
The engine is not being cooled sufficiently and may be damaged.
Do not drive when your engine is overheated. This can cause some fluids which
may have leaked into the engine compartment to catch fire.
Steam from the overheated engine can also cause serious burns which can occur
just by opening the hood.
There is a risk of injury.
XObserve the additional display messages in the multifunction display.
XPull over and stop the vehicle safely and switch off the engine, paying attention
to road and traffic conditions.
XSecure the vehicle against rolling away (Ypage 161).
XLeave the vehicle and keep a safe distance from the vehicle until the engine has
cooled down.
XCheck the coolant level and add coolant, observing the warning notes
(Ypage 328).
XIf you have to add coolant frequently, have the engine cooling system checked.
XMake sure that the air supply to the engine radiator is not blocked, e.g. by snow,
slush or ice.
Warning and indicator lamps in the instrument cluster289
On-board computer and displays
Z

XMake sure that the windshield wipers are
turned off.
XPull release lever:on the hood.
The hood is released.
XReach into the gap, pull hood catch handle ;
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
XLower the hood and let it fall from a height of
approximately 8 in (20 cm).
XCheck 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. such as with a thermal mat or
insect protection cover. Otherwise, the values of the European on-board diagnostics may be
affected. Some of these readings are required
by law and must be accurate at all times.
Engine oil
Important safety notes
GWARNING
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.
GWARNING
Opening the hood when the engine is over-
heated or when there is a fire in the engine
compartment could expose you to hot gases
or other service products. There is a risk of
injury.
Let an overheated engine cool down before
opening the hood. If there is a fire in the
engine compartment, keep the hood closed
and contact the fire department.
GWARNING
If engine oil comes into contact with hot com- ponents in the engine compartment, it may
ignite. There is a risk of fire and injury.
Make sure that engine oil is not spilled next to
the filler neck. Let the engine cool down and
thoroughly clean the engine oil off the com-
ponents before starting the engine.
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.
326Engine compartment
Maintenance and care

When checking the oil level:
Rpark the vehicle on a level surface.
Rthe engine should be switched off for approx-
imately five minutes if the engine is at normal
operating temperature.
Rif the engine is not at normal operating tem-
perature, 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
Example: vehicles with a gasoline engine
Example: vehicles with a diesel engine
XPull oil dipstick :out of the dipstick tube.
XWipe off oil dipstick :.
XSlowly slide oil dipstick :into the guide tube
to the stop, and take it out again.
If the level is between MIN mark =and MAX
mark ;, the oil level is correct.
XIf the oil level has dropped to MIN mark =or
below, add 1.1 US qt (1.0 liter) engine oil.
Adding engine oil
HEnvironmental note
When adding oil, take care not to spill any. If
oil enters the soil or waterways, it is harmful to
the environment.
!Use only engine oils and oil filters that are
approved for vehicles with a service system. A list of the engine oils and oil filters that have
been tested and approved in accordance with
Mercedes-Benz Specifications for Service
Products is available at any authorized
Mercedes-Benz Center.
The following cause engine failure or damage
to the exhaust system:
RUse of engine oils and oil filters that have
not been expressly approved for the service
system
RReplacement of engine oil and oil filter after
the replacement interval specified by the
service system has expired
RUse of engine oil additives
!Do not add too much oil. adding too much
engine oil can result in damage to the engine
or to the catalytic converter. Have excess
engine oil siphoned off.
Example: engine oil cap
XTurn cap :counter-clockwise and remove it.
XAdd engine oil.
If the oil level is at or below the MIN mark on
the oil dipstick, add 1.1 US qt (1.0 liter) of
engine oil.
XReplace cap :on the filler neck and tighten
clockwise.
Ensure that the cap locks into place securely.
XCheck the oil level again with the oil dipstick
(Ypage 327).
Engine compartment327
Maintenance and care
Z

Further information on engine oil (Ypage 389).
Additional service products
Important safety notes
GWARNING
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.
GWARNING
The cooling system is pressurized, particularly
when the motor is warm. If you open the cap,
you could be scalded if hot coolant sprays out.
There is a risk of injury.
Let the engine cool down before you open the
cap. Wear gloves and eye protection. Slowly
open the cap to relieve pressure.
The coolant level may only be checked and cool-
ant refilled when the engine and engine cooling
system have cooled down.
GWARNING
Windshield washer concentrate could ignite if it comes into contact with hot engine compo-
nents or the exhaust system. There is a risk of
fire and injury.
Make sure that no windshield washer con-
centrate is spilled next to the filler neck.
Checking coolant level
XPark the vehicle on a level surface.
Only check the coolant level when the vehicleis on a level surface and the engine has cooled
down.
XTurn the SmartKey to position 2in the igni-
tion lock (Ypage 140).
On vehicles with KEYLESS-GO, press the
Start/Stop button twice (
Ypage 142).
XCheck the coolant temperature gauge in the
multifunction display.
The coolant temperature must be below
158 ‡ (70 †).
XTurn the SmartKey to position in the ignition
lock u(Ypage 140).
XOn vehicles with KEYLESS-GO, press the
Start/Stop button (Ypage 142).
XPress the Start/Stop button (Ypage 142).
XSlowly turn cap :half a turn counter-clock-
wise and allow excess pressure to escape.
XTurn cap :further counter-clockwise and
remove it.
If the coolant is at the level of marker bar =
in the filler neck when cold, there is enough
coolant in coolant expansion tank ;.
If the coolant level is approximately 0.6 in
(1.5 cm) above marker bar =in the filler neck
when warm, there is enough coolant in expan-
sion tank ;.
XIf necessary, add coolant that has been tested
and approved by Mercedes-Benz.
XReplace cap :and turn it clockwise as far as
it will go.
For further information on coolant, see
(
Ypage 390).
328Engine compartment
Maintenance and care

A qualified specialist workshop will reset the
ASSYST service interval display after the service
work has been carried out. You can also obtain
further information on maintenance work, for
example.
Special service requirements
The specified maintenance interval takes only
the normal operation of the vehicle into
account. Under increased load on the vehicle,
maintenance work must be carried out more
frequently, for example:
RRegular city driving with frequent intermedi-
ate stops
RIf the vehicle is primarily used to travel short
distances
RUse in mountainous terrain or on poor road
surfaces
RIf the engine is often left idling for long periods
Under these or similar conditions, have, for
example, the air filter, engine oil and oil filter
replaced or changed more frequently. Under
arduous operating conditions, the tires must be
checked more often. Further information can be
obtained at a qualified specialist workshop.
Driving abroad
An extensive Mercedes-Benz Service network is
also available in other countries. You can obtain
further information from any authorized
Mercedes-Benz Center.
Care
General notes
HEnvironmental note
Dispose of empty packaging and cleaning
cloths in an environmentally responsible man-
ner.
!When cleaning your car, do not use:
Rdry, coarse or hard cloths
Rabrasive cleaning agents
Rsolvents
Rcleaning agents containing solvents
Do not scrub.
Do not touch the surfaces and films with hard
objects, e.g. rings or ice scrapers. Otherwise, you may scratch or damage the surfaces and
films.
!Do not park your vehicle for a long period of
time directly after cleaning, particularly after
cleaning the wheel rim with wheel cleaner.
Wheel cleaner can lead to the increased cor-
rosion of the brake discs and pads. Therefore,
drive for a few minutes after cleaning. By
heating up the brakes, the brake discs and
pads dry. The vehicle can then be parked for a
long period of time.
Regular care of your vehicle is a condition for
retaining the quality in the long term.
Use care products and cleaning agents recom-
mended and approved by Mercedes-Benz.
Washing the vehicle and cleaning the
paintwork
Automatic car wash
GWARNING
Braking efficiency is reduced after washing
the vehicle. There is a risk of an accident.
After the vehicle has been washed, brake
carefully while paying attention to the traffic
conditions until full braking power is restored.
!Before driving into an automatic car wash,
make sure that it is suitable for the dimen-
sions of the vehicle. In particular, make sure
that:
Rthere is enough ground clearance between
the vehicle underbody and the guide rails of
the automatic car wash.
Rthe clearance width of the automatic car
wash is sufficient, particularly the width of
the guide rails.
Ryou enter the automatic car wash straight
and in the center of the guide rails in order
to avoid damaging the tires or wheel rims.
Fold in the exterior mirrors before the vehicle
is washed. The exterior mirrors could other-
wise be damaged.
!When Distance Pilot DISTRONIC or the
HOLD function is activated, the vehicle
brakes automatically in certain situations.
330Care
Maintenance and care

XIf possible, bring the front wheels into the
straight-ahead position.
XVehicles with the AIRMATIC package:
make sure that the normal vehicle level is
selected (
Ypage 190).
XVehicles with the Off-Road Engineering
package:make sure that the normal level is
selected (
Ypage 184).
XSwitch off the engine.
XVehicles without KEYLESS-GO: remove the
SmartKey from the ignition lock.
XVehicles with KEYLESS-GO: open the driv-
er's door.
The vehicle electronics are now in position
u. This means no SmartKey is in the ignition
lock.
XVehicles with KEYLESS-GO: remove the
Start/Stop button from the ignition lock
(
Ypage 140).
XMake sure that the passengers are not endan-
gered as they do so. Make sure that no one is near the danger area while a wheel is being
changed. Anyone who is not directly assisting
in the wheel change should, for example,
stand behind the barrier.
XGet out of the vehicle. Pay attention to traffic
conditions when doing so.
XClose the driver's door.
XUnload heavy luggage.
iOnly operate the tire inflation compressor
using a 12 V socket, even if the ignition is
turned off (
Ypage 312).
An emergency cut-out ensures that the on-
board voltage does not drop too low. If the on-
board voltage is too low, the power to the
sockets is automatically cut. This ensures
that there is sufficient power to start the
engine.
MOExtended tires (tires with run-flat
properties)
General notes
With MOExtended tires (tires with run flat char-
acteristics), you can continue to drive your vehi-
cle even if there is a total loss of pressure in one
or more tires. The affected tire must not show
any clearly visible damage.
You can recognize a MOExtended tire by the
MOExtended marking which appears on the sidewall of the tire. You will find this marking
next to the tire size designation, the load-bear-
ing capacity and the speed index (
Ypage 369).
MOExtended tires may only be used in conjunc-
tion with an active tire pressure loss warning
system or with an active tire pressure monitor.
If a pressure loss warning message appears
in the multifunction display:
Robserve the instructions in the display mes-
sages (Ypage 273).
Rcheck the tire for damage
Rif driving on, observe the following notes
The driving distance possible in run-flat mode is
approximately 50 miles (80 km) when the vehi-
cle is partially laden and approximately 18 miles
(30 km) when the vehicle is fully laden.
In addition to the vehicle load, the driving dis-
tance possible depends upon:
RVehicle speed
RRoad condition
ROutside temperature
The driving distance possible in run-flat mode
may be reduced by extreme driving conditions
or maneuvers, or it can be increased through a
moderate style of driving.
The driving distance possible in run-flat mode is
counted from the moment the tire pressure loss
warning appears in the multifunction display.
You must not exceed a maximum permissible
speed of 50 mph (80 km/h).
iWhen replacing one or all tires, please
observe the following specifications for your
vehicle's tires:
Rsize
Rtype and
Rthe "MOExtended" mark
If a tire has gone flat and cannot be replaced with a MOExtended tire, a standard tire may
be used as a temporary measure. Make sure
that you use the proper size and type (sum-
mer or winter tire).
iVehicles equipped with MOExtended tires
are not equipped with a TIREFIT kit at the fac-
tory. It is therefore recommended that you
additionally equip your vehicle w

ith a TIREFIT
kit if you mount tires that do not feature run-
flat properties, e.g. winter tires. A TIREFIT kit
may be obtained from a qualified specialist
workshop.
340Flat tire
Breakdown assistance

Charging the 12 V battery
GWARNING
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.
GWARNING
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.
GWARNING
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 maximum
charging voltage of 14.8 V.
!Only charge the battery using the jump-
starting connection point.
The jump-starting connection point is in the
engine compartment (
Ypage 346).
XOpen the hood.
XConnect the battery charger to the positive
terminal and ground point in the same order
as when connecting the donor battery in the
jump-starting procedure (
Ypage 346).
Keep away from fire and open flames. Do not
lean over a battery. 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 specially adapted for Mercedes-Benz vehi-
cles and tested and approved by Mercedes-
Benz is available as an accessory. It permits the
charging of the battery in its installed position.
Contact an authorized Mercedes-Benz Center
for further information and availabilit y. Read t
he
battery charger's operating instructions before
charging the battery.
If, at low temperatures, the indicator lamps/
warning lamps in the instrument cluster do not
light up, it is highly 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
For the jump-starting procedure, use only the jump-starting connection point in the engine com-
partment, consisting of a positive terminal and a ground point.
GWARNING
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.
GWARNING
During charging and jump-starting, explosive gases can escape from the battery. There is a risk of an explosion.
346Jump-starting
Breakdown assistance