On the drive home after buying my 2001 (39K miles)the oil pressure light came on in the middle of hwy 5. The oil level was low so added 1 quart which brought it slightly above the limit & the light went out. Looks like the oil pressure sender is pretty sensitive and thereforeit's a good idea to keep the oil level correct or you risk low oil pressure and, as cincyTT says, a seized engine. The factory does things like oil level marks for a reason.