BMW 320i xDrive, Owner'S Manual

Page: 92 / 182

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Flat Tire Monitor*
The concept
As you drive, the Flat Tire Monitor
keeps track of pressure levels in all four
tires. The system alerts you whenever
the inflation pressure of a tire falls sig-
nificantly below the pressure of another
tire.
The system actually detects pressure
loss by monitoring differences in the
relative speeds of the four wheels. It
interprets variations outside specified
limits as severe pressure loss, and then
responds by generating a warning.
Functional requirements
In order for the Flat Tire Monitor to learn
the correct tire inflation pressure,
please do the following:
1. Check the tire inflation pressures in
all tires
2. Compare them with the tire inflation
pressure table on page 26 and cor-
rect them, if necessary
3. Initialize the system.
System limitations
The Flat Tire Monitor cannot pro-
vide you with advance warning of
sudden and severe tire damage caused
by external factors and does not detect
the balanced and very gradual pressure
loss that takes place in all four tires
over an extended period of time.
<
On the other hand, the following situa-
tions can lead to a delayed detection of
pressure loss and even to the system
not functioning:
>
Driving on snow-covered or slippery
roads
>
Performance-oriented driving: slip at
the drive wheels, high levels of lateral
acceleration
>
When driving with snow chains, false
warnings and undetected pressure
losses may occur
>
When driving with a space-saver
spare tire, the Flat Tire Monitor can-
not function.
Initializing the system
Each time you correct the pres-
sure in a tire, or change a wheel or
tire, reinitialize the system immediately
afterwards. This requires a bit of driv-
ing.
<
1. Before driving off, start the engine
but do not start driving
2. Press the button as long as you need
to until the yellow indicator lamp in
the instrument cluster lights up for a
few seconds
3. Drive off.
It takes a few minutes before the Flat
Tire Monitor can detect a flat tire and
issue a warning.