There are 3 things that might set off your alarm: Low oil pressure as mentioned, low charging (alternator output) or high cooling water temperature.
The oil pressure light and low voltage light should be on (and the buzzer buzzing) when the key is on but the engine is not yet running. Under normal circumstances the high temp light would not be on at this time.
If all three indicator
lights do come on at once, it's likely a circuit/wiring fault. But you want to make sure that your cooling flow is normal, and your coolant level is normal (if FWC).
As you know, you can't count on always being able to sail to where you need to be.