Getting a "Low Oil Pressure" message on the dash board.."Turn off engine" any ideas of what the problem might be?

Just because the message says low oil pressure, it does not have to mean that you actually do have low oil pressure. The sending unit could be defective, which could give you a false message. It is quite rare for an oil pump to fail. Check your oil level on your dipstick. If you are down a couple of quarts of oil, the oil pressure could be low.

Low pressure when at idle, after the engine has warmed up and the oil has thinned, indicates that the oil pump is worn and needs to be replaced.

MAY---May-be you really have low oil pressure.. The way this sensor works is when you turn off the engine it closes to ground.. and when you start the engine.. the oil pressure opens it and the light goes out.. SO.. if the wire going to it is grounded out somewhere between the sensor and the dash board the light will stay on.. 3 choices.. 1. bad sensor (even though you replaced it) 2. wire is shorted to ground.. remove wire from sensor while engine is running.. light should go out. 3. you actually have really low oil presure. next.. after you have exuasted #1-2. you can remove sensor and install a real oil pressure guage and see what the pressure really is.. If you have very low or no oil pressure..1. Check oil level.(probably should have done this first) 2.pull oil pan and replace oil pump.. while you are there check a main bearing and a rod bearing for wear.. worn out bearings will cause low oil pressure. If you have good oil pressure install the pressure guage permanetly and forget about light.

internal engine failure

DTC P0521: Engine Oil Pressure (EOP) Sensor Performance

The engine oil pressure (EOP) sensor changes voltage based on the engine oil pressure. The EOP sensor is a 3-wire sensor comprising of the signal circuit, the low reference circuit and the 5-volt reference circuit. The engine control module (ECM) supplies 5 volts to the EOP sensor via the 5-volt reference circuit and provides ground via the EOP low reference circuit. The ECM monitors the signal circuit of the EOP sensor to determine the EOP sensor voltage is within the normal operating range of approximately 1-4 volts. When the engine oil pressure is high, the EOP sensor voltage is high and the ECM senses a high signal voltage. When the engine oil pressure is low, the EOP sensor voltage is low and the ECM senses a low signal voltage. The ECM sends the EOP information to the instrument panel cluster (IPC) via GMLAN serial data message.

Conditions for Setting the DTC
P0521
The ECM detects that the difference between the predicted oil pressure and the actual oil pressure is either less than 47 kPa (6.8 psi) or greater than 50 kPa (7.3 psi).

Your best bet ,take it to a qualified repair shop that has the proper diagnostic testing equipment to diagnose this.

I have a keyless fob and am getting the same message. Any ideas how to get the message to turn off?

You have to prime the oil pump using a special tool... it goes down the distributer hole yes, you have to remove it.. make sure you mark it carefully!!!!!!!!!..
350 Chevy oil pump prime
Priming the oil system on new small block Chevy
Oil pump installation 350 chevy
Priming the oil pump
oil pump priming tool direction of rotation Third Generation Body Message...

Check your oil. If it is low, top it off and see if the light goes out. If your oil is full, have your oil pressure checked.

as long as oil pressure is in specs its ok but pump maybe getting weak,pump may not be holding prime!!! :)

Most important thing you need to do is to establish the actual oil pressure. put a mechanical gauge on the engine and read real oil pressure. If pressure is low (min is 15psi, I prefer to see at least 20 at idle) there is an internal problem...bearings etc. If pressure is good, sending unit has failed...replace it. I would not drive it 'till the oil pressure is verified as being safe. You might get lucky and someone just forgot to plug in the sending unit, but it must be checked!!!
good luck