In this video I show you one way to repair a 2007 Chevy Truck with no oil pressure being displayed on the gauge and a P0523.

NOTICE:
Some how during the recording of this I lost some footage :( I mention that I change the sending unit / sensor and "the screen" Well the part of the video I am missing explains the "screen" This is a cylinder deactivation engine and below the oil pressure switch is a screen. Really simple to change. Just reach in with a 45 degree pick and slide it out once the switch is removed. Sorry :(