See also:

The concept
The tire inflation pressure is measured in the four mounted tires. The system notifies you if there is a significant loss of pressure in one or more tires. ...

Switching on/off manually
Press the button. On: the LED lights up. Off: the LED goes out. ...

Adjusting the volume
Turn the knob until the desired volume is selected. The setting is stored for the remote control currently in use. ...