
Checking tire pressures manually
To determine and set the correct tire
pressure, proceed as follows:
X Remove the valve cap of the tire that is to
be checked.
X Press the tire pressure gauge securely onto
the valve.
X Read the tire pressure and compare it with
the recommended value on the Tire and
Loading Information placard (Y page 547).
X If the tire pressure is too low, increase it to
the recommended value.
X If the tire pressure is too high, release air
by pressing down the metal pin in the valve.
Use the tip of a pen, for example .Then,
check the tire pressure again using the tire
pressure gauge.
X Screw the valve cap onto the valve.
X Repeatt hese steps for the other tires. Tire pressure loss warning system
(Canada only)
Important safety notes While the vehicle is in motion, the tire
pressure loss warning system monitors the
set tire pressure using the rotational speed of
the wheels. This enables the system to detect
significant pressure loss in a tire. If the speed
of rotation of a wheel changes as a result of
a loss of pressure, a corresponding warning
message will appearint he multifunction
display.
The tire pressure warning system does not
warn you of an incorrectly set tire pressure.
Observe the notes on the recommended tire
pressure (Y page 547).
The tire pressure loss warning does not
replace the need to regularly check the tire
pressure. An even loss of pressure on several
tires at the same time cannot be detected by
the tire pressure loss warning system.
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 function of the tire pressure loss warning
system is limited or delayed if:
R
snow chains are mounted on your vehicle's
tires.
R road conditions are wintry.
R you are driving on sand or gravel.
R you adopt a very sporty driving style
(cornering at high speeds or driving with
high rates of acceleration).
R you drive with a heavy load.
Restarting the tire pressure loss
warning system Restart the tire pressure loss warning system
if you have:
R
changed the tire pressure
R changed the wheels or tires
R mounted new wheels or tires
X Before restarting, make sure that the tire
pressures are set properly on all four tires
for the respective operating conditions.
The recommended tire pressures can be
found on the Tire and Loading Information
placard on the B-pillar on the driver's side
or the tire pressure table on the fuel filler
flap.
The tire pressure loss warning system can
only give reliable warnings if you have set
the correct tire pressure. If an incorrectt ire
pressure is set, these incorrect values will
be monitored.
X Observe the notes on tir epressure
(Y page 547).
X Make sure that the SmartKey is in position
2 in the ignitio nlock (Y page 155).
X Press the 000Bor0017 button on the
steering wheel to select the Serv. menu.Tire pressure
551Wheels and tires Z

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
(Y page 547). Note that the correct tire
pressure for the curren toperating situation
must first be taught-in to the tire pressure
monitor. If there is a substantial loss of
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 554). 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 547).
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.
If a tire pressure monitor is installed, the
vehicle's wheels have sensors that monitor
the tire pressures in all four tires. The tire
pressure monitor warns you if the pressure
drops in one or more of the tires. The tire
pressure monitor only functions if the correct
wheel electronics units are installed on each
wheel.
The tire pressure monitor has a yellow
warning lamp in the instrument cluster for
indicating pressure loss/malfunctions (USA)
or pressure loss (Canada). Whether the
warning lamp flashes or lights up indicates
whether a tire pressure is too low or the tire
pressure monitor is 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 USA only: if the warning lamp flashes for
around a minute and then remains lit
constantly, the tire pressure monitor is
malfunctioning.
Information on tire pressures is displayed in
the multifunction display. After a few minutes
of driving, the current tire pressure of each
tire is shown in the multifunction display.
USA only: if there is a malfunction with the
tire pressure monitor it can take more than
ten minutes until the malfunction is shown by
the tire pressure warning lamp flashing for
approximately one minute and then lighting
up continuously. 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
measured 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
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 in the ignition lock (Y page 155).
X Press the 000Bor0017 button on the
steering wheel to select the Serv. menu.
X Press the 0009or000A button to select
Tire Pressure .
X Press the 000Fbutton.
The curren ttire pressure of each tire is
shown in the multifunction display. Tire pressure
553Wheels and tires Z

If the vehicle has been parked for longer than
20 minutes, the
Tire pressure 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 message is shown instead
of the tire pressure display.T he tire pressures
are already being monitored.
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 in the pressure
display.
X If the Correct Tire Pressure message
appears in the multifunction display, 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. In most
cases, the tire pressure monitor will
automatically detect the new reference
values after you have changed the tire pressure. However, you can also define
reference values manually as described here.
X
Set the tire pressure to the value
recommended for the corresponding
driving situation on the Tire and Loading
Information placard on the B-pillar on the
driver's side (Y page 547).
Additional tire pressure values for different
loads can also be found on the tire pressure
table on the inside of the fuel filler flap
(Y page 547).
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 000Bor0017 on the steering wheel
to select the Serv. menu.
X Press the 0009or000A button to select
Tire Pressure .
X Press the 000Fbutton.
The multifunction display shows the
current tire pressure for the individual tires
or the Tire pressure will be displayed after driving a few
minutes message.
X Press the 000Abutton.
The Use Current Pressures as New Reference Values message appears in
the multifunction display.
If you wish to confirm the restart:
X Press the 000Fbutton.
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 001Fbutton.
The tire pressure values stored at the last
restart will continue to be monitored. 554
Tire pressureWheels and tires

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 halfoft he 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
installed 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. 0002
B-pillar, driver's side Maximum permissible gross vehicle
weight rating
X
Specification for maximum gross vehicle
weight 0002is listed in the Tire and Loading
Information placard: "The combined weight
of occupants and cargo should never
exceed XXX kilograms or XXX lbs."
The gross weight of all vehicle occupants,
load and luggage must not exceed the
specified value.
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.Y ou can find the valid
maximum permissible gross vehicle weight
rating for your vehicle on the Tire and
Loading Information placard. Loading the vehicle
555Wheels and tires Z