
pressure, the warning threshold for the
warning message is aligned to the reference
values taught-in .Restart the tire pressure
monitor after adjusting the pressure of the
cold tires (Y page 338). The current
pressures are saved as new reference values.
As a result, a warning message will appear if
the tire pressure drops significantly.
The tire pressure monitor does not warn you
of an incorrectly set tire pressure. Observe
the notes on the recommended tire pressure
(Y page 331).
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
event of a sudden loss of pressure, bring the
vehicle to a halt by braking carefully. Avoid
abrupt steering maneuvers.
The tire pressure monitor has a yellow
warning lamp in the instrument cluster for
indicating pressure loss or amalfunction.
Whether the warning lamp flashes or lights up
indicates whether a tire pressure is too low or
the tire pressure monito ris malfunctioning:
R if the warning lamp is lit continuously, the
tire pressure on one or more tires is
significantly too low. The tire pressure
monitor is not malfunctioning.
R if the warning lamp flashes for around a
minute and then remains lit constantly, the
tire pressure monitor is malfunctioning. G
WARNING
Each tire, including the spare (if provided),
should be checked at least once a month
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
pressure 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 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
pressure telltale when one or more of your
tires are significantly underinflated.
Accordingly, when the low tire pressure
telltale illuminates, you should stop and check
your tires as soon as possible, and inflate
them to the proper pressure. Driving on a
significantly underinflated 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 responsibility to maintain correct tire
pressure, even if underinflation has not
reached the level to trigger illumination of the
TPMS low tire pressure telltale.
Your vehicle has also been equipped with a
TPMS malfunction indicator to indicate if the
system is not operating properly. The TPMS
malfunction indicator is combined with the
low tire pressure telltale. When the system
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
vehicle is started as long as the malfunction
exists.
When the malfunction indicator is illuminated,
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
incompatible replacement or alternate tires
or wheels on the vehicle that prevent the
TPMS from functioning properly. Always
check the TPMS malfunction telltale after
replacing one or more tires or wheels on your
vehicle to ensure that the replacement or
alternate tires and wheels allow the TPMS to
continue to function properly.
i If the tire pressure monitor is
malfunctioning, it may take more than ten
minutes for the tire pressure warning lamp
to inform you of the malfunction by flashing Tire pressure
337Wheels and tires Z

for approximately one minute and then
remaining lit.
When the malfunction has been rectified,
the tire pressure warning lamp goes out
after a few minutes of driving.
i The tire pressure values indicated by the
on-board computer may differ from those
measured at a gas station with a pressure
gauge. The tire pressures show nby the on-
board computer refer to those measured at
sea level. At high altitudes, the tire pressure
values indicated by a pressur egauge are
higher than those shown by the on-board
computer. In this case, do not reduce the
tire pressures.
i The operatio nofthe tire pressure monitor
can be affected by interference from radio
transmitting equipment (e.g. radio
headphones, two-way radios) that may be
being operated in or near the vehicle.
Checking the tire pressure
electronically X
Make sure that the SmartKey is in position
2(Y page 141) in the ignition lock .
X Press the 0002or0005 button on the
steering wheel to select the Servicemenu.
X Press the 0003or0004 button to select
Tire Pressure .
X Press the 000Bbutton.
The current tire pressure of each tire is
shown in the multifunction display.
If the vehicle has been parked for over
20 minutes ,the Tire pressures will be
displayed after driving a few
minutes message appears.
After a teach-in process, the tire pressure
monitor automatically detects new wheels or
new sensors. As long as a clear allocation of
the tire pressure value to the individual
wheels is not possible, the Tire PressureMonitor Active display message is showninstead of the tire pressure display. The tire
pressures are already being monitored.
i
If a spare wheel/emergency spare wheel
is mounted, the system may continue to
show the tire pressure of the wheel that has
been removed for a few minutes. If this
occurs, note that the value displayed for
the position where the spare tire is
mounted is not the same as the spare
wheel/emergency spare wheel's current
tire pressure.
Tire pressure monitor warning
messages If the tire pressure monitor detects a
significant pressure loss on one or more tires,
a warning message is shown in the
multifunction display.
Awarning tone also
sounds and the tire pressure warning lamp
lights up in the instrumen tcluster.
Each tire that is affected by a significant loss
of pressure is highlighted with a color.
If the following message appears in the
multifunction display: Correct Tire Pressure:
X
Check the tire pressure on all four wheels
and correct it if necessary.
i If the wheel positions on the vehicle are
rotated, the tire pressures may be
displayed for the wrong positions for a
shor ttime. This is rectified after a few
minutes of driving, and the tire pressures
are displayed for the correc tpositions.
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
reference values for monitoring.
The tire pressure monitor must be restarted
when you set the tire pressure to a new value
(as a result of changed drive or load
characteristics, for example). The tire 338
Tire pressureWheels and tires

pressure monitor then monitors the new tire
pressure values.
Restart the tire pressure monitor after you
have set the tire pressure to the value
recommended for the desired driving
situation (Y page 331). Only correct tire
pressures on cold tires .Comply with the
recommended tire pressures on the Tire and
Loading Information placard the B-pillar on
the driver's side. Additional tire pressure
values for driving at high speeds or with heavy
loads can be found in the tire pressure table
on the inside of the fuel filler flap.
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 0002or0005 button on the
steering wheel to select the Servicemenu.
X Press the 0003or0004 button to select
Tire Pressure .
X Press the 000Bbutton.
The multifunction display shows the
current tire pressure for the individual tires
or the Tire pressures will be displayed after driving a few
minutes message.
X Press the 0004button.
The Use Current Pressures as New Reference Values message appears in
the multifunction display.
If you wish to confirm the restart:
X Press the 000Bbutton.
The Tire Press. Monitor Restarted message appears in the multifunction
display.
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 0007button.
The tire pressure values stored at the last
restart will continue to be monitored. Loading the vehicle
Instruction labels for tires and loads
G
WARNING
Overloaded tires can overheat, causing a
blowout. Overloaded tires can also impair the
steering and driving characteristics and lead
to brake failure. There is a risk of accident.
Observe the load rating of the tires. The load
rating must be at least half of the GAWR of
your vehicle. Never overload the tires by
exceeding the maximum load.
Two instruction labels on your vehicle show
the maximum possible load.
(1) The Tire and Loading Information placard is on the B-pillar on the driver's side. The
Tire and Loading Information placard
shows the maximum permissible number
of occupants and the maximum
permissible vehicle load. It also contains
details of the tire sizes and
corresponding pressures for tires
mounted at the factory.
(2) The vehicle identification plate is on the B-pillar on the driver's side. The vehicle
identification plate informs you of the
gross vehicle weight rating. It is made up
of the vehicle weight, all vehicle
occupants, the fuel and the cargo. You
can also find information about the
maximum gross axle weight rating on the
front and rear axle.
The maximum gross axle weight rating is
the maximum weight that can be carried
by one axle (front or rear axle). Never
exceed the maximum load or the
maximum gross axle weight rating for the
front or rear axle. Loading the vehicle
339Wheels and tires Z

reduce the braking distance on snow-covered
surfaces in comparison with summe
rtires.
Stopping distance, however, is still
considerably greater than when the road is
not covered with ice or snow. Take
appropriate care when driving.
! Avoid wheelspin .This can lead to damage
to the drive train. Temperature
G
WARNING
The temperature grade for this tire is
established for a tire that is properly inflated
and not overloaded. Excessive speed,
underinflation, or excessive loading, either
separately or in combination, can cause
excessive heat build-up and possible tire
failure.
The temperature grades are A(the highest),
B, and C. These represent the tire's
resistance to the generatio nofheat and its
ability to dissipate heat when tested under
controlled conditions on a specified indoor
laboratory test wheel. Sustained high
temperature can cause the material of the tire
to degenerate and reduce tire life, and
excessive temperature can lead to sudden
tire failure. The grade Ccorresponds to a level
of performance which all passenger car tires
must meet under the Federal Motor Vehicle
Safety Standard No. 109. Grades B and A
represent higher levels of performance on the
laboratory test wheel than the minimum
required by law. Tire labeling
Overview of tire labeling
The following markings are on the tire in
addition to the tire name (sales designation)
and the manufacturer's name: 0002
Uniform Tire Quality Grading Standard
(Ypage 349)
0003 DOT, Tire Identification Number
(Ypage 348)
0021 Maximum tire load (Y page 343)
0020 Maximum tire pressure (Y page 334)
001E Manufacturer
001F Tire material (Y page 349)
0011 Tire size designation, load-bearing
capacity and speed index (Y page 346)
0012 Load index (Y page 348)
0013 Tire name
i Tire data is vehicle-specific and may
deviate from the data in the example. Tire labeling
345Wheels and tires Z

Tire size designation
,load-bearing
capacity and speed rating 0002
Tire width
0003 Nominal aspec tratio in %
0021 Tire code
0020 Rim diameter
001E Load bearing index
001F Speed rating
i Tire data is vehicle-specific and may
deviate from the data in the example.
General: depending on the manufacturer's
standards, the size imprinted in the tire wall
may not contain any letters or may contain
one lette rthat precedes the size description.
If there is no letter preceding the size
description (as shown above): these are
passenger vehicle tires according to
European manufacturing standards.
If "P" precedes the size description: these are
passenger vehicle tires according to U.S.
manufacturing standards.
If "LT" precedes the size description: these
are light truck tires according to U.S.
manufacturing standards.
If "T" precedes the size description: these are
compact emergency spare wheels at high tire
pressure, to be used only temporarily in an
emergency.
Tire width: tire width0002shows the nominal
tire width in millimeters.
Height-width ratio: aspect ratio0003is the
size ratio between the tire height and tire
width and is shown in percent.T he aspectratio is calculated by dividing the tire width by
the tire height.
Tire code:
tire code0021specifies the tire type.
"R" represents radial tires; "D" represents
diagonal tires; "B" represents diagonal radial
tires.
Optionally, tires with a maximum speed of
over 149 mph (240 km/h) may have "ZR" in
the size description, depending on the
manufacturer (e.g. 245/40 ZR 18).
Rim diameter: rim diameter0020is the
diameter of the bead seat, not the diameter
of the rim flange. The rim diameter is
specified in inches (in).
Load-bearing index: load-bearing index001E
is a numerical code that specifies the
maximum load-bearing capacity of a tire.
Do not overload the tires by exceeding the
specified load limit. The maximum
permissible load can be found on the
vehicle's Tire and Loading Information
placard on the B-pillar on the driver's side
(Y page 339).
Example:
Load-bearing index 91 indicates a maximum
load of 1,356 lb (615 kg) that the tires can
bear. For further information on the maximum
tire load in kilograms and lbs, see
(Y page 343).
For further information on the load bearing
index, see "Load index" (Y page 348).
Speed rating: speed rating001Fspecifies the
approved maximum speed of the tire. G
WARNING
Exceeding the stated tire load-bearing
capacity and the approved maximum speed
could lead to tire damage or the tire bursting.
There is a risk of accident.
Therefore, only use tire types and sizes
approved for your vehicle model. Observe the
tire load rating and speed rating required for
your vehicle.
Regardless of the speed rating, always
observe the speed limits. Drive carefully and 346
Tire labelingWheels and tires

Load index
i
Tire data is vehicle-specific and may
deviate from the data in the example.
In addition to the load-bearing index, load
index 0002may be imprinted after the letters
that identify speed rating 001F(Ypage 346) on
the sidewall of the tire.
R If no specificatio nis given: no text (as in the
example above), represents astandard
load (SL) tire
R XL or Extra Load: represents a reinforced
tire
R Ligh tLoad: represents a light load tire
R C, D, E: represents a load range that
depends on the maximum load that the tire
can carry at a certain pressure DOT, Tire Identification Number (TIN)
U.S. tire regulations prescribe that every
manufacturer of new tires or retreader has to
imprint a TIN in or on the sidewall of each tire
produced. The TIN is a unique identification number. The
TIN enables tire manufacturers to inform
purchasers of recalls and other safety-
relevant matters. It makes it possible for the
purchaser to easily identify the affected tires.
The TIN is made up of manufacturer
identification code
0003, tire size0021, tire type
code 0020and manufacturing date 001E.
i Tire data is vehicle-specific and may
deviate from the data in the example.
DOT (Department of Transportation): tire
symbol 0002indicates that the tire complies
with the requirements of the U.S. Department
of Transportation.
Manufacturer identification code:
manufacturer identification code 0003provides
details on the tire manufacturer. New tires
have a code with two symbols. Retreaded
tires have a code with four symbols.
For further information about retreaded tires,
see (Y page 328).
Tire size: identifier0021describes the tire size.
Tire type code: tire type code0020can be used
by the manufacturer as acode to describe
specific characteristics of the tire.
Date of manufacture: date of manufacture
001E provides information about the age of a
tire. The first and second positions represent
the week of manufacture, starting with "01"
for the first calendar week. Positions three
and four represent the year of manufacture.
For example, a tire that is marked with
"3208", was manufactured in week 32 in
2008. 348
Tire labelingWheels and tires

Tire characteristics
i
Tire data is vehicle-specific and may
deviate fro mthe data in the example.
This information describes the type of tire
cord and the number of layers in
sidewall 0002and under tire tread 0003. Definition of terms for tires and
loading
Tire ply composition and material
used
Describes the number of plies or the number
of layers of rubber-coated fabric in the tire
tread and sidewall. These are made of steel,
nylon, polyester and other materials. Bar
Metric unit for tire pressure.
14.5038 pounds per square inch (psi) and
100 kilopascals (kPa) are the equivalent of
1 bar. DOT (Department of Transportation)
DOT marked tires fulfill the requirements of
the United States Department of
Transportation. Normal occupant weight
The number of occupants for which the
vehicle is designed multiplied by
68 kilograms (150 lbs). Uniform Tire Quality Grading
Standards
Au niform standard to grade the quality of
tires with regards to tread quality, tire traction
and temperature characteristics. Ratings are
determined by tire manufacturers using U.S.
government testing procedures. The ratings
are molded into the sidewall of the tire. Recommended tire pressure
The recommended tire pressure applies to
the tires mounted at the factory.
The Tire and Loading Informatio nplacard
contains the recommended tire pressures for
cold tires on a fully loaded vehicle and for the
maximum permissible vehicle speed.
The tire pressure table contains the
recommended pressures for cold tires for
various operating conditions, i.e. differing
load and speed conditions. Increased vehicle weight due to
optional equipment
This is the combined weight of all standard
and optional equipmen tavailable for the
vehicle, regardless of whethe ritis actually
installed on the vehicle or not. Rim
This is the part of the wheel on which the tire
is mounted. Definition of terms for tires and loading
349Wheels and tires Z

GAWR (Gross Axle Weight Rating)
The GAWR is the maximu mgross axle weight
rating. The actual load on an axle must never
exceed the gross axle weight rating. The
gross axle weight rating can be found on the
vehicle identification plate on the B-pillar on
the driver's side. Speed rating
The speed rating is part of the tire
identification. It specifies the speed range for
which the tire is approved. GTW (Gross Trailer Weight)
The GTW is the weight of a trailer including
the weight of the load, luggage, accessories
etc. on the trailer. GVW (Gross Vehicle Weight)
The gross vehicle weight includes the weight
of the vehicle including fuel, tools, the spare
wheel, accessories installed, occupants,
luggage and the drawbar noseweight, if
applicable.T he 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,
occupants, fuel, luggage and the drawbar
noseweight, if applicable). The gross vehicle
weight rating is specified on the vehicle
identification plate on the B-pillar on the
driver's side. Maximum loaded vehicle weight
The maximum weight is the sum of the curb
weight of the vehicle, the weight of the
accessories, the total load limit and the
weight of the optional equipment installed at
the factory. Kilopascal (kPa)
Metric unit for tire pressure. 6.9 kPa
corresponds to 1 psi. Another unit for tire
pressure is bar. 100 kilopascals (kPa) are the
equivalent of 1bar. Load index
In addition to the load-bearing index, the load
index may also be imprinted on the sidewall
of the tire. This specifie sthe load-bearing
capacity more precisely. Curb weight
The weight of a vehicle with standard
equipment including the maximum capacity
of fuel, oil and coolant. It also includes the air-
conditioning 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. 350
Definition of terms for tires and loadingWheels and tires