MERCEDES-BENZ S-Class 2012 W221 Owner's Manual

1. This device may not cause harmful
interference, and
2. this device must accept any interference
received, including interference that may
cause undesired operation.
Any unauthorized modification to this
device could void the user’s authority to
operate the equipment.
Checking tire pressure electronicallyXMake sure that the SmartKey is in position
2 (Y page 303) in the ignition lock.XPress the = or ; button on the
steering wheel to select the Service
menu.XPress the 9 or : button to select
Tire Pressure .XPress the a button.
The current tire pressure for each wheel will
be displayed in the multifunction display.
If the vehicle has been parked for longer than
20 minutes, the Tire Pressures
Displayed After Driving A Few
Minutes message appears in the display.
After a teach-in period, the tire pressure
monitor automatically recognizes new wheels
or new sensors. If a clear allocation of the tire
pressure values to the individual wheels is not
possible, the Tire Pressure Monitor
Active message is shown instead 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. A warning tone also
sounds and the tire pressure warning lamp
lights up in the instrument cluster.
Each tire that is affected by a significant loss
of pressure is highlighted with a color.
If the Correct Tire Pressure message
appears in the multifunction display:
XCheck the tire pressure on all four wheels
and correct it if necessary.
i If the wheel positions on the vehicle are
interchanged, 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 pressures
are displayed for the correct positions.
Restarting the tire pressure monitor
GWARNING
It is the driver's responsibility to set the tire
pressure to the recommended cold tire
pressure. Underinflated tires affect the ability
to steer or brake the vehicle. You might lose
control over the vehicle.
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
pressure monitor then monitors the new tire
pressure values.
i Canada only: in most cases, the tire
pressure monitor recognizes the new
reference values automatically. However,
Tire pressure499Wheels and tiresZ

you can also define reference values
manually as described here.
Restart the tire pressure monitor after you
have set the tire pressure to the value
recommended for the desired driving
situation ( Y page 493). Only correct tire
pressures on cold tires. Comply with the
recommended tire pressures on the Tire and
Loading Information placard on 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.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.XPress the = or ; button on the
steering wheel to select the Service
menu.XPress the 9 or : button to select
Tire Pressure .XPress the a button.
The multifunction display shows the
current tire pressure of the individual tires
or the Tire Pressures Displayed
After Driving A Few Minutes
message.XPress the : button.
The Use Current Pressures As New
Reference Values message appears in
the multifunction display.
If you wish to confirm the restart:
XPress the a button.
The Tire Pressure 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:XPress the % button.
The tire pressure values stored at the last
restart will continue to be monitored.
Loading the vehicle
Instruction labels for tires and loads
GWARNING
Do not overload the tires by exceeding the
specified load limit as indicated on the Tire
and Loading Information placard on the
driver's door B-pillar. Overloading the tires
can overheat them, possibly causing a
blowout. Overloading the tires can also result
in handling or steering problems, or brake
failure.
Two instruction labels on your vehicle show
the maximum possible load.
(1)The Tire and Loading Information placard
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.500Loading the vehicleWheels and tires

:B-pillar, driver's side
Maximum permissible gross vehicle
weight rating
i The specifications shown on the Tire and
Loading Information placard in the
illustration are examples. The maximum
permissible gross vehicle weight rating is
vehicle-specific and may differ from that in
the illustration. You can find the valid
maximum permissible gross vehicle weight
rating for your vehicle on the Tire and
Loading Information placard.
XThe Tire and Loading Information placard
gives you details on maximum permissible
gross vehicle weight rating :: "The gross
weight of occupants and luggage must
never exceed XXX kilograms or XXX
pounds."
The gross weight of all vehicle occupants,
cargo, luggage and trailer load/noseweight (if
applicable) must not exceed the specified
value.
Number of seats
i The specifications shown on the Tire and
Loading Information placard in the
illustration are examples. The number of
seats is vehicle-specific and can differ from
the details shown. The number of seats in
your vehicle can be found on the Tire and
Loading Information placard.
Maximum number of seats : determines the
maximum number of occupants allowed to
travel in the vehicle. This information can be
found on the Tire and Loading Information
placard.
Determining the correct load limit
Step-by-step instructions
The following steps have been developed as
required of all manufacturers under Title 49,
Code of U.S. Federal Regulations, Part 575
pursuant to the "National Traffic and Motor
Vehicle Safety Act of 1966".
XStep 1: Locate the statement "The
combined weight of occupants and cargo
should never exceed XXX kg or XXX lbs." on
your vehicle’s Tire and Loading Information
placard.XStep 2: Determine the combined weight of
the driver and passengers that will be riding
in your vehicle.XStep 3: Subtract the combined weight of
the driver and passengers from XXX
kilograms or XXX lbs.Loading the vehicle501Wheels and tiresZ

XStep 4: The resulting figure equals the
available amount of cargo and luggage load
capacity. For example, if the "XXX" amount
equals 1400 lbs and there will be five
150 lbs passengers in your vehicle, the
amount of available cargo and luggage load
capacity is 650 lbs (1400 - 750 (5 x 150) =
650 lbs).X Step 5: Determine the combined weight of
luggage and cargo being loaded on the
vehicle. That weight may not safely exceed
the available cargo and luggage load
capacity calculated in step 4.XStep 6 (if applicable): If your vehicle will
be towing a trailer, load from your trailer
will be transferred to your vehicle. Consult
this manual to determine how this reduces
the available cargo and luggage load
capacity of your vehicle ( Y page 504).502Loading the vehicleWheels and tires

Example: step 1 to 3
The following table shows examples on how to calculate total and cargo load capacities with
varying seating configurations and number and size of occupants. The following examples use
a load limit of 1500 lbs. This is for illustration purposes only. Make sure you are using the
actual load limit for your vehicle stated on the vehicle’s Tire and Loading Information placard
( Y page 501).
Example 1Example 2Example 3Step 1Combined maximum
weight of occupants
and cargo (data from
the Tire and Loading
Information placard)1500 lbs
(680 kg)1500 lbs
(680 kg)1500 lbs
(680 kg)Example 1Example 2Example 3Step 2Number of people in
the vehicle (driver
and occupants)531Distribution of the
occupantsFront: 2
Rear: 3Front: 1
Rear: 2Front: 1Weight of the
occupantsOccupant 1:
150 lbs (68 kg)
Occupant 2:
180 lbs (82 kg)
Occupant 3:
160 lbs (73 kg)
Occupant 4:
140 lbs (63 kg)
Occupant 5:
120 lbs (54 kg)Occupant 1:
200 lbs (91 kg)
Occupant 2:
190 lbs (86 kg)
Occupant 3:
150 lbs (68 kg)Occupant 1:
150 lbs (68 kg)Gross weight of all
occupants750 lbs (340 kg)540 lbs (245 kg)150 lbs (68 kg)Loading the vehicle503Wheels and tiresZ

Example 1Example 2Example 3Step 3Permissible cargo
and trailer load/
noseweight
(maximum gross
vehicle weight rating
from the Tire and
Loading Information
placard minus the
gross weight of all
occupants)1500 lbs
(680 kg) -
750 lbs (340 kg)
= 750 lbs
(340 kg)1500 lbs
(680 kg) -
540 lbs (245 kg)
= 960 lbs
(435 kg)1500 lbs
(680 kg) -
150 lbs (68 kg) =
1350 lbs
(612 kg)
The higher the weight of all the occupants, the smaller the maximum load for luggage.
Further information can be found under "Towing a trailer" ( Y page 504).
Vehicle identification plate
Even if you have calculated the total load
carefully, you should still make sure that the
gross vehicle weight rating and the gross axle
weight rating are not exceeded. Details can
be found on the vehicle identification plate on
the B-pillar on the driver's side (Y page 500).
Gross vehicle weight: the gross weight of
the vehicle, all passengers, cargo and trailer
load/noseweight (if applicable) must not
exceed the permissible gross vehicle weight.
Gross axle weight rating: the maximum
permissible load that can be carried by one
axle (front or rear axle).
To ensure that your vehicle does not exceed
the maximum permissible values (gross
vehicle weight and maximum gross axle
weight rating), have your loaded vehicle
(including driver, occupants, cargo, and full
trailer load if applicable) weighed on a
suitable vehicle weighbridge.
Trailer load/noseweight
The trailer load/noseweight affects the gross
weight of the vehicle. If a trailer is attached,
the trailer load/noseweight is included in the
load along with occupants and luggage. The
trailer load/noseweight is usually
approximately 10% of the gross weight of the
trailer and its load.
Your Mercedes-Benz has been designed
primarily to carry passengers and their
luggage. Mercedes-Benz does not
recommend towing a trailer with your vehicle.
Maximum load rating
GWARNING
Do not overload the tires by exceeding the
specified load limit as indicated on the Tire
and Loading Information placard on the
driver's door B-pillar. Overloading the tires
can overheat them, possibly causing a
blowout. Overloading the tires can also result
in handling or steering problems, or brake
failure.
504Maximum load ratingWheels and tires

iThe actual values for tires are specific to
each vehicle and may deviate from the
values in the illustration.
Maximum tire load : is the maximum
permitted weight for which the tire is
approved.
Further information on tire loads
( Y page 506).
Uniform Tire Quality Grading
Standards
Overview of Tire Quality Grading
Standards
The Uniform Tire Quality Grading is a U.S.
Government requirement. Their purpose is to
provide drivers with consistent and reliable
information regarding tire performance. Tire
manufacturers are required to grade tires
using three performance factors: tread
wear :, tire traction ;, and temperature
resistance =. Although not a Government of
Canada requirement, all tires made for sale in
North America have these grades branded on
the sidewall.
i The actual values for tires are vehicle-
specific and may deviate from the values in
the illustration.
Where applicable, the tire grading
information can be found on the tire sidewall
between the tread shoulder and maximum
tire width.
For example:Tread wearTractionTemperature200AAA
All passenger car tires must conform to the
statutory safety requirements in addition to
these grades.
Tread wear
The tread wear grade is a comparative rating
based on the wear rate of the tire when tested
under controlled conditions on a specified
U.S. government course. For example, a tire
graded 150 would wear one and one-half
times as well on the government course as a
tire graded 100.
The relative performance of tires depends
upon the actual conditions of their use,
however, and may depart significantly from
the norm, due to variations in driving habits,
service practices and differences in road
characteristics and climate conditions.
Traction
GWARNING
The traction grade assigned to this tire is
based on straight-ahead braking traction
tests, and does not include acceleration,
cornering, hydroplaning, or peak traction
characteristics.
The traction grades, from highest to lowest,
are AA, A, B, and C. Those grades represent
Uniform Tire Quality Grading Standards505Wheels and tiresZ

the tire's ability to stop on a wet surface as
measured under controlled conditions on
specified government test surfaces of asphalt
and concrete. A tire marked C may have poor
traction performance.GWARNING
If ice has formed on the road, tire traction will
be substantially reduced. Under such weather
conditions, drive, steer and brake with
extreme caution.
The safe speed on a wet, snow covered or icy
road is always lower than on dry road
surfaces.
You should pay special attention to road
conditions when temperatures are around
the freezing point.
Mercedes-Benz recommends a minimum tire
tread depth of 1
/ 6 in (4 mm) for all four winter
tires ( Y page 492) to maintain normal driving
characteristics in winter. Winter tires can
reduce the braking distance on snow covered
surfaces in comparison to summer tires.
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
GWARNING
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 generation of heat 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 C corresponds 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
Tire labeling overview
The following markings are on the tire in
addition to the tire name (sales designation)
and the manufacturer's name:
:Uniform tire Quality Grading Standard
( Y page 511);DOT, Tire Identification Number
( Y page 509)=Maximum tire load ( Y page 504)?Maximum tire pressure ( Y page 496)AManufacturerBTire material ( Y page 510)506Tire labelingWheels and tires

CTire size designation, load-bearing
capacity and speed rating
( Y page 507)DLoad index ( Y page 509)ETire name
i
Tire data is vehicle-specific and may
deviate from the data in the example.
Tire size designation, load-bearing
capacity and speed rating
:Tire width;Nominal aspect ratio in %=Tire code?Rim diameterALoad bearing indexBSpeed 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 letter that 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 width : shows the nominal
tire width in millimeters.
Nominal aspect ratio: aspect ratio ; is the
size ratio between the tire height and the tire
width and is shown in percent. The aspect
ratio is calculated by dividing the tire width by
the tire height.
Tire code: tire code = specifies 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 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 index A
is a numerical code which specifies the
maximum load-bearing capacity of a tire.GWARNING
The tire load rating must always be at least
half of the GAWR of your vehicle. Otherwise,
sudden tire failure may be the result which
could cause an accident and/or serious injury
to you or others.
Always replace rims and tires with rims and
tires having the same specifications
(designation, manufacturer and type) as
shown on the original part.
GWARNING
Do not overload the tires by exceeding the
specified load limit as indicated on the Tire
and Loading Information placard on the
driver's door B-pillar. Overloading the tires
can overheat them, possibly causing a
blowout. Overloading the tires can also result
Tire labeling507Wheels and tiresZ

in handling or steering problems, or brake
failure.
Example:
The load bearing index 91 is equivalent to a
maximum load of 1356 lbs (615 kg) that the
tire can carry. For further information on the
maximum tire load in kilograms and pounds,
see ( Y page 504).
For further information on the load bearing
index, see Load index ( Y page 509).
Speed rating: speed rating B specifies the
approved maximum speed of the tire.GWARNING
Even when permitted by law, never operate a
vehicle at speeds greater than the maximum
speed rating of the tires.
Exceeding the maximum speed for which tires
are rated can lead to sudden tire failure,
causing loss of vehicle control and possibly
resulting in an accident and/or serious
personal injury and possible death, for you
and for others.
Regardless of the speed rating always
observe the speed limits. Drive carefully and
adapt your driving style to the traffic
conditions.
Summer tiresIndexSpeed ratingQUp 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)Summer tiresIndexSpeed ratingZR...YUp to 186 mph (300 km/h)ZR...(..Y)Above 186 mph (300 km/h)ZRAbove 149 mph (240 km/h)
R 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).
The service specifications consist of load
bearing index A and speed rating B.
R If the size description of your tire includes
"ZR" and there are no service
specifications, ask the tire manufacturer in
order to find out the maximum speed.
If a service specification is available, the
maximum speed is limited according to the
speed rating in the service specification.
Example: 245/40 ZR 18 97 Y. In this
example, "97 Y" is the service specification.
The letter "Y" represents the speed rating
and the maximum speed of the tire is
limited to 186 mph (300 km/h).
R Every tire that has a maximum speed above
186 mph (300 km/h) must have "ZR" in the
size description and the service
specification must be given in brackets.
Example: 275/40 ZR 18 (99 Y). The speed
rating "(Y)" shows that the maximum speed
of the tire is above 186 mph (300 km/h).
Ask the tire manufacturer to find out the
maximum speed.
All-weather tires and winter tiresIndexSpeed ratingQ M+S 29Up to 100 mph (160 km/h)T M+S29Up to 118 mph (190 km/h)29
Or M+S i for winter tires.508Tire labelingWheels and tires