Yellow is shown at the first indication of low tyre pressure, stop and check the tyre pressure as soon as possible.
Red indicates a much lower pressure than recommended, stop and rectify the tyre pressure immediately.
If a message for low tyre pressure is shown in the display:
Check the tyre pressure on the tyre in question.
Inflate the tyre(s) to the correct pressure.
Drive at least at 30 km/h for several minutes and check that the message disappears.