2017 MERCEDES-BENZ S-Class CABRIOLET light

bility to maintain correct tire pressure, even ifunderinflation 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 thenremain 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
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.
It is the driver's responsibility to set the tire
pressure to that recommended for cold tires
which is suitable for the operating situation
(
Ypage 305). Note that the correct tire pressure
for the current operating situation must first be
taught-in to the tire pressure monitor. If a sub-
stantial loss of pressure occurs, the warning
threshold for the warning message is aligned to
the taught-in reference values. Restart the tire
pressure monitor after adjusting the pressure of
the cold tires (
Ypage 310). The current pres-
sures 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
(
Ypage 305).
The tire pressure monitor is n
ot 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
movements.
The tire pressure monitor has a yellow warning
lamp in the instrument cluster for indicating
pressure loss or a malfunction. Whether the
warning lamp flashes or lights up indicates
whether a tire pressure is too low or the tire
pressure monitor is malfunctioning:
Rif the warning lamp is lit continuously, the tire
pressure on one or more tires is significantly
too low. The tire pressure monitor is not mal-
functioning.
Rif the warning lamp flashes for around a
minute and then remains lit constantly, the
tire pressure monitor is malfunctioning.
In addition to the warning lamp, a message
appears in the multifunction display. Observe
the information on display messages
(
Ypage 226).
It may take up to ten minutes for a malfunction
of the tire pressure monitor to be indicated. A
malfunction will be indicated 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 a few minutes of
driving.
The tire pressure values indicated by the on-
board computer may differ from those meas-
ured at a gas station with a pressure gauge. The
tire pressures shown by the on-board computer
refer to those measured at sea level. At high
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 radio transmit-
ting equipment (e.g. radio headphones, two-way
radios) that may be being operated in or near the
vehicle.
Checking the tire pressure electroni-
cally
XMake sure that the SmartKey is in position 2
in the ignition lock (Ypage 124).
XUse ò on the steering wheel to call up the
list of menus.
XPress 9or: on the steering wheel to
select the Servicemenu.
XPress theabutton.
Tire pressure309
Wheels and tires
Z

XPress9or: to select Tire Pres‐sure.
XPress the abutton.
The current tire pressure of each tire is shown
in the multifunction display.
If the vehicle was parked for longer than
20 minutes, the following message appears:
Tire
pressurewillbedisplayedafterdriving a few minutes.
After a teach-in process, the tire pressure mon-
itor 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
PressureMonitorActivemessage 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. The yellow
tire pressure warning lamp then lights up.
RIf thePlease Correct Tire Pressuremessage appears 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.
RIf the Check Tiresmessage appears in the
multifunction display, the tire pressure in at
least one tire has dropped significantly. The
tires must be checked.
RIf the WarningTireMalfunctionmessage
appears in the multifunction display, the tire
pressure in at least one tire has dropped sud-
denly. The tires must be checked.
Observe the instructions and safety notes in the
display messages in the "Tires" section
(
Ypage 226).
If the wheel positions on the vehicle are rotated, the tire pressures may be displayed for the
wrong positions for a short time. This is rectified
after a few minutes of driving, and the tire pres-
sures 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 cur-
rently set tire pressure as the reference values for monitoring. In most cases, the tire pressure
monitor will automatically detect the new refer-
ence values after you have changed the tire
pressure. However, you can also set reference
values manually as described here. The tire
pressure monitor then monitors the new tire
pressure values.
XSet the tire pressure to the value recommen-
ded for the corresponding driving situation on
the Tire and Loading Information placard on
the driver's side B-pillar (
Ypage 305).
You can find more tire pressure values for
various operating conditions in the tire pres-
sure table inside the fuel filler flap
(
Ypage 305).
XMake sure that the tire pressure is correct on
all four wheels.
XMake sure that the SmartKey is in position 2
in the ignition lock.
XUse ò on the steering wheel to call up the
list of menus.
XPress 9or: on the steering wheel to
select the Servicemenu.
XPress theabutton.
XPress 9or: to select Tire Pres‐sure.
XPress the abutton.
The current tire pressure for each wheel or
the Tire pressure will be displayed
after driving a few minutesmessage
will be displayed in the multifunction display.
XPress the :button.
The UseCurrentPressuresasNewRef‐erenceValuesmessage appears in the mul-
tifunction display.
If you wish to confirm the restart:
XPress the abutton.
The TirePress.MonitorRestartedmes-
sage 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 pres-
sures are then accepted as reference values
and monitored.
If you wish to cancel the restart:
XPress the %button.
The tire pressure values stored at the last
restart will continue to be monitored.
310Tire pressure
Wheels and tires

tire load rating and speed rating required for
your vehicle.
General:depending on the manufacturer's
standards, the size imprinted in the tire wall may
not contain any letters or may contain one letter
that precedes the size description.
If there is no letter preceding the size descrip-
tion (as shown above): these are passenger
vehicle tires according to European manufac-
turing standards.
If "P" precedes the size description: these are
passenger vehicle tires according to U.S. man-
ufacturing standards.
If "LT" precedes the size description: these are
light truck tires according to U.S. manufacturing
standards.
If "T" precedes the size description: compact
emergency wheels with high tire pressure that
are only designed for temporary use in an emer- gency.
Tire width: tire width:shows the nominal tire
width in millimeters.
Height-width ratio: aspect ratio;is the size
ratio between the tire height and tire width and
is shown in percent. The aspect ratio is calcula-
ted by dividing the tire width by the tire height.
Tire code:tire code =specifies the tire type.
"R" represents radial tires; "D" represents diag- onal tires; "B" represents diagonal radial tires.
Optionally, tires with a maximum speed of over
149 mph (240 km/h ) ma
y have "ZR" in the size
description, depending on the manufacturer
(e.g. 245/40 ZR 18).
Rim diameter: rim diameter?is 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 indexAis 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 (
Ypage 311).
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 (
Ypage 317).
For further information on the load bearing
index, see "Load index" (
Ypage 317).
Speed rating: speed ratingBspecifies the
approved maximum speed of the tire.
iTire data is vehicle-specific and may deviate
from the data in the example.
Regardless of the speed rating, always observe
the speed limits. Drive carefully and adapt your
driving style to th
e traffic conditions.
Summer tires
IndexSpeed rating
Qup to 100 mph (160 km/h)
Rup to 106 mph (170 km/h)
Sup to 112 mph (180 km/h)
Tup to 118 mph (190 km/h)
Hup to 130 mph (210 km/h)
Vup to 149 mph (240 km/h)
Wup to 168 mph (270 km/h)
Yup to 186 mph (300 km/h)
ZR...Yup to 186 mph (300 km/h)
ZR...(..Y)over 186 mph (300 km/h)
ZRover 149 mph (240 km/h)
ROptionally, tires with a maximum speed of
over 149 mph (240 km/h) may have "ZR" in
the size description, depending on the man-
ufacturer (e.g. 245/40 ZR18).
The service specification is made up of load-
bearing index Aand speed rating B.
RIf the size description of your tire includes
"ZR" and there are no service specifications,
316All aboutwheels an d tires
Wheels and tires

ask the tire manufacturer in order to find out
the maximum speed.
If a service specification is available, the max-
imum speed is limited according to the speed
rating in the service specification. Example:
245/40 ZR18 97 Y. In this example, "97 Y" is
the service specification. The letter "Y" rep-
resents the speed rating. The maximum
speed of the tire is limited to 186 mph
(300 km/h).
RThe size description for all tires with maxi-
mum speeds of over 186 mph (300 km/h)
must include "ZR",andthe service specifica-
tion must be given in parentheses. Example:
275/40 ZR 18 (99 Y). Speed rating "(Y)" indi-
cates that the maximum speed of the tire is
over 186 mph (300 km/h). Ask the tire man-
ufacturer about the maximum speed.
All-weather tires and winter tires
IndexSpeed rating
Q M+S1up to 100 mph (160 km/h)
T M+S1up to 118 mph (190 km/h)
H M+S1up to 130 mph (210 km/h)
V M+S1up to 149 mph (240 km/h)
iNot all tires with the M+S marking provide
the driving characteristics of winter tires. In
addition to the M+S marking, winter tires also
have the isnowflake symbol on the tire
wall. Tires with this marking fulfill the require-
ments of the Rubber Manufacturers Associa-
tion (RMA) and the Rubber Association of
Canada (RAC) regarding the tire traction on
snow. They have been especially developed
for driving on snow.
An electronic speed limiter prevents your vehi-
cle from exceeding a speed of 130 mph
(210 km/h).
The speed rating of tires mounted at the factory
may be higher than the maximum speed that the
electronic speed limiter permits.
Make sure that your tires have the required
speed rating, e.g. when buying new tires. The
required speed rating for your vehicle can be
found in the "Tires" section (
Ypage 325). Further information about reading tire data can
be obtained from any qualified specialist work-
shop.
Load index
In addition to the load-bearing index, load
index
:may also be imprinted on the sidewall
of the tire. You will find this after the letter that
identifies the speed rating (
Ypage 315).
RIf no specification is given: no text (as in the
example above), represents a standard load
(SL) tire
RXL or Extra Load: represents a reinforced tire
RLight Load: represents a light load tire
RC, D, E: represents a load range that depends
on the maximum load that the tire can carry at
a certain pressure
iTire data is vehicle-specific and may deviate
from the data in the example.
Maximum load rating
Maximum tire load :is the maximum permis-
sible weight for which the tire is approved.
Do not overload the tires by exceeding the
specified load limit. The maximum permissible
1Or M+S ifor winter tires.
All about wheels and tires317
Wheels and tires
Z

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 whenthe tires are cold.
Cold tire pressure
The tires are cold:
Rif the vehicle has been parked with the tires
out of direct sunlight for at least three hours
and
Rif the vehicle has not been driven further than
1 mile (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.
Weight of optional extras
The combined weight of those optional extras
that weigh more than the replaced standard
parts and more than 5 lbs (2.3 kg). These
optional extras, such as high-performance
brakes, level control, a roof rack or a high-per-
formance battery, are not included in the curb
weight and the weight of the accessories.
TIN (Tire Identification Number)
This is a unique identifier which can be used by
a tire manufacturer to identify tires, for example
for a product recall, and thus identify the pur-
chasers. The TIN is made up of the manufactur- er's identity code, tire size, tire type code and
the manufacturing date.
Load bearing index
The load bearing index (also load index) is a code
that contains the maximum load bearing capa-
city of a tire.
Traction
Traction is the result of friction between the tires
and the road surface.
Treadwear indicators
Narrow bars (tread wear bars) that are distrib-
uted over the tire tread. If the tire tread is level
with the bars, the wear limit of áin (1.6 mm)
has been reached.
Occupant distribution
The distribution of occupants in a vehicle at their
designated seating positions.
Total load limit
Nominal load and luggage load plus 68 kg
(150 lbs) multiplied by the number of seats in
the vehicle.
Changing a wheel
Flat tire
The "Breakdown assistance" section
(Ypage 288 )contains information and notes on
how to deal with a flat tire. Information on driv-
ing with MOExtended tires in the event of a flat
tire can be found under "MOExtended tires (tires
with run-flat characteristics" (
Ypage 289).
Rotating the wheels
GWARNING
Interchanging the front and rear wheels may
severely impair the driving characteristics if
the wheels or tires have different dimensions. The wheel brakes or suspension components
may also be damaged. There is a risk of acci-
dent.
Rotate front and rear wheels only if the wheels and tires are of the same dimensions.
!On vehicles equipped with a tire pressure
monitor, electronic components are located
in the wheel.
Tire-mounting tools should not be used near
the valve. This could damage the electronic
components.
Only have tires changed at a qualified spe-
cialist workshop.
320Changing a wheel
Wheels and tires