213 Operation
Tires and wheels
4
The tire inflation pressure should be
checked regularly, i.e. at least each time
you refuel the vehicle. The preferred inter-
val for checking the tire inflation pressure,
however, is before each trip.
The inflation pressures specified either on
the tire and loading information placard on
the driver’s door B-pillar or on tire pressure
label below the driver’s seat on an outward
facing position of the mounting pillar are
always cold tire inflation pressures. Check
and adjust the tire inflation pressure when
the tires are cold. Cold tire inflation pres-
sure is defined as the tire pressure after
the vehicle has been parked for at least
3 hours or driven less than 1 mile (1.6 km)
at an ambient temperature of approxi-
mately 68 °F (20 °C).
The cold tire inflation pressure must not
exceed the maximum tire inflation pres-
sure molded into the tire side wall, see
"Tire labeling" (\2page 222).
If you check the tire inflation pressure
when the tires are warm (the vehicle has
been driven for several miles or sitting less than 3 hours), the reading will be higher
than the cold reading. This is normal. Do
not let air out to match the specified cold
tire inflation pressure. Otherwise, the tire
will be underinflated.Checking tire inflation pressure manu-
ally
Follow the steps below to achieve correct
tire inflation pressure:
\1Remove the cap from the valve on one
tire.
\1Firmly press a tire gauge onto the
valve.
\1Read the tire inflation pressure on the
tire gauge and compare it with the rec-
ommended tire inflation pressure on
the placard on the driver’s door B-pillar
or on the tire pressure label below the
driver’s seat. If necessary, add air to
achieve the recommended tire inflation
pressure.
\1Reattach the valve cap.Checking tire inflation pressure
Warning
G
Observe the recommended tire inflation
pressures.
Do not underinflate tires. Underinflated tires
wear excessively and/or unevenly, adverse-
ly affect handling and fuel economy, and are
more likely to fail from being overheated.
Do not overinflate tires. Overinflated tires
can adversely affect handling and ride com-
fort, wear unevenly, increase stopping dis-
tance, and result in sudden deflation
(blowout) because they are more likely to
become punctured or damaged by road de-
bris, potholes etc.
Do not overload the tires by exceeding the
specified load limit as indicated on the tire
and loading information placard on the driv-
er’s door B-pillar. Overloading the tires can
overheat them, possibly causing a blowout.
iIf you have overfilled the tire, release
tire inflation pressure by pushing the
metal stem of the valve with for exam-
ple a tip of a pen. Then recheck the tire
inflation pressure with the tire gauge.
214 OperationTires and wheels
4
\1Repeat this procedure for each tire.
Checking tire pressure electronically
with the Tire Pressure Monitoring Sys-
tem (TPMS)* (vehicles without steering
wheel buttons)
Vehicles without steering wheel buttons
are equipped with the Tire Pressure Moni-
toring System.The 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.
!
CAUTION
After inspecting or adjusting the tire in-
flation pressure, always reattach the
valve cap if equipped.
This will prevent moisture and dirt from
entering the valve stem, which could
damage the valve stem.
iUSA only:
The Tire Pressure Monitoring System
(TPMS) is equipped with a combination
low tire pressure/TPMS malfunction
telltale in the instrument cluster
(\2page 14). Depending on how the
telltale illuminates, it indicates a low
tire pressure condition or a malfunction
in the TPMS system itself:
\4If the telltale illuminates continu-
ously, one or more of your tires is
significantly underinflated. There is
no malfunction in the TPMS.
\4If the telltale flashes for 60 seconds
and then stays illuminated, the
TPMS system itself is not operating
properly.
iCanada only:
The Tire Pressure Monitoring System
(TPMS) is equipped with a low tire pres-
sure telltale in the instrument cluster
(\2page 14). If the telltale illuminates,
one or more of your tires is significantly
underinflated.Warning
G
The TPMS does not warn you against incor-
rectly selected tire inflation pressure and
does not warn you when the tire pressure is
not properly selected for the respective ve-
hicle load. It warns you only when the pres-
sure of one or more tires decreases
significantly below the reference inflation
\2\2
215 Operation
Tires and wheels
4
pressure which was stored at the time of
calibration of the TPMS after you inflated the
tires.
Always ensure that you re-calibrate the
TPMS after you inflated the tires to the rec-
ommended cold inflation pressure.
Always adjust tire inflation pressure accord-
ing to the tire and loading information plac-
ard on the driver’s door B-pillar.
Underinflated tires wear excessively and/or
unevenly, adversely affect handling and fuel
economy, and are more likely to fail from be-
ing overheated.
Overinflated tires can adversely affect han-
dling and ride comfort, wear unevenly, in-
crease stopping distance, and result in
sudden deflation (blowout) because they are
more likely to become punctured or dam-
aged by road debris, potholes etc.
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.
Warning
G
Each tire, including the spare (if provided),
should be checked monthly when cold and
inflated to the inflation pressure recom-
mended by the vehicle manufacturer on the
tire and loading information placard. (If your
vehicle has tires of a different size than the
size indicated on the vehicle placard or the
tire inflation pressure label, you should de-
termine 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 is 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 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.
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 1 minute
and then remain continuously illuminated.
This sequence will continue upon subse-
quent vehicle start-ups as long as the mal-
function exists. When the malfunction
indicator is illuminated, the system may not
be able to detect or signal low tire pressure
as intended.
\2\2
216 OperationTires and wheels
4
Reactivating the TPMS
The TPMS must be reactivated when you
have adjusted the tire inflation pressure to
a new level (e.g. because of different load
or driving conditions). The TPMS is then
recalibrated to the current tire inflation
pressures.\1Using the tire and loading information
placard on the driver’s door B-pillar
(\2page 206), make sure the tire infla-
tion pressure of all four tires is correct.
\1Switch on the ignition (\2page 67).
\1Press the 5menu button on the instru-
ment cluster until you see the
+CAL TPMS
message in the display.
TPMS malfunctions may occur for a variety
of reasons, including the installation of in-
compatible 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.iIf a condition causing the TPMS to mal-
function develops, it may take up to 10
minutes for the system to signal a mal-
function using the TPMS telltale flash-
ing and illumination sequence.
The telltale extinguishes after driving a
few minutes if the malfunction has
been corrected.
iOperating radio transmission equip-
ment (e.g. wireless headsets, two-way
radios) in or near the vehicle could
cause the TPMS to malfunctionWarning
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.
iReactivate the TPMS after adjusting
the tire inflation pressure to the infla-
tion pressure recommended for the ve-
hicle operating condition. Tire pressure
should only be adjusted on cold tires.
Observe the recommended tire infla-
tion pressure on the tire and loading in-
formation placard on the driver’s door
B-pillar (\2page 206).
217 Operation
Tires and wheels
4
\1Press the ,menu button on the instru-
ment cluster.
The following message is displayed:
OK TPMSThe tire pressure monitor activation
process has begun.
The tire pressures of the individual
wheels are stored as the new reference
values if they are determined to be
plausible for the tire pressure monitor.
If you wish to cancel the activation pro-
cess:
\1Press the .button or the 5menu button
on the instrument cluster.
The activation process is canceled au-
tomatically if 30 seconds elapse with
no input.Checking tire pressure electronically
with the Tire Pressure Monitoring Sys-
tem (TPMS)* (vehicles with steering
wheel buttons)
Vehicles with steering wheel buttons are
equipped with the Advanced Tire Pressure
Monitoring System.
The 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.
iUSA only:
The Tire Pressure Monitoring System
(TPMS) is equipped with a combination
low tire pressure/TPMS malfunction
telltale in the instrument cluster
(\2page 14). Depending on how the
telltale illuminates, it indicates a low
tire pressure condition or a malfunction
in the TPMS system itself:
\4If the telltale illuminates continu-
ously, one or more of your tires is
significantly underinflated. There is
no malfunction in the TPMS.
\4If the telltale flashes for 60 seconds
and then stays illuminated, the
TPMS system itself is not operating
properly.
iCanada only:
The Tire Pressure Monitoring System
(TPMS) is equipped with a low tire pres-
sure telltale in the instrument cluster
(\2page 14). If the telltale illuminates,
one or more of your tires is significantly
underinflated.
218 OperationTires and wheels
4
\1Switch on the ignition (\2page 67).
\1Press thej or kbutton until
the current inflation pressures for each
tire appear in the multifunction display.
iPossible differences between the read-
ings 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 con-
trol system are more precise.
54.32-2278-31
iWhen the message
Tire pres. dis-
played after driving for several
minutes
appears in the multifunction
display, the individual inflation pres-
sure values are matched with the tires.
The individual values are displayed af-
ter a few minutes' driving.
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.
iIf a spare wheel without wheel sensors
is mounted, the system may still indi-
cate the tire inflation pressure of the
removed wheel for some minutes. If
this happens, keep in mind that the in-
dicated value where the spare wheel is
mounted does not reflect the actual
spare tire inflation pressure.Warning
G
The TPMS does not warn you against incor-
rectly selected tire inflation pressure and
does not warn you when the tire pressure is
not properly selected for the respective ve-
hicle load. It warns you only when the pres-
sure of one or more tires decreases
significantly below the reference inflation
pressure which was stored at the time of
calibration of the TPMS after you inflated the
tires.
Always ensure that you recalibrate the
TPMS after you have inflated the tires to the
recommended cold inflation pressure.
\2\2
219 Operation
Tires and wheels
4
Always adjust the tire inflation pressure ac-
cording to the tire and loading information
placard on the driver’s door B-pillar.
Underinflated tires wear excessively and/or
unevenly, adversely affect handling and fuel
economy, and are more likely to fail from be-
ing overheated.
Overinflated tires can adversely affect han-
dling and ride comfort, wear unevenly, in-
crease stopping distance, and result in
sudden deflation (blowout) because they are
more likely to become punctured or dam-
aged by road debris, potholes etc.
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.
Warning
G
Each tire, including the spare (if provided),
should be checked monthly when cold and
inflated to the inflation pressure recom-
mended by the vehicle manufacturer on the
vehicle placard or the tire inflation pressure
label. (If your vehicle has tires of a different
size than the size indicated on the vehicle
placard or the tire inflation pressure label,
you should determine the proper tire infla-
tion 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 is 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 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.
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 1 minute
and then remain continuously illuminated.
This sequence will continue upon subse-
quent vehicle start-ups as long as the mal-
function exists. When the malfunction
indicator is illuminated, the system may not
be able to detect or signal low tire pressure
as intended.
\2\2
220 OperationTires and wheels
4
Reactivating Advanced TPMS
The TPMS must be reactivated when you
have adjusted the tire inflation pressure to
a new level (e.g. because of different load
or driving conditions). The TPMS is then
recalibrated to the current tire inflation
pressures.\1Using the tire and loading information
placard on the driver’s door B-pillar
(\2page 206), make sure the tire infla-
tion pressure of all four tires is correct.
\1Press buttonè orÿ on the mul-
tifunction steering wheel repeatedly
until the standard display menu ap-
pears in the multifunction display
(\2page 93).
TPMS malfunctions may occur for a variety
of reasons, including the installation of in-
compatible 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.iIf a condition causing the TPMS to mal-
function develops, it may take up to 10
minutes for the system to signal a mal-
function using the TPMS telltale flash-
ing and illumination sequence.
The telltale extinguishes after driving a
few minutes if the malfunction has
been corrected.
iOperating radio transmission equip-
ment (e.g. wireless headsets, two-way
radios) in or near the vehicle could
cause the TPMS to malfunctionWarning!
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.
iReactivate the TPMS after adjusting
the tire inflation pressure to the infla-
tion pressure recommended for the ve-
hicle operating condition. Tire pressure
should only be adjusted on cold tires.
Observe the recommended tire infla-
tion pressure on the tire and loading in-
formation placard on the driver’s door
B-pillar (\2page 206).