Vauxhall ASTRA Owner's Manual page 226

Sensors for the tyre pressure monitoring
system can be retro-fitted. We recommend
that you consult your Vauxhall Authorised
Repairer.
When manually checking tyre pressure with
a pressure gauge, screw the adapter onto
the valve. Tyre pressure – see page 326.
The tyre pressure monitoring system valve
cores and sealing rings must be replaced
each time the tyres are changed. We
recommend that you consult your Vauxhall
Authorised Repairer.
The use of commercially available liquid
filled run-flat systems or repair kits can
impair the function of the system.
Vauxhall-approved systems can be used.
Radio transmitters (e.g. radio headphones,
walkie-talkies) operated in the area could
cause interference in the tyre pressure
monitoring system.
Drive control systems 221