2009 MERCEDES-BENZ SLR spare wheel

272 OperationTires and wheelsThe TPMS only functions on wheels that
are equipped with the proper electronic
sensors. It monitors the tire inflation pres-
sure, as selected by the driver, in all four
tires. A warning is issued to alert you to a
decrease in pressure in one or more of the
tires.
Tire pressure inquiries are made using the
multifunction display. The present inflation
pressures are displayed only after a few
minutes’ travel time.
Switch on the ignition (
page 40).

Press buttonj or k on the mul-
tifunction steering wheel until the cur-
rent inflation pressures for each tire
appear in the multifunction display.
i
Possible differences between the readings
of a tire pressure gauge of an air hose, e.g. gas
station equipment, and the vehicle’s control
system can occur. Usually the readings issued by
the control system are more precise.
i
When the vehicle has been parked for longer
than 20 minutes, the message
Tire pressure
displayed after driving for a few
minutes.
appears in the multifunction display.
Warning!
G
It is the driver’s responsibility to calibrate
the TPMS on the recommended cold infla-
tion pressure. Underinflated tires affect the
ability to steer or brake the vehicle. You
might lose control over the vehicle.i
With a spare wheel mounted, the system
may still indicate the tire inflation pressure of the
removed road wheel for some minutes. If this
happens, keep in mind that the indicated value
where the spare wheel is mounted does not re-
flect the actual spare tire inflation pressure.
Warning!
G
The TPMS does not indicate a warning for
wrongly selected inflation pressures. Always
adjust tire inflation pressure according to
the Tire and Loading Information placard on
the driver’s door B-pillar or, if available, the
supplemental tire inflation pressure infor-
mation on the inside of the fuel filler flap.
The TPMS is not able to issue a warning due
to a sudden dramatic loss of pressure (e.g.
tire blowout caused by a foreign object). In
this case bring the vehicle to a halt by care-
fully applying the brakes and avoiding
abrupt steering maneuvers.

273 Operation
Tires and wheels
Warning!
G
Each tire, including the spare (if provided),
should be checked every other week when
cold and inflated to the inflation pressure
recommended by the vehicle manufacturer
on the Tire and Loading Information placard
or the tire inflation pressure label. If your ve-
hicle has tires of a different size than the
size indicated on the Tire and Loading Infor-
mation placard or the tire inflation pressure
label, you should determine the proper tire
inflation pressure for those tires.
As an added safety feature, your vehicle has
been equipped with a tire pressure monitor-
ing system (TPMS) that illuminates a low tire
pressure telltale when one or more of your
tires are significantly underinflated. Accord-
ingly, when the low tire pressure telltale illu-
minates, you should stop and check your
tires as soon as possible, and inflate them to
the proper pressure. Driving on a significant-
ly underinflated tire causes the tire to over-
heat and can lead to tire failure.
Underinflation also reduces fuel efficiency
and tire tread life, and may affect the vehi-
cle’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.
USA only:
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 com-
bined with the low tire pressure telltale.
When the system detects a malfunction, the
telltale will flash for approximately
one minute and then remain continuously
illuminated. This sequence will continue
upon subsequent vehicle start-ups 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 intend-
ed. TPMS malfunctions may occur for a vari-
ety of reasons, including the installation of
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 a condition causing the TPMS to malfunc-
tion develops, it may take up to 10 minutes for
the system to signal a malfunction using the
TPMS telltale flashing and illumination se-
quence.
The telltale extinguishes after a few minutes driv-
ing if the malfunction has been corrected.
i
Operating radio transmission equipment
(e.g. wireless headsets, two-way radios) in or
near the vehicle could cause the TPMS to mal-
function.

277 Operation
Tires and wheels
Tire size designation, load and speed
rating
1Tire width
2Aspect ratio in %
3Radial tire code
4Rim diameter
5Tire load rating
6Tire speed ratingGeneral:
Depending on the design standards used,
the tire size molded into the sidewall may
have no letter or a letter preceding the tire
size designation.
No letter preceding the size designation
(as illustrated above): Passenger car tire
based on European design standards.
Letter “P” preceding the size designation:
Passenger car tire based on U.S. design
standards.
Letter “LT” preceding the size designation:
Light Truck tire based on U.S. design
standards.
Letter “T” preceding the size designation:
Temporary spare tires which are high
pressure compact spares designed for
temporary emergency use only.
Tire width
The tire width1 (
page 277) indicates
the nominal tire width in mm. Aspect ratio
The aspect ratio2 (
page 277) is the
dimensional relationship between tire
section height and section width and is
expressed in percentage. The aspect ratio
is arrived at by dividing section height by
section width.
Tire code
The tire code3 (
page 277) indicates
the tire construction type. The “R” stands
for radial tire type. Letter “D” means diag-
onal or bias ply construction; letter “B”
means belted-bias ply construction.
At the tire manufacturer’s option, any tire
with a speed capability above 149 mph
(240 km/h) can include a “ZR” in the size
designation (for example: 245/40 ZR 18).
For additional information, see “Tire speed
rating” (
page 279).
i
For illustration purposes only. Actual data
on tires is specific to each vehicle and may vary
from data shown in above illustration.

287 Operation
Tires and wheels
DOT (D
epartment o
f T
ransportation)
A tire branding symbol which denotes the
tire meets requirements of the
U.S. Department of Transportation.
GAWR (G
ross A
xle W
eight R
ating)
The GAWR is the maximum permissible
axle weight. The gross vehicle weight on
each axle must never exceed the GAWR for
the front and rear axle indicated on the
certification label located on the driver’s
door A-pillar.
GVW (G
ross V
ehicle W
eight)
The GVW comprises the weight of the
vehicle including fuel, tools, spare wheel,
installed accessories, passengers and
cargo and, if applicable, trailer tongue
load. The GVW must never exceed the
GVWR indicated on the certification label
located on the driver’s door A-pillar.GVWR (G
ross V
ehicle W
eight R
ating)
This is the maximum permissible vehicle
weight of the fully loaded vehicle (weight of
the vehicle including all options, passen-
gers, fuel, and cargo and, if applicable,
trailer tongue load). It is indicated on
certification label located on the driver’s
door A-pillar.
Kilopascal (kPa)
The metric unit for air pressure. There are
6.9 kPa to 1 psi; another metric unit for air
pressure is bars. There are
100 kilopascals (kPa) to 1 bar.
Maximum load rating
The maximum load in kilograms and
pounds that can be carried by the tire.
Maximum loaded vehicle weight
The sum of curb weight, accessory weight,
total load limit and production options
weight.Maximum tire inflation pressure
This number is the greatest amount of air
pressure that should ever be put in the tire
under normal driving conditions.
Normal occupant weight
The number of occupants the vehicle is
designed to seat, multiplied by
68 kilograms (150 lb).
Occupant distribution
The distribution of occupants in a vehicle
at their designated seating positions.
Production options weight
The combined weight of those installed
regular production options weighing over
5 lb (2.3 kilograms) in excess of those
standard items which they replace, not
previously considered in curb weight or
accessory weight, including heavy duty
brakes, ride levelers, roof rack, heavy duty
battery, and special trim.

330 Practical hintsWhat to do if ...Left display
Right display
Possible cause/consequence
Possible solution
Tire Pressure
Monitor
Wheel Sensor Missing
One or more wheels without appropriate
wheel sensors mounted (e.g. spare wheel).
The respective tire is indicated by
---

instead of the tire inflation pressure in the
multifunction display.

Have the TPMS checked by an autho-
rized Mercedes-Benz Center.

Have appropriate wheel sensors in-
stalled by an authorized
Mercedes-Benz Center.
Tire Pressure
Monitor
Currently
Unavailable
The TPMS is unable to monitor the tire pres-
sure due to a nearby radio interference
source.
As soon as the causes for the malfunc-
tion are no longer present, the TPMS
automatically becomes active again
after a few minutes driving.
Warning!
G
Do not drive with a flat tire. A flat tire affects
the ability to steer or brake the vehicle. You
may lose control of the vehicle. Continued
driving with a flat tire will cause excessive
heat build-up and possibly a fire.