2000 454 mag warning alarm going off , 40 psi oil pressure at a idle , water temp was good and coming out exhaust , drive oil bottle is full so what could be causing this ?

One of the senders are bad. All 3 senders are tied together, if only one goes bad, alarm will go off. My suggestion is, totally disconnect all of them and test each one of them, do a continuity test between the 2 wires on the drive oil, for the oil and the water temp, place one lead to ground and the other lead to stud of oil sender and same test for the water senders. If you have continuity on one of the senders, that will be the bad one. I believe them senders are naturally open, but when water temp is high or oil PSI is low or drive oil is low the sender closes the circuit (in which completes the ground for the alarm) and presto the damn alarm will say on. Hope this helps

I have experienced the same problem, but was low water pressure, water was still coming out of the exhaust. With no water pressure gauge it was difficult to diagnose.

Good info from the Captain.

It was the oil pressure sensor . Thanks for the help

I have experienced the same problem