In addition to the warning lamp ,am essage
appears in the multifunction display. Observe
the information on display messages
( Y
page 196).
It may take up to ten minutes for am alfunction
of the tire pressure monitor to be indicated .A
malfunction wil lbei ndicated by the tire pres-
sure warning lamp flashing for approximately
one minute and then remaining lit. When the
malfunction has been rectified, the tire pressure
warning lamp goes out after af ew minutes of
driving.
The tire pressure values indicated by the on-
board computer may differ from those meas-
ured at ag as station with ap ressure gauge. The
tire pressures shown by the on-board computer
refer to those measured at sea level .Ath igh
altitudes, the tire pressure values indicated by a
pressure gauge are higher than those shown by
the on-board computer. In this case, do not
reduce the tire pressures.
The operation of the tire pressure monitor can
be affected by interference from radi ot ransmit-
ting equipment (e.g. radi oh eadphones, two-way
radios) that may be being operated in or near the
vehicle.
Checking the tire pressure electroni-
cally X
Make sure that the SmartKey is in position 2
in the ignition lock ( Y
page 115).X
Press the Y or e button on the steering
wheel to select the Serv. menu.X
Press the c or d button to select
Tire Pressure .X
Press the v button.
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 pressure will be
displayed after driving af ew minutes
messag ea ppears.
After at each-in process, the tire pressure mon-
itor automatically detects new wheel sorn ew
sensors. As long as ac lear allocation of the tire
pressure valu etot he individual wheel sisn ot
possible, the Tire Pressure Monitor Active
display messag eiss hown instead of the tire
pressure display. The tire pressures are already
being monitored.
If an emergency spare wheel is mounted, the
system may continue to show the tire pressure of the wheel that has been removed for af ew
minutes. If this occurs, note that the valu ed is-
played for the positio nw here the spare wheel is
mounted is not the same as the current tire
pressure of the emergency spare wheel.
Tire pressure monitor warning mes-
sages If the tire pressure monitor detects ap ressure
loss in one or more tires, aw arning messag ei s
shown in the multifunction display. The yellow
tire pressure warning lamp then lights up. R
If the Please Correct Tire Pressure
messag ea ppears in the multifunction display,
the tire pressure in at least one tire is too low.
The tire pressure must be corrected when the
opportunity arises. R
If the Check Tires messag ea ppears in the
multifunction display, the tire pressure in at
least one tire has droppe ds ignificantly. The
tires must be checked. R
If the Warning Tire Malfunction message
appears in the multifunction display, the tire
pressure in at least one tire has droppe ds ud-
denly .T he tires must be checked.
Observe the instructions and safety notes in the
display messages in the "Tires" section
( Y
page 196).
If the wheel positions on the vehicle are rotated,
the tire pressures may be displaye df or the
wrong positions for as hort time. This is rectified
after af ew minutes of driving, and the tire pres-
sures are displaye df or the correct positions.
Restarting the tire pressure monitor When you restart the tire pressure monitor, all
existing warning messages are deleted and the
warning lamp sgoo ut. The monitor uses the cur-
rently set tire pressures as the reference values
for monitoring. In most cases, the tire pressure
monitor wil la utomatically detect the new refer-
ence values after you have changed the tire
pressure. However, you can also define refer-
ence values manually as describe dh ere. The tire
pressure monitor then monitors the new tire
pressure values. X
Set the tire pressure to the valu er ecommen-
ded for the corresponding driving situation on
the Tire and Loading Information placard on
the driver's side B-pilla r( Y
page 258).264
Tire pressure
Wheel sa nd tires
An electronic speed limite rp revents your vehi-
cle from exceeding as peed of 130 mph
(21 0k m/h).
The speed rating of tire sm ounted at the factory
ma ybeh ig he rt ha nt he maximu ms peed tha tt he
electronic speed limite rp er mits.
Make sure tha ty ou rt ire sh av et he required
speed rating ,e .g .w he nb uyin gn ew tires. The
required speed rating for your vehicl ec an be
found in the "tires "s ectio n( Y
page 278).
Further informatio na bout reading tire data can
be obtained from any qualified specialist work-
shop.
Load index
In additio ntot he load-bearing index, load
index C ma ya ls obei mprinte dont he sidewall
of the tire .Y ou will find thi sa fte rt he letter that
identifie st he speed rating ( Y
page 269).R
If no specification is given: no text (a sint he
exampl ea bo ve), represents as tandard load
(SL) tire R
XL or Extra Load: represents ar einforced tireR
Light Load: represents al ig ht load tireR
C, D, E: represents al oa dr an ge tha td epen ds
on the maximu ml oa dt ha tt he tire can carry at
ac ertain pressure
i Tire data is vehicle-specific and ma yd ev iate
from the data in the example. Maximum load rating
Maximu mt ire load C is the maximu mp er mis-
sibl ew eigh tf or which the tire is approved.
Do not overload the tire sbye xceeding the
specified load limit. The maximu mp er missible
load can be found on the vehicle's Tire and
Loading Informatio np la card on the B-pillar on
the driver's side ( Y
page 265).
i The actual values for tire sa re vehicle-spe-
cifi ca nd ma yd ev iate from the values in the
illustration.
DOT, Tire Identificatio nN umbe r( TIN)US tire regulations stipulate tha te very tire man-
ufacturer or retreader must imprint aT IN in or on
the sidewall of each tire produced.
The TIN is au niqu ei de ntificatio nn umber. The
TIN enables the tire manufacturer sorr etreaders
to inform purchaser sofr ecall sa nd othe rs af ety-
relevant matters .Itm ak es it possibl ef or the
purchaser to easily identify the affecte dt ires.
The TIN is made up of manufacturer identifica-
tio nc ode D ,t ire size
Speed rating The speed rating is part of the tire identification.
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, luggage and
the drawbar noseweight, if applicable. The gross
vehicle weight must not exceed the gross vehi-
cle weight rating GVWR as specified on the vehi-
cle 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 af ully 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.
Maximu ml oaded vehicle weightThe 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 1p si. Another unit for tire pressure is
bar. 100 kilopascals (kPa) are the equivalent of
1b ar.
Load index
In addition to the load-bearing index, the load
index may also be imprinted on the sidewal lo f
the tire. This specifies the load-bearing capacity
more precisely.
Curb weight
The weight of av ehicle with standard equipment
including the maximum capacity of fuel, oil and
coolant. It also includes the air-conditioning sys-
tem and optional equipment if these are instal-
led in the vehicle, but does not include passen-
gers or luggage. Maximu ml oad ratingThe maximum load rating is the maximum per-
missible weight in kilograms or lbs for which a
tire is approved.
Maximu mp ermissible tire pressureMaximum permissible tire pressure for one tire.
Maximu ml oad on one tireMaximum load on one tire. This is calculated by
dividing the maximum axle load of one axle by
two.
PSI (pounds per squar ei nch)As tandard unit of measure for tire pressure.
Aspect ratio Relationship between tire height and tire width
in percent.
Tire pressure This is pressure inside the tire applying an out-
ward force to each square inch of the tire's sur-
face. The tire pressure is specified in pounds per
square inch (psi), in kilopascal (kPa) or in bar.
The tire pressure should only be corrected when
the tires are cold.
Cold tire pressure The tires are cold: R
if the vehicle has been parked with the tires
out of direct sunlight for at least three hours
and R
if the vehicle has not been driven further than
1m ile (1.6 km)
Tread
The part of the tire that comes into contact with
the road.
Bead
The tire bead ensures that the tire sits securely
on the wheel. There are several steel wires in the
bead to prevent the tire from coming loose from
the wheel rim.
Sidewall
The part of the tire between the tread and the
bead.All about wheel sa nd tires 273
Wheels and tires Z