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 tyre pressure monitor after
adjusting to the cold tyre pressure
(Y page 360). The current pressures are
saved as new reference values. This will
ensure that a warning message will only
appear if the tyre pressure drops significantly.
The tyre pressure monitor does not warn you of an incorrectly set tyre pressure. Observe
the notes on the recommended tyre pressure
(Y page 356).
The tyre pressure monitor is not able to warn you of a sudden loss of pressure, e.g. if the
tyre 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 manoeuvres.
The tyre pressure monitor has a yellow warn-
ing lamp in the instrument cluster for indicat-
ing a pressure loss or malfunction. Depending on how the warning lamp flashes or lights up,
a tyre pressure that is too low or a malfunc-
tion in the tyre pressure monitor is indicated:
R if the warning lamp is lit continuously, the
tyre pressure on one or more tyres is sig-
nificantly too low. The tyre pressure moni-
tor is not malfunctioning.
R if the warning lamp flashes for around a
minute and then remains lit constantly, the
tyre 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 276).
It may take up to ten minutes for a malfunc-
tion of the tyre pressure monitor to be indi-
cated. A malfunction will be indicated by the
tyre pressure warning lamp flashing for
approximately one minute and then remain-
ing lit. When the fault has been rectified, the
tyre pressure warning lamp goes out after you
have driven for a few minutes.
The tyre pressure values indicated by the on- board computer may differ from those meas- ured at a filling station using a pressure
gauge. The tyre pressures shown by the on-
board computer refer to those measured at
sea level. At high altitudes, the tyre pressure
values indicated by a pressure gauge are
higher than those shown by the on-board
computer. In this case, do not reduce the tyre
pressures.
The operation of the tyre pressure monitor
can be affected by interference from radio
transmitting equipment (e.g. radio head-
phones, two-way radios) that may be being
operated in or near the vehicle.
Checking the tyre pressure electroni-
cally X
Make sure that the key is in position 2in the
ignition lock (Y page 159).
X Press =or; on the steering wheel
to select the Serv.
Serv.menu.
X Press the 9or: button to select
Tyre pressure Tyre pressure.
X Press the abutton.
The current tyre pressure for each wheel
will be displayed in the multifunction dis-
play.
If the vehicle was parked for longer than
20 minutes, the Tyre Tyrepressures
pressures will
willbe
be
displayed after a few minutes of
displayed after a few minutes of
driving driving message is shown.
After a teach-in period, the tyre pressure
monitor automatically detects new wheels or
new sensors. As long as a clear allocation of
the tyre pressure values to the individual
wheels is not possible, the Tyre pressure Tyre pressure
monitor active
monitor active message is shown instead
of the tyre pressure display. The tyre pres-
sures are already being monitored.
If an emergency spare wheel is fitted, for a
few minutes the system may continue to
show the tyre pressure of the wheel that has been removed. If this occurs, note that the
value displayed for the position where the
spare wheel is fitted is not the same as the
current tyre pressure of the emergency spare wheel. Tyre pressure
359Wheels and tyres Z
