2015 MERCEDES-BENZ GLK-CLASS SUV check engine

Problems with fuel and the fuel tank
ProblemPossible causes/consequences and M Solutions
Fuel is leaking from the
vehicle.The fuel line or the fuel tank is faulty.
GWARNING
Risk of explosion or fire.
X Turn the SmartKey to position 0 immediately and remove it
( Y page 149).
X Do not restart the engine under any circumstances.
X Consult a qualified specialist workshop.
The engine does not
start.The fuel tank of a vehicle with a diesel engine has been run com-
pletely dry.
X Refuel the vehicle with at least 5.3 US qt (5 liters) of diesel.
X Turn the ignition on for approximately ten seconds
(Y page 149).
X Start the engine continuously for up to ten seconds unt il it runs
smoothly.
If the engine does not start: X Turn the ignition on again for approximately ten seconds
(Y page 149).
X Start the engine again continuously for up to ten seco nds until it
runs smoothly.
If the engine does not start after three attempts:
X Consult a qualified specialist workshop.
The fuel filler flap can-
not be opened.The fuel filler flap is not unlocked.
X Unlock the vehicle ( Y page 78).
The SmartKey battery is discharged or nearly discharged.
X Unlock the vehicle using the mechanical key ( Y page 80).
The fuel filler flap is unlocked, but the opening mecha nism is jam-
med.
X Consult a qualified specialist workshop.
DEF (BlueTEC vehicles only)
Important notes on use
To function properly, BlueTEC exhaust gas
aftertreatment must be operated with the
reducing agent DEF. Adding DEF is one of the tasks performed during maintenance. Under
normal operating conditions, a tank of DEF
lasts until the next service due date.
When the supply of DEF is almost used up, theCheck Additive See Operator's Manual
Refueling165
Driving and parking
Z

Braking
Important safety notes
GWARNING
If you shift down on a slippery road surface in an attempt to increase the engine's braking
effect, the drive wheels could lose their grip.
There is an increased danger of skidding and
accidents.
Do not shift down for additional engine brak-
ing on a slippery road surface.
Downhill gradients
! On long and steep gradients, you must
reduce the load on the brakes by shifting
early to a lower gear. This allows you to take advantage of the engine braking effect and
helps avoid overheating and excessive
wear of the brakes.
When you take advantage of the engine
braking effect, a drive wheel may not turn
for some time, e.g. on a slippery road sur-
face. This could cause damage to the drive train. This type of damage is not covered bythe Mercedes-Benz warranty.
Heavy and light loads
GWARNING
If you rest your foot on the brake pedal while
driving, the braking system can overheat. This increases the stopping distance and can even
cause the braking system to fail. There is a
risk of an accident.
Never use the brake pedal as a footrest. Never
depress the brake pedal and the accelerator
pedal at the same time.
! Depressing the brake pedal constantly
results in excessive and premature wear to
the brake pads.
If the brakes have been subjected to a heavy load, do not stop the vehicle immediately.
Drive on for a short while. This allows the air-
flow to cool the brakes more quickly.
Wet roads
If you have driven for a long time in heavy rain without braking, there may be a delayed reac-
tion from the brakes when braking for the first time. This may also occur after the vehicle has
been washed.
You have to depress the brake pedal more
firmly. Maintain a greater distance from the
vehicle in front.
After driving on a wet road or having the vehi- cle washed, brake firmly while paying atten-
tion to the traffic conditions. This will warm up
the brake discs, thereby drying them more
quickly and protecting them against corro-
sion.
Limited braking performance on salt-
treated roads
If you drive on salted roads, a layer of salt
residue may form on the brake discs and
brake pads. This can result in a significantly
longer braking distance. R Brake occasionally to remove any possible
salt residue. Make sure that you do not
endanger other road users when doing so.
R Carefully depress the brake pedal and the
beginning and end of a journey.
R Maintain a greater distance to the vehicle
ahead.
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.
All checks and maintenance work on the
brake system must be carried out at a quali-
172Driving tips
Driving and parking

Ravoid sudden steering movements.
R brake carefully.
Driving on flooded roads
! Do not drive through flooded areas.
Check the depth of any water before driving through it. Drive slowly through standing
water. Otherwise, water may enter the
vehicle interior or the engine compartment.
This can damage the electronic compo-
nents in the engine or the automatic trans- mission. Water can also be drawn in by the
engine's air suction nozzles and this can
cause engine damage.
Prevent water from entering the vehicle inte-
rior or the engine compartment. If you must
drive through standing water, bear in mind
that:
R in the case of standing water, the water
level may be no higher than the lower edge
of the vehicle body
R you should drive no faster than at a walking
pace
Winter driving
GWARNING
If you shift down on a slippery road surface in an attempt to increase the engine's braking
effect, the drive wheels could lose their grip.
There is an increased danger of skidding and
accidents.
Do not shift down for additional engine brak-
ing on a slippery road surface.
GDANGER
If the exhaust pipe is blocked or adequate
ventilation is not possible, poisonous gases
such as carbon monoxide (CO) may enter thevehicle. This is the case, e.g. if the vehicle
becomes trapped in snow. There is a risk of
fatal injury.
If you leave the engine or the auxiliary heating
running, make sure the exhaust pipe and area
around the vehicle are clear of snow. To
ensure an adequate supply of fresh air, open a window on the side of the vehicle that is not
facing into the wind.
Have your vehicle winter-proofed at a quali-
fied specialist workshop at the onset of win-
ter.
Drive particularly carefully on slippery road
surfaces. Avoid sudden acceleration, steering and braking maneuvers. Do not use the cruise
control or DISTRONIC PLUS.
If the vehicle threatens to skid or cannot be
stopped when moving at low speed:
X Shift the transmission to position N.
The outside temperature indicator is not
designed to serve as an ice-warning device
and is therefore unsuitable for that purpose.
Changes in the outside temperature are dis-
played after a short delay.
Indicated temperatures just above the freez-
ing point do not guarantee that the road sur-
face is free of ice. The road may still be icy,
especially in wooded areas or on bridges. The vehicle could skid if you fail to adapt your
driving style. Always adapt your driving style
and drive at a speed to suit the prevailing
weather conditions.
You should pay special attention to road con-
ditions when temperatures are around freez-
ing point.
For more information on driving with snow
chains, see ( Y page 335).
For more information on driving with summer tires, see ( Y page 334).
Observe the notes in the "Winter operation"
section ( Y page 334).
174Driving tips
Driving and parking

are indicated by the flashing of red warning
lamp :. There are no further warning tones.
Switching on Blind Spot Assist X Make sure that Blind Spot Assist
(Y page 229) is activated in the on-board
computer.
X Turn the SmartKey to position 2 in the igni-
tion lock.
Warning lamps : in the exterior mirrors
light up red for approximately 1.5 seconds
and then turn yellow.
Towing a trailer
When you attach a trailer, make sure you have
correctly established the electrical connec-
tion. This can be accomplished by checking
the trailer lighting. In this event, Blind Spot
Assist is deactivated. The indicator lamp
lights up yellow in the exterior mirrors and the
Blind Spot Assist Currently UnavailZ
able See Operator's Manual message
appears in the multifunction display.
iYou can deactivate the indicator lamps in
the exterior mirrors.
To do so, switch off Blind Spot Assist when:
R the SmartKey is in position 2 in the igni-
tion lock
R the engine is not running
R the electrical connection to the trailer
has been established
Lane Keeping Assist
General notes
Lane Keeping Assist monitors the area in
front of your vehicle with camera :, which is
mounted at the top of the windshield. Lane
Keeping Assist detects lane markings on the
road and warns you before you leave your
lane unintentionally.
:Active Lane Keeping Assist camera
If you select
km on the on-board computer in
the
Display Unit Speed-/Odometer func-
tion ( Y page 230), Lane Keeping Assist is
active starting at a speed of 60 km/h. If the
miles display unit is selected, the assistance
range begins at 40 mph.
A warning may be given if a front wheel
passes over a lane marking. It will warn you by
means of intermittent vibration in the steer-
ing wheel for up to 1.5 seconds.
Important safety notes
If you fail to adapt your driving style, Lane
Keeping Assist can neither reduce the risk of
an accident nor override the laws of physics. Lane Keeping Assist cannot take into accountthe road, traffic and weather conditions. Lane
Keeping Assist is merely an aid. You are
responsible for the distance to the vehicle in
front, for vehicle speed, for braking in good
time and for staying in your lane.
GWARNING
Lane Keeping Assist may not always clearly
recognize lane markings.
In this case, Lane Keeping Assist may:
R give an unnecessary warning
R not give a warning
There is a risk of an accident.
Always pay particular attention to the traffic
situation and stay in lane, in particular if
warned by Lane Keeping Assist.
Driving systems205
Driving and parking
Z

Useful information
iThis 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.
iRead the information on qualified special-
ist workshops ( Y page 27).
Important safety notes
GWARNING
If you operate information systems and com-
munication equipment integrated in the vehi-
cle while driving, you will be distracted from
traffic conditions. You could also lose controlof the vehicle. There is a risk of an accident.
Only operate the equipment when the traffic
situation permits. If you are not sure that this
is possible, park the vehicle paying attention
to traffic conditions and operate the equip-
ment when the vehicle is stationary.
You must observe the legal requirements for
the country in which you are currently driving when operating the on-board computer.
GWARNING
If the instrument cluster has failed or mal-
functioned, you may not recognize function
restrictions in systems relevant to safety. The operating safety of your vehicle may be
impaired. There is a risk of an accident.
Drive on carefully. Have the vehicle checked
at a qualified specialist workshop immedi-
ately.
The on-board computer only shows messages
or warnings from certain systems in the mul- tifunction display. You should therefore make sure your vehicle is operating safely at all
times.
If the operating safety of your vehicle is
impaired, pull over as soon as it is safe to do
so. Contact a qualified specialist workshop.
For an overview, see the instrument panel
illustration (
Y page 33).
Displays and operation
Coolant temperature display
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.
The coolant temperature gauge is in the
instrument cluster on the left-hand side.
Under normal operating conditions and with
the specified coolant level, the coolant tem-
perature may rise to 248 ‡ (120 †).
! A display message is shown if the coolant
temperature is too high.
If the coolant temperature is over 248 ‡
(120 †), do not continue driving. The
engine will otherwise be damaged.
Tachometer
The red band in the tachometer indicates the
engine's overrevving range.
! Do not drive in the overrevving range, as
this could damage the engine.
The fuel supply is interrupted to protect the
engine when the red band is reached.
220Displays and operation
On-board computer and displays

Display messagesPossible causes/consequences and M Solutions
b
Check Left Daytime
Running
Light or Check
Right Daytime RunZ
ning Light
The left or right-hand daytime running lamp is faulty.
X Visit a qualified specialist workshop.
b
Active Light SysZ
tem Inoperative
The active light function is faulty.
X Visit a qualified specialist workshop.
b
Malfunction See
Operator's Manual
The exterior lighting is defective.
X Visit a qualified specialist workshop.
b
Auto Lamp Function
Inoperative
The light sensor is defective.
X Visit a qualified specialist workshop.
b
Switch Off Lights
The lights are still switched on when you leave the vehicle. A
warning tone also sounds.
X Turn the light switch to Ã.
Engine
Display messagesPossible causes/consequences and M Solutions
+
Check Coolant
Level See OperaZ
tor's Manual
The coolant level is too low.
! Avoid making long journeys with too little coolant in the engine
cooling system. The engine will otherwise be damaged.
X Add coolant, observing the warning notes before doing so
(Y page 303).
X If coolant needs to be added more often than usual, have the
engine coolant system checked at a qualified specialist work-
shop.
?The fan motor is faulty. XAt coolant temperatures below 248 ‡ (120 †), drive to the
nearest qualified specialist workshop.
X Avoid subjecting the engine to heavy loads, e.g. drivin g in moun-
tainous terrain, and stop-and-go traffic.
246Display messages
On-board computer and displays

Display messagesPossible causes/consequences and M Solutions
#The battery is not being charged.
A warning tone also sounds.
Possible causes are: R
a defective alternator
R a torn poly-V-belt
R a malfunction in the electronics
X Pull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.
X Secure the vehicle against rolling away ( Y page 168).
X Open the hood.
X Check whether the poly-V-belt is torn.
If the poly-V-belt is torn:
! Do not continue driving. The engine could otherwise ov erheat.
X Consult a qualified specialist workshop.
If the poly-V-belt is not damaged: X Visit a qualified specialist workshop.
4
Check Engine Oil
At Next Refueling
The engine oil level has dropped to the minimum level.
A warning tone also sounds.
! Avoid long journeys with too little engine oil. The engine will
otherwise be damaged.
X Check the oil level when next refueling, at the latest
(Y page 301).
X If necessary, add engine oil ( Y page 302).
X Have the engine checked at a qualified specialist workshop if
engine oil needs to be added more often than usual.
Information on approved engine oils can be obtained from any
qualified specialist workshop or on the Internet at http://
bevo.mercedes-benz.com.
8
Fuel Level Low
The fuel level has dropped into the reserve range. X Refuel at the nearest gas station.
CThere is only a very small amount of fuel in the fuel tank.
X Refuel at the nearest gas station without fail.
248Display messages
On-board computer and displays

Display messagesPossible causes/consequences and M Solutions
8
Gas Cap Loose
The fuel system pressure is too low. The fuel filler cap i s not closed
correctly or the fuel system is leaking.
X Check that the fuel filler cap is correctly closed.
If the fuel filler cap is not correctly closed: X Close the fuel filler cap.
If the fuel filler cap is correctly closed: X Visit a qualified specialist workshop.
¸
Replace Air Filter
Vehicles with a diesel engine: the engine air filter is di rty and must
be replaced.
X Visit a qualified specialist workshop.
!
Check Fuel Filter
Vehicles with a diesel engine: there is water in the fuel filter. The
water must be drained off.
X Visit a qualified specialist workshop.
¯
Refill AdBlue At
Workshop See OperZ
ator's Manual
The DEF level has fallen below the reserve range. A warning tone
also sounds.
X Have DEF refilled as soon as possible at a qualified specialist
workshop.
¯
Refill AdBlue At
Workshop No Start
in .. km
The DEF level is only sufficient for the indicated dista nce. A warn-
ing tone also sounds.
X Have DEF refilled as soon as possible at a qualified specialist
workshop.
¯
Refill AdBlue At
Workshop Eng.
Start Not Possible
The DEF tank is empty. A warning tone also sounds. You can no
longer start the engine.
X Consult a qualified specialist workshop immediately.
¯
Check AdBlue See
Operator's Manual
The DEF system is malfunctioning. A warning tone also sounds.
X Visit a qualified specialist workshop.
Display messages249
On-board computer and displays
Z