Where does the oil pressure gauge get its reading from on a 2002 Envoy. There does not appear to be an oil pressure sensor only a pressure switch and an oil level temperature sensor?
The gauge cluster gets its information from the PCM (computer) It is a kind of fancy idiot light. It basically gives you readings based on signals that are in increments. None - low - medium - high etc. It cannot be considered an accurate gauge. It will tell you if you are without oil pressure and will tell you if it is higher or lower at any given point of driving.