Overinflation
GWARNING
Tires with excessively high pressure can burst
because they are damaged more easily by
road debris, potholes etc. In addition, they
also suffer from irregular wear, which can
severely impair the braking properties and thedriving characteristics. There is a risk of an
accident.
Avoid tire pressures that are too high in all the
tires, including the spare wheel.
Overinflated tires may: R have an adverse effect on handling charac-
teristics
R wear quickly and unevenly
R be more susceptible to damage
R have an adverse effect on ride comfort
R increase the braking distance
Maximum tire pressures
Never exceed the maximum permissible tire
inflation pressure. Always observe the rec-
ommended tire pressure for your vehicle
when adjusting the tire pressure
(Y page 336).
:Example: maximum permissible tire pres-
sure
iThe actual values for tires are vehicle-
specific and may deviate from the values in
the illustration.
Checking the tire pressures
Important safety notes
Observe the "tire pressure information" sec-
tion ( Y page 336).
Information on air pressure for the tires on
your vehicle can be found:
R on the vehicle's Tire and Loading Informa-
tion placard on the B-pillar
R on the tire pressure label on the fuel filler
flap
R in the "Tire pressure information" section
Checking tire pressures manually
To determine and set the correct tire pres-
sure, proceed as follows: XRemove 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 with
the recommended values of the Tire and
Loading Information placard on the B-pillar
of the driver's side of your vehicle.
X If necessary, increase the tire pressure to
attain the recommended value
(Y page 336).
X If the tire pressure is too high, let out air. Do
so by pressing down the metal pin in the
valve. Then check the tire pressure again
using the tire pressure checker.
X Screw the valve cap onto the valve.
X Repeat these steps for the other tires.
Tire pressure monitor
General notes
If a tire pressure monitor is installed, the vehi-
cle's wheels have sensors that monitor the
tire pressures in all four tires. The tire pres-
sure monitor warns you if the pressure drops
in one or more of the tires. The tire pressure
Tire pressure339
Wheels and tires
Z
monitor only functions if the corresponding
sensors are installed on all wheels.
Information on tire pressures is displayed in
the multifunction display. After a few minutesof driving, the current tire pressure of each
tire is shown in the
Service menu of the mul-
tifunction display.
Example: current tire pressure display
For information on the message display, refer to the "Checking the tire pressure electroni-
cally" section ( Y page 341).
Important safety notes
GWARNING
Each tire, including the spare (if provided),
should be checked at least once a month
when cold and inflated to the pressure rec-
ommended by the vehicle manufacturer on
the Tire and Loading Information placard on
the driver's door B-pillar or the tire pressure
label on the inside of the fuel filler flap. If your
vehicle has tires of a different size than the
size indicated on the Tire and Loading Infor-
mation placard or the tire pressure label, you should determine the proper tire pressure for
those tires.
As an added safety feature, your vehicle has
been equipped with a tire pressure monitoring
system (TPMS) that illuminates a low tire pres-
sure telltale when one or more of your tires
are significantly underinflated. Accordingly,
when the low tire pressure telltale illuminates,
you should stop and check your tires as soon
as possible, and inflate them to the proper
pressure. Driving on a significantly underin-
flated tire causes the tire to overheat and can lead to tire failure. Underinflation also
reduces fuel efficiency and tire tread life, and
may affect the vehicle's handling and stop-
ping ability.
Please note that the TPMS is not a substitutefor proper tire maintenance, and it is the driv-
er'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.
Your vehicle has also been equipped with a
TPMS malfunction indicator to indicate if the
system is not operating properly. The TPMS
malfunction indicator is combined with the
low tire pressure telltale. When the system
detects a malfunction, the warning lamp will
flash for approximately a minute and then
remain 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 illuminated,
the system may not be able to detect or signal low tire pressure as intended. TPMS malfunc-
tions may occur for a variety of reasons,
including the installation of incompatible
replacement or alternate tires or wheels on
the vehicle that prevent the TPMS from func-
tioning properly. Always check the TPMS mal-
function 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 prop-
erly.
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 336). Note that the correct tire pres-
sure for the current operating 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 isaligned to the reference values taught-in.
Restart the tire pressure monitor after adjust-
ing the pressure of the cold tires
( Y page 342). The current pressures are
saved as new reference values. As a result, a
340Tire pressure
Wheels and tires
! Always use wheel bolts ; to mount the
collapsible spare wheel. Using other wheel
bolts to mount the collapsible spare wheel could damage the brake system.
Be sure to use the original-length wheel bolts
when re-mounting the original wheel after it
has been repaired.
! To prevent damage to the paintwork, hold
the wheel securely against the wheel hub
while screwing in the first wheel bolt.
X Clean the wheel and wheel hub contact
surfaces.
X Place the new wheel on the wheel hub and
push it on.
X Tighten the wheel bolts until they are fin-
ger-tight.
X Inflate the collapsible spare wheel
(Y page 367).
Only then lower the vehicle.
Lowering the vehicle
GWARNING
The wheels could work loose if the wheel nuts and bolts are not tightened to the specified
tightening torque. There is a risk of accident.
Have the tightening torque immediately
checked at a qualified specialist workshop
after a wheel is changed.
! Inflate the collapsible spare wheel using
the tire inflation compressor before lower-
ing the vehicle. The wheel rim could other-
wise be damaged.
X Place the ratchet wrench onto the hexagon
nut of the jack so that the letters AB are
visible.
X Turn the ratchet wrench until the vehicle is
once again standing firmly on the ground.
X Place the jack to one side.
X Tighten the wheel bolts evenly in a cross-
wise pattern in the sequence indicated ( :
to A ). The tightening torque must be
110 lb-ft (150 Nm) .
X Turn the jack back to its initial position and
store it together with the rest of the tire-
change tool kit in the cargo compartment.
X Transport the faulty wheel in the cargo
compartment.
X Check the tire pressure of the newly moun-
ted wheel and adjust it if necessary.
Observe the recommended tire pressure
( Y page 336).
For further information on stowing the col-
lapsible spare wheel, see ( Y page 367).
iWhen you are driving with the emergency
spare wheel mounted, the tire pressure
monitor cannot function reliably. Only
restart the tire pressure monitor when the
defective wheel has been replaced with a
new wheel. All wheels mounted must be
equipped with functioning sensors.
Mounting a wheel359
Wheels and tires
Z
Inflating the collapsible spare wheel
! Inflate the collapsible spare wheel using
the tire inflation compressor before lower-
ing the vehicle. The wheel rim could other-
wise be damaged.
X Pull connector ? and the air hose out of
the housing.
X Remove the cap from the valve on the col-
lapsible spare wheel.
X Screw union nut : on the air hose onto the
valve.
X Make sure on/off switch A of the tire
inflation compressor is set to 0.
X Insert plug ? into the socket of the ciga-
rette lighter ( Y page 284) or into a 12 V
power socket ( Y page 284) in your vehicle.
X Make sure that the SmartKey is in position
1 (Y page 149) in the ignition lock.
X Press on/off switch A on the tire inflation
compressor to I.
The tire inflation compressor is switched
on. The tire is inflated. The tire pressure is
shown on pressure gauge =.
! Do not operate the tire inflation compres-
sor for longer than eight minutes at a time
without a break. It may otherwise overheat.
The tire inflation compressor can be oper-
ated again once it has cooled down.
X Inflate the tire to the specified tire pres-
sure. The specified tire pressure is printed on the
yellow label of the emergency spare wheel.
X When the specified tire pressure has been
reached, press on/off switch A on the
electric air pump to 0.
The tire inflation compressor is switched
off.
X Turn the SmartKey to position 0 in the igni-
tion lock.
X If the tire pressure is higher than the speci-
fied pressure, press pressure release but-
ton ; until the correct tire pressure has
been reached.
X Unscrew union nut : on the air hose from
the valve.
X Screw the cap onto the valve of the col-
lapsible spare wheel again.
X Stow plug ? and the air hose in the lower
section of the blower housing.
X Stow the tire inflation compressor in the
vehicle.
Stowing a used collapsible spare wheel
Take the following steps to stow a used col-
lapsible spare wheel. Otherwise, the collaps-
ible spare wheel will not fit in the spare wheel
well. Mercedes-Benz recommends that you
have this work carried out at a qualified spe-
cialist workshop.
! Only place the collapsible spare wheel in
the vehicle when it is dry. Otherwise, mois-
ture may get into the vehicle.
X Remove the valve extractor from the vehi-
cle tool kit.
X Unscrew the valve cap from the valve.
X Unscrew the valve insert from the valve and
release the air.
iFully deflating the tires can take a few
minutes.
X Screw the valve insert back into the valve.
X Screw the valve cap back on.
Emergency spare wheel367
Wheels and tires
Z