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 tire pressure monitor has a yellow warn-
ing lamp in the instrument cluster for indicat-
ing pressure loss or a malfunction. Whether
the warning lamp flashes or lights up indi-
cates 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 signif-
icantly too low. The tire pressure monitor is
not malfunctioning. R
if 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
( Y
page 318).
It may take up to ten minutes for a malfunc-
tion of the tire pressure monitor to be indica-
ted. A malfunction will be indicated by the tire
pressure warning lamp flashing for approx-
imately 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 gage.
The tire pressures shown by the on-board
computer refer to those measured at sea
level. At high altitudes, the tire pressure val-
ues indicated by a pressure gage 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 trans-
mitting equipment (e.g. radio headphones,
two-way radios) that may be being operated
in or near the vehicle. Checking the tire pressure electroni-
cally X
Make sure that the SmartKey is in position
2 in the ignition lock ( Y
page 165).X
Press the Y or e button on the steer-
ing wheel to select the Service
menu.X
Press the c or d button to select
Tire Pressure
. X
Press the v button.
The current tire pressure of each tire is
shown in the multifunction display.
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 Pressure
Monitor Active display message is shown
instead of the tire pressure display. The tire
pressures are already being monitored.
i If an 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 posi-
tion where the spare wheel is mounted is
not the same as the current tire pressure of
the emergency spare wheel.
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 and the
yellow tire pressure monitor warning lamp
comes on. R
If the Please Correct Tire Pressure
message appears in the multifunction dis-
play, the tire pressure in at least one tire is414
Tire pressure
Wheels and tires
