Instrument cluster bell/alarm/siren sounds while driving

[cparke]

Recently, every few days, randomly while driving the instrument cluster on this 98 Audi A4 V6 30V suddenly rings its bell/alarm for about 1-3 seconds. Not sure if anything is on display (my wife says no but I'm not convinced), but display is also heavily pixelated so it might be hard to recognize an icon in so little time. No fault codes recorded in Engine or Instrument Cluster. All dials normal. Engine is running normal.

What the hell could it be? What indicators control sounding of the instrument cluster alarm?

[MattzWarsteiner]

ABS, low coolant, high coolant temp, low oil press, low oil level are the ones I can think of.