2014 MERCEDES-BENZ GLK-CLASS SUV fuel pressure

Engine
Problem Possible causes/consequences and
M
MSolutions ;
The yellow Check
Engine warning lamp
lights up while the
engine is running.
There may be a malfunction, for example:
R
in the engine management
R in the fuel injection system
R in the exhaust system
R in the ignition system
R in the fuel system
The emission limit values may be exceeded and the engine may
be in emergency mode.
X Have the vehicle checked as soon as possible at a qualified
specialist workshop.
i 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 requirements in effect in
these states. If in doubt, check whether such legal regulations
apply in the state in which you are currently driving. 8
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 system pressure is too low. The fuel filler cap is not closed
correctly or the fuel system is leaking.
X Observe the additional display messages in the multifunction
display.
X Check that the fuel filler cap is correctly closed.
X If the fuel filler cap is not correctly closed: close the fuel filler
cap.
X If the fuel filler cap is closed: visit a qualified specialist
workshop. 8
The yellow reserve fuel
warning lamp lights up
while the engine is
running.
The fuel level has dropped into the reserve range.
X
Refuel at the nearest gas station. 268
Warning and indicator lamps in the instrument clusterOn-board computer and displays

X
Slowly turn cap :half a turn counter-
clockwise and allow excess pressure to
escape.
X Turn 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 fuel
filler neck when warm, there is enough
coolant in expansion tank ;.
X If necessary, add coolant that has been
tested and approved by Mercedes-Benz.
X Replace cap :and turn it clockwise as far
as it will go.
For further information on coolant, see
(Y page 372).
Adding washer fluid to the windshield
washer system/headlamp cleaning
system G
WARNING
Certain components in the engine
compartment, 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. G
WARNING
Windshield washer concentrate is highly
flammable. If it comes into contact with hot
engine components or the exhaust system it
could ignite. There is a risk of fire and injury.
Make sure that no windshield washer
concentrate is spilled next to the filler neck. X
To open: pull cap:upwards by the tab.
X Add the premixed washer fluid.
X To close: press cap :onto the filler neck
until it engages.
The washer fluid reservoir is used for both the
windshield washer system and the headlamp
cleaning system.
If the washer fluid level drops below the
recommended minimum of 1 liter, a message
appears in the multifunction display
prompting you to add washer fluid
(Y page 259).
Further information on windshield washer
fluid/antifreeze (Y page 373). Care
General notes
! For cleaning your vehicle, do not use any
of the following:
R dry, rough or hard cloths
R abrasive cleaning agents
R solvents
R cleaning agents containing solvents
Do not scrub.
Do not touch the surfaces or protective
films with hard objects, e.g. a ring or ice
scraper. You could otherwise scratch or
damage the surfaces and protective film. Care
305Maintenance and care Z

Useful information
i This Operator's Manual describes all
models and all standard and optional
equipment 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
specialist workshops: (Y page 27).Important safety notes
G
WARNING
If wheels and tires of the wrong size are used,
the wheel brakes or suspension components
may be damaged. There is a risk of an
accident.
Always replace wheels and tires with those
that fulfill the specifications of the original
part.
When replacing wheels, make sure to use the
correct:
R designation
R model
When replacing tires, make sure to use the
correct:
R designation
R manufacturer
R model G
WARNING
A flat tire severely impairs the driving,
steering and braking characteristics of the
vehicle. There is a risk of accident.
Tires without run-flat characteristics:
R do not drive with a flat tire.
R immediately replace the flat tire with your
emergency spare wheel or spare wheel, or
consult a qualified specialist workshop. Tires with run-flat characteristics:
R
pay attention to the information and
warning notices on MOExtended tires (tires
with run-flat characteristics).
Accessories that are not approved for your
vehicle by Mercedes-Benz or that are not
being used correctly can impair operating
safety.
Before purchasing and using non-approved
accessories, visit a qualified specialist
workshop and inquire about:
R suitability
R legal stipulations
R factory recommendations
Information on the dimensions and types of
wheels and tires for your vehicle can be found
in the "Wheel/tire combinations" section
(Y page 359).
Information on air pressure for the tires on
your vehicle can be found:
R on the vehicle's Tire and Loading
Information placard on the B-pillar
R on the tire pressure label on the fuel filler
flap
R in the "Tire pressure" section
Modification work on the brake system and
wheels is not permitted. The use of wheel
spacers or brake dust shields is not
permitted. This invalidates the general
operating permit for the vehicle.
i Further information on wheels and tires
can be obtained at any qualified specialist
workshop. Operation
Information on driving
R If the vehicle is heavily loaded, check the
tire pressures and correct them if
necessary.
R While driving, pay attention to vibrations,
noises and unusual handling 330
OperationWheels and tires

Tire pressure
Tire pressure specifications
Operation with a trailer: the applicable
value for the rear tires is the maximum tire
pressure value stated in the table inside the
fuel filler flap. G
WARNING
Underinflated or overinflated tires pose the
following risks:
R the tires may burst, especially as the load
and vehicle speed increase.
R the tires may wear excessively and/or
unevenly, which may greatly impair tire
traction.
R the driving characteristics, as well as
steering and braking, may be greatly
impaired.
There is a risk of an accident.
Follow recommended tire inflation pressures
and check the pressure of all the tires
including the spare wheel:
R monthly, at least
R if the load changes
R before beginning a long journey
R under different operating conditions, e.g.
off-road driving
If necessary, correct the tire pressure.
The recommended tire pressures for the tires
mounted at the factory can be found on the
labels described here.
1.) Tire and Loading Information placard
on the B-pillar on the driver's side of the
vehicle (Y page 342).
The Tire and Loading Information placard
contains the recommended tire pressures for
cold tires on a fully loaded vehicle and for the
maximum permissible vehicle speed.
i The specifications given on the following
Tire and Loading Information placard are
examples. Tire pressure specifications are
vehicle-specific and may deviate from the
data shown here. The tire pressures applicable to your vehicle can be found on
the Tire and Loading Information placard on
your vehicle.
:
Recommended tire pressures
Option 2) Tire pressure table on the inside
of the fuel filler flap.
The tire pressure table contains the
recommended pressures for cold tires for
various operating conditions, i.e. differing
load and speed conditions.
i Specifications shown in the examples of
tire pressure tables are for illustration
purposes only. Tire pressure specifications
are vehicle-specific and may deviate from
the data shown here. Tire pressure
specifications applicable to your vehicle
are located in your vehicle's tire pressure
table. Example: tire pressure table for all tires permitted
for this vehicle by the factory
If a tire size precedes a tire pressure, the tire
pressure information following is only valid
for that tire size. The load conditions "partially
laden" and "fully laden" are defined in the334
Tire pressureWheels and tires

table for different numbers of occupants and
amounts of luggage. The actual number of
seats may differ. Example: tire pressure table with tire dimensions
Some tire pressure tables show only the rim
diameters instead of the full tire size, e.g.
R18 . The rim diameter is part of the tire size
and can be found on the tire sidewall
(Y page 348). If the tire pressures have been set to the
lower values for lighter loads and/or lower
road speeds, the pressures should be reset
to the higher values:
R if you want to drive with an increased load
and/or
R if you want to drive at higher road speeds.
i The tire pressures for increased loads
and/or higher road speeds, shown in the
tire pressure table, may have a negative
effect on driving comfort.
i For vehicles towing a trailer, the full load
value on the tire pressure label located on the inside of the fuel filler flap is valid for
the rear axle.
Option 3) The tire pressure for the
emergency/collapsible spare wheel
(depending on vehicle equipment) can be
found:
R printed in yellow on the rim of the
emergency/collapsible spare wheel
R in the "Wheel and tire combinations"
section ( Ypage 359) in this Operator's
Manual
R on the Tire and Loading Information placard
on the B-pillar on the driver's side
If the tire pressure is not set correctly, this
can lead to an excessive build up of heat and
a sudden loss of pressure.
For more information, contact a qualified
specialist workshop. Important notes on tire pressure
G
WARNING
If the tire pressure drops repeatedly, the
wheel, valve or tire may be damaged. Tire
pressure that is too low may result in a tire
blow-out. There is a risk of an accident.
R Check the tire for foreign objects.
R Check whether the wheel is losing air or the
valve is leaking.
If you are unable to rectify the damage,
contact a qualified specialist workshop. G
WARNING
If you fit unsuitable accessories onto tire
valves, the tire valves may be overloaded and
malfunction, which can cause tire pressure
loss. Due to their design, retrofitted tire
pressure monitors keep the tire valve open.
This can also result in tire pressure loss. There
is a risk of an accident.
Only screw the standard valve cap or other
valve caps approved by Mercedes-Benz for
your vehicle onto the tire valve. Tire pressure
335Wheels and tires Z

To test tire pressure, use a suitable tire
pressure gauge. The outer appearance of a
tire does not permit any reliable conclusion
about the tire pressure. On vehicles equipped
with the electronic tire pressure monitoring
system, the tire pressure can be checked
using the on-board computer.
The tire temperature and pressure increase
when the vehicle is in motion. This is
dependent on the driving speed and the load.
Therefore, you should only correct tire
pressures when the tires are cold.
The tires are cold:
R if the vehicle has been parked without
direct sunlight on the tires for at least three
hours and
R if the vehicle has not been driven further
than 1 mile (1.6 km)
The tire temperature changes depending on
the outside temperature, the vehicle speed
and the tire load. If the tire temperature
changes by 18 ‡ (10 †), the tire pressure
changes by approximately 10 kPa (0.1 bar/
1.5 psi). Take this into account when
checking the pressure of warm tires and only
correct the tire pressure if it is too low for the
current operating conditions. If you check the
tire pressure when the tires are warm, the
resulting value will be higher than if the tires
were cold. This is normal. Do not reduce the
tire pressure to the value specified for cold
tires. The tire pressure would otherwise be
too low.
Observe the recommended tire pressures for
cold tires:
R on the Tire and Loading Information placard
on the B-pillar on the driver's side
R in the tire pressure table on the inside of
the fuel filler flap
R printed in yellow on the rim of the
emergency/collapsible spare wheel
(depending on vehicle equipment) Underinflated or overinflated tires
Underinflation G
WARNING
Tires with pressure that is too low can
overheat and burst as a consequence. In
addition, they also suffer from excessive and/
or irregular wear, which can severely impair
the braking properties and the driving
characteristics. There is a risk of an accident.
Avoid tire pressures that are too low in all the
tires, including the spare wheel.
Underinflated tires may:
R wear quickly and unevenly
R have an adverse effect on fuel consumption
R overheat, leading to tire defects
R have an adverse effect on handling
characteristics
Overinflation G
WARNING
Tires with excessively high pressure can burst
because they are damaged more easily by
road debris, potholes etc. In addition, they
also suffer from irregular wear, which can
severely impair the braking properties and the
driving characteristics. There is a risk of an
accident.
Avoid tire pressures that are too high in all the
tires, including the spare wheel.
Overinflated tires may:
R have an adverse effect on handling
characteristics
R wear quickly and unevenly
R be more susceptible to damage
R have an adverse effect on ride comfort
R increase the braking distance
Maximum tire pressures Never exceed the maximum permissible tire
inflation pressure. Always observe the336
Tire pressureWheels and tires

recommended tire pressure for your vehicle
when adjusting the tire pressure
(Y page 334). :
Example: maximum permissible tire
pressure
i The actual values for tires are vehicle-
specific and may deviate from the values in
the illustration. Checking the tire pressures
Important safety notes Observe the "tire pressure information"
section (Y page 334).
Information on air pressure for the tires on
your vehicle can be found:
R on the vehicle's Tire and Loading
Information placard on the B-pillar
R on the tire pressure label on the fuel filler
flap
R in the "Tire pressure information" section
Checking tire pressures manually To determine and set the correct tire
pressure, proceed as follows:
X Remove the valve cap of the tire that is to
be checked.
X Press the tire pressure gauge securely onto
the valve.
X Read the tire pressure and compare it with
the recommended value on the Tire and
Loading Information placard on the
B-pillar on the driver's side of your vehicle. X
If necessary, increase the tire pressure to
the recommended value (Y page 334).
X If the tire pressure is too high, release air
by pressing down the metal pin in the valve
using the tip of a pen, for example. Then,
check the tire pressure again using the tire
pressure gauge.
X Screw the valve cap onto the valve.
X Repeat these steps for the other tires. Tire pressure loss warning system
(Canada only)
General notes While the vehicle is in motion, the tire
pressure loss warning system monitors the
set tire pressure using the rotational speed of
the wheels. This enables the system to detect
significant pressure loss in a tire. If the speed
of rotation of a wheel changes as a result of
a loss of pressure, a corresponding warning
message will appear in the multifunction
display.
You can recognize the tire pressure loss
warning by the
Run Flat Indicator Run Flat Indicator
Active Press 'OK' to Restart
Active Press 'OK' to Restart message
which appears in the Service
Servicemenu of the
multifunction display. Information on the
message display can be found in the
"Restarting the tire pressure loss warning
system" section (Y page 338).
Important safety notes The tire pressure warning system does not
warn you of an incorrectly set tire pressure.
Observe the notes on the recommended tire
pressure (Y
page 334).
The tire pressure loss warning does not
replace the need to regularly check the tire
pressure. An even loss of pressure on several
tires at the same time cannot be detected by
the tire pressure loss warning system.
The tire pressure monitor is not able to warn
you of a sudden loss of pressure, e.g. if the
tire is penetrated by a foreign object. In the Tire pressure
337Wheels and tires Z

event of a sudden loss of pressure, bring the
vehicle to a halt by braking carefully. Avoid
abrupt steering maneuvers.
The function of the tire pressure loss warning
system is limited or delayed if:
R snow chains are mounted on your vehicle's
tires.
R road conditions are wintry.
R you are driving on sand or gravel.
R you adopt a very sporty driving style
(cornering at high speeds or driving with
high rates of acceleration).
R you are towing a very heavy or large trailer.
R you are driving with a heavy load (in the
vehicle or on the roof).
Restarting the tire pressure loss
warning system Restart the tire pressure loss warning system
if you have:
R changed the tire pressure
R changed the wheels or tires
R mounted new wheels or tires
X Before restarting, make sure that the tire
pressures are set properly on all four tires
for the respective operating conditions.
The recommended tire pressure can be
found on the Tire and Loading Information
placard on the B-pillar on the driver's side
A tire pressure table is also affixed to the
fuel filler flap. The tire pressure loss
warning system can only give reliable
warnings if you have set the correct tire
pressure. If an incorrect tire pressure is set,
these incorrect values will be monitored.
X Observe the notes in the section on tire
pressures (Y page 334).
X Make sure that the SmartKey is in position
2(Y page 145) in the ignition lock.
X Press the =or; button on the
steering wheel to select the Service
Service
menu. X
Press the 9or: button on the
steering wheel to select the Tire Tire
Pressure
Pressure menu.
X Press the abutton.
The Run Flat Indicator Active
Run Flat Indicator Active
Press 'OK' to Restart
Press 'OK' to Restart message
appears in the multifunction display.
If you wish to confirm the restart:
X Press the abutton.
The Tire Pressure Now OK? Tire Pressure Now OK? message
appears in the multifunction display.
X Press the 9or: button to select
Yes
Yes.
X Press the abutton.
The Run Flat Indicator Restarted
Run Flat Indicator Restarted
message appears in the multifunction
display.
After a teach-in period, the tire pressure
loss warning system will monitor the set
tire pressures of all four tires.
If you wish to cancel the restart:
X Press the %button.
or
X If the Tire Pressure Now OK? Tire Pressure Now OK? message
appears, use the 9or: button to
select Cancel
Cancel .
X Press the abutton.
The tire pressure values stored at the last
restart will continue to be monitored. Tire pressure monitor
General notes If a tire pressure monitor is installed, the
vehicle's wheels have sensors that monitor
the tire pressures in all four tires. The tire
pressure monitor warns you if the pressure
drops in one or more of the tires. The tire
pressure monitor only functions if the
corresponding sensors are installed on all
wheels.
Information on tire pressures is displayed in
the multifunction display. After a few minutes338
Tire pressureWheels and tires