Tire pressure monitoring system
Function of the tire pressure monitoring sys‐
tem
The system checks the tire pressure and the tire
temperature of the tires installed on the vehicle
by means of a tire pressure sensor.
New tire pressure sensors, e.g. in winter tires,
are automatically taught-in during the first jour‐
ney they are used.
It is the driver's responsibility to set the tire pres‐
sure to the recommended cold tire pressure suit‐
able for the operating situation (
/
page 206).
Note that the correct tire pressure for the current
operating situation must first be taught-in to the
tire pressure monitoring system. If a substantial
loss of pressure occurs, the warning threshold for
the warning message is aligned to the taught-in
reference values. Restart the tire pressure moni‐
tor after adjusting to the cold tire pressure
(
/
page 209). The current pressures are saved
as new reference values. This will ensure that a
warning message will only appear if the tire pres‐
sure drops significantly.
The
h
warning lamp in the instrument cluster
displays a detected pressure loss or a malfunc‐
tion as follows:
R
If the
h
warning lamp is lit continuously,
the tire pressure on one or more tires is sig‐
nificantly too low. The tire pressure monitor is
not malfunctioning.
R
If the
h
warning lamp flashes for around a
minute and then remains lit constantly, the
tire pressure monitor is malfunctioning.
R
A message also appears in the instrument
cluster.
System limits
The system may be impaired or may not function
in the following situations:
R
The tire pressure has been set incorrectly.
R
There is a sudden pressure loss caused, for
example, by a foreign object penetrating the
tire.
R
There is a malfunction caused by another
radio signal source.
If the tire pressure monitor is malfunctioning, it
may take more than ten minutes for the
h
tire
pressure warning lamp to inform you of the mal‐
function. When the malfunction has been recti‐
fied, the
h
warning lamp goes out after you
have driven for a few minutes.
The tire pressure value indicated by the on-board
computer may differ from those measured at a
gas station using a pressure gauge.
The tire pressures shown by the on-board com‐
puter refer to those measured at sea level. At
high altitudes, the tire pressure value indicated
by a pressure gauge are higher than those shown
by the on-board computer. In this case, do not
reduce the tire pressure.
Checking the tire pressure electronically
(only vehicles with steering wheel buttons)
Requirements:
R
The ignition is switched on.
#
Press the
=
or
;
button to select
Service
.
#
Press the
a
button.
#
Press the
:
or
9
button to select
Tire
Pressure
.
#
Press the
a
button.
The display shows the current tire pressure of
each wheel.
If the vehicle was parked for longer than
20 minutes, the
Tire pressure will be displayed
after driving a few minutes
message appears in
the display.
Make sure to observe the following further rela‐
ted subject:
R
Notes on tire pressure (
/
page 206)
Restarting the tire pressure monitor
Requirements:
R
The ignition is switched on.
R
The recommended tire pressure is correctly
set for the respective operating condition on
each of the four wheels (
/
page 207).
Wheels and tires 209
