fuel pressure MERCEDES-BENZ CLA-Class 2014 C117 User Guide

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.
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 spe- cialist 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, con-
tact 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 pres-
sure 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.
Use a suitable pressure gauge to check the
tire pressure. The outer appearance of a tire
does not permit any reliable conclusion about the tire pressure.
The tire temperature and pressure increase
when the vehicle is in motion. This is depend-
ent on the driving speed and the load.
Therefore, you should only correct tire pres-
sures 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 check-
ing the pressure of warm tires. 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 result-ing 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-pilla ron the driver's side
R in the tire pressure table on the inside of the
fuel filler flap Tire pressure
319Wheels and tires Z

Underinflated or overinflated tires
Underinflation G
WARNING
Tires with pressure that is too low can over-
heat and burst as a consequence. In addition, they also suffer from excessive and/or irreg-
ular wear, which can severely impair the brak- ing 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 charac-
teristics
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 charac-
teristics
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 the rec- ommended tire pressure for your vehicle
when adjusting the tire pressure
(Y
page 317). 0043
Example: maximum permissible tire pres-
sure
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" sec-
tion (Y page 317).
Information on air pressure for the tires on
your vehicle can be found:
R on the vehicle's Tire and Loading Informa-
tion 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 pres-
sure, 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 320
Tire pressureWheels and tires

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 317).
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 Monitor
General notes If a tire pressure monitor is installed, the vehi-
cle's wheels have sensors that monitor the
tire pressures in all four tires. The tire pres-
sure monitor warns you if the pressure drops
in one or more of the tires. The tire pressure
monitor only functions if the correct sensors
are installed on all wheels.
Information on tire pressures is displayed in
the multifunction display. After a few minutes of driving, the current tire pressure of each
tire is shown in the Service Servicemenu of the mul-
tifunction display. Example: current tire pressure display
For information on the message display, refer to the "Checking the tire pressure electroni-
cally" section (Y page 322).
Important safety notes G
WARNING
Each tire, including the spare (if provided),
should be checked at least once every two
weeks when cold and inflated to the pressure recommended by the vehicle manufacturer
on the Tire and Loading Information placard
on the driver's door B-pillar or the tire pres-
sure label on the inside of the fuel filler flap. If your vehicle has tires of a different size than
the size indicated on the Tire and Loading
Information placard or, if available, the tire
pressure label, you should determine the
proper tire pressure for those tires.
As an added safety feature, your vehicle has
been equipped with a tire pressure monitoring system (TPMS) that illuminates a low tire pres-
sure telltale when one or more of your tires
are significantly underinflated. Accordingly,
when the low tire pressure telltale lights up,
you should stop and check your tires as soon
as possible, and inflate them to the proper
pressure. Driving on a significantly underin-
flated tire causes the tire to overheat and can
lead to tire failure.
Underinflation also reduces fuel efficiency
and tire tread life, and may affect the vehicle's handling and stopping ability. Please note that
the TPMS is not a substitute for proper tire
maintenance, and it is the driver's responsi-
bility to maintain correct tire pressure, even if underinflation has not reached the level to
trigger illumination of the TPMS low tire pres-
sure telltale.
Your vehicle has also been equipped with a
TPMS malfunction indicator to indicate when
the system is not operating properly. The
TPMS malfunction indicator is combined with
the low tire pressure telltale. When the sys-
tem detects a malfunction, the warning lamp
will flash for approximately a minute and then remain continuously illuminated. This
sequence will be repeated every time the vehi-
cle is started as long as the malfunction
exists. When the malfunction indicator is illu- minated, the system may not be able to detect
or signal low tire pressure as intended.
TPMS malfunctions may occur for a variety of reasons, including the installation of incom-
patible replacement or alternate tires or
wheels on the vehicle that prevent the TPMS
from functioning properly. Always check the Tire pressure
321Wheels and tires
Z

Monitor Active
Monitor Active
message is shown instead
of the tire pressure display. The tire pressures
are already being monitored.
Tire pressure monitor warning mes-
sages If the tire pressure monitor detects a pressure
loss in one or more tires, a warning message
is shown in the multifunction display and the yellow tire pressure monitor warning light
comes on.
R If the Correct Tire Pressure
Correct Tire Pressure message
appears in the multifunction display, the
tire pressure in at least one tire is too low
and must be corrected at the next oppor-
tunity.
R If the Check Tire Pressure Soon Check Tire Pressure Soon mes-
sage appears in the multifunction display,
the tire pressure in one or more tires has
dropped significantly and the tires must be checked.
R If the Tire Pressure Warning Tire
Tire Pressure Warning Tire
Failure
Failure message appears in the multi-
function display, the tire pressure in one or
more tires has dropped suddenly and the
tires must be checked.
Observe the instructions and safety notes in
the display messages in the "Tires" section
(Y page 237).
i If the wheel positions on the vehicle are
rotated, the tire pressures may be dis-
played for the wrong positions for a short
time. This is rectified after a few minutes of driving, and the tire pressures are displayed
for the correct positions.
Restarting the tire pressure monitor When you restart the tire pressure monitor, all
existing warning messages are deleted and
the warning lamps go out. The monitor uses
the currently set tire pressures as the refer-
ence values for monitoring. In most cases, the
tire pressure monitor will automatically
detect the new reference values after you
have changed the tire pressure. However, you can also define reference values manually as
described here. The tire pressure monitor
then monitors the new tire pressure values.
X Set the tire pressure to the value recom-
mended for the corresponding driving sit-
uation on the Tire and Loading Information
placard on the driver's side
B-pillar (Y page 317).
Additional tire pressure values for different loads can also be found on the tire pressure
table on the inside of the fuel filler flap
(Y page 317).
X Make sure that the tire pressure is correct
on all four wheels.
X Make sure that the SmartKey is in position
2 in the ignition lock.
X Press the 0059or0065 button on the steer-
ing wheel to select the Service
Service menu.
X Press the 0063or0064 button to select
Tire Pressure Tire Pressure.
X Press the 0076button.
The multifunction display shows the cur-
rent tire pressure for each tire or the Tire Tire
pressure will be displayed after
pressure will be displayed after
driving a few minutes driving a few minutes message.
X Press the 0064button.
The multifunction display shows the Use
Use
Current
Current Pressures
Pressures as
asNew
New Reference
Reference
Values
Values message.
If you wish to confirm the restart:
X Press the 0076button.
The Tire Press. Monitor Restarted
Tire Press. Monitor Restarted
message appears in the multifunction dis-
play.
After driving for a few minutes, the system
checks whether the current tire pressures
are within the specified range. The new tire
pressures are then accepted as reference
values and monitored.
If you wish to cancel the restart: X Press the 0038button.
The tire pressure values stored at the last
restart will continue to be monitored. Tire pressure
323Wheels and tires Z

Speed rating
The speed rating is part of the tire identifica-
tion. It specifies the speed range for which the tire is approved. GVW (Gross Vehicle Weight)
The gross vehicle weight includes the weight
of the vehicle including fuel, tools, the spare
wheel, accessories installed, occupants, lug-
gage and the drawbar noseweight, if applica- ble. The gross vehicle weight must not exceed
the gross vehicle weight rating GVWR as
specified on the vehicle identification plate on the B-pillar on the driver's side. GVWR (Gross Vehicle Weight Rating)
The GVWR is the maximum permissible gross weight of a fully loaded vehicle (the weight of the vehicle including all accessories, occu-
pants, fuel, luggage and the drawbar nose-
weight, if applicable). The gross vehicle
weight rating is specified on the vehicle iden-
tification plate on the B-pillar on the driver's
side. Maximum loaded vehicle weight
The maximum weight is the sum of:
R the curb weight of the vehicle
R the weight of the accessories
R the load limit
R the weight of the factory installed optional
equipment Kilopascal (kPa)
Metric unit for tire pressure. 6.9 kPa corre-
sponds to 1 psi. Another unit for tire pressure
is bar. 100 kilopascal (kPa) is the equivalent
of 1 bar. Load index
In addition to the load-bearing index, the load
index may also be imprinted on the sidewall of the tire. This specifies the load-bearing capa- city more precisely. Curb weight
The weight of a vehicle with standard equip-
ment including the maximum capacity of fuel, oil and coolant. It also includes the air-condi- tioning system and optional equipment if
these are installed in the vehicle, but does not
include passengers or luggage. Maximum load rating
The maximum load rating in kilograms or
pounds is the maximum weight for which a
tire is approved. Maximum permissible tire pressure
Maximum permissible tire pressure for one
tire. Maximum load on one tire
Maximum load on one tire. This is calculated
by dividing the maximum axle load of one axle by two. PSI (pounds per square inch)
A standard unit of measure for tire pressure. Aspect ratio
Relationship between tire height and tire
width in percent. 334
Definition of terms for tires and loadingWheels and tires

X
Clean the wheel and wheel hub contact
surfaces.
X Place the new wheel on the wheel hub and
push it on.
X Tighten the wheel bolts until they are fin-
ger-tight.
Lowering the vehicle G
WARNING
The wheels could work loose if the wheel nuts and bolts are not tightened to the specified
tightening torque. There is a risk of accident.
Have the tightening torque immediately
checked at a qualified specialist workshop
after a wheel is changed. X
Place the ratchet wrench onto the hexagon
nut of the jack so that the letters ABare
visible.
X Turn the ratchet wrench until the vehicle is
once again standing firmly on the ground.
X Place the jack to one side. X
Tighten the wheel bolts evenly in a cross-
wise pattern in the sequence indicated ( 0043
to 0083). The specified tightening torque is
96 lb-ft (130 Nm ).
X Turn the jack back to its initial position.
X Stow the jack and the rest of the vehicle
tools in the vehicle again.
X AMG vehicles and vehicles with AMG
equipment: insert the cover into the outer
sill.
X Check the tire pressure of the newly moun-
ted wheel and adjust it if necessary.
Observe the recommended tire pressure
(Y page 317).
i Vehicles with tire pressure monitor: all
wheels mounted must be equipped with
functioning sensors. Wheel and tire combinations
General notes
! For safety reasons, Mercedes-Benz rec-
ommends that you only use tires and
wheels which have been approved by
Mercedes-Benz specifically for your vehi-
cle.
These tires have been specially adapted for
use with the control systems, such as ABS
or ESP ®
, and are marked as follows:
R MO = Mercedes-Benz Original
R MOE = Mercedes-Benz Original Extended
(tires featuring run-flat characteristics)
R MO1 = Mercedes-Benz Original (only cer-
tain AMG tires)
Mercedes-Benz Original Extended tires
may only be used on wheels that have been
specifically approved by Mercedes-Benz.
Only use tires, wheels or accessories tes-
ted and approved by Mercedes-Benz. Cer-
tain characteristics, e.g. handling, vehicle
noise emissions or fuel consumption, may
otherwise be adversely affected. In addi-
tion, when driving with a load, tire dimen-
sion variations could cause the tires to 340
Wheel and tire combinationsWheels and ti
res

come into contact with the bodywork and
axle components. This could result in dam- age to the tires or the vehicle.
Mercedes-Benz accepts no liability for
damage resulting from the use of tires,
wheels or accessories other than those tes-
ted and approved.
Information on tires, wheels and approved
combinations can be obtained from any
qualified specialist workshop.
! Retreaded tires are neither tested nor rec-
ommended by Mercedes-Benz, since pre-
vious damage cannot always be detected
on retreaded tires. As a result, Mercedes-
Benz cannot guarantee vehicle safety if
retreaded tires are mounted. Do not mount used tires if you have no information about
their previous usage.
Overview of abbreviations used in the follow-
ing tire tables:
R BA: both axles
R FA: front axle
R RA: rear axle
The recommended pressures for various
operating conditions can be found:
R on the Tire and Loading Information placard
with the recommended tire pressures on
the B-pillar on the driver's side
R in the tire pressure table on the inside of the
fuel filler flap
Observe the notes on recommended tire
pressures under various operating conditions (Y page 317).
Check tire pressures regularly, and only when the tires are cold. Comply with the mainte-
nance recommendations of the tire manufac-
turer in the vehicle document wallet.
Notes on the vehicle equipment – always
equip the vehicle with:
R tires of the same size on a given axle (left/
right)
R the same type of tires at a given time (sum-
mer tires, winter tires, MOExtended tires) Exception: it is permissible to install a dif-
ferent type or make in the event of a flat
tire. Observe the "MOExtended tires (tires
with run-flat characteristics" section
(Y
page 297).
i Vehicles equipped with MOExtended tires
are not equipped with a TIREFIT kit at the
factory. It is therefore recommended that
you additionally equip your vehicle with a
TIREFIT kit if you mount tires that do not
feature run-flat properties, e.g. winter tires. A TIREFIT kit can be obtained from a quali- fied specialist workshop.
i The following pages contain information
on approved wheel rim and tire sizes for
equipping your vehicle with winter tires.
Winter tires are not available at the factory as standard equipment or optional extras.
If you want to equip your vehicle with
approved winter tires, it may be necessary
to obtain wheel rims in the corresponding
size. The size of the approved winter tires
may differ from the standard tires. This is
dependent on the model and the equip-
ment installed at the factory.
The tires and wheel rims, as well as further
information, can be obtained at a qualified
specialist workshop.
i Not all wheel and tire combinations are
available at the factory for all countries. Wheel and tire combinations
341Wheels and tires Z