Opel ASTRA Owner's Manual page 260

258 Vehicle care
9 Warning
If the pressure is too low, this can
result in considerable tyre warm-
up and internal damage, leading to
tread separation and even to tyre
blow-out at high speeds.
If the tyre pressure shall be reduced
or increased on a vehicle with tyre
pressure monitoring system, switch
off ignition.
Tyre pressure monitoring
system
The tyre pressure monitoring system
checks the pressure of all four wheels
once a minute when vehicle speed
exceeds a certain limit.
All wheels must be equipped with
pressure sensors and the tyres must
have the prescribed pressure.
The current tyre pressures can be
shown in the Vehicle Information
Menu in the Driver Information
Centre.
The menu can be selected by the
buttons on the turn signal lever.
Press the MENU button to select the
Vehicle Information Menu.
Turn the adjuster wheel to select the
tyre pressure monitoring system.
System status and small pressure
differences are displayed by a
warning message with the
corresponding tyre flashing in the
Driver Information Centre.
Furthermore considerable pressure
differences between the tyres on one
axle are displayed by a warning
message in the Driver Information
Centre.
Major pressure differences are
indicated additionally by the control
indicator w.