I have a problem with falling oil pressure in my Audi Convertible 2.3 liters. In the cold condition of the engine, my instrument shows 5 bar. After a short time, the pressure drops to 3 bar, later even to less than 1 bar. The control indicator next to the speedometer and tachometer also runs out in between and again. I changed the oil for safety reasons, but that’s not what it is. I have a few questions about this. mpe or oil pressure sensor and oil pressure switch? What is the difference between switch and sensor and which displays are controlled by the two?