Hi,
Any of the things you mentioned can cause a false positive. Make sure the oil is clean and full. If it is, then take the connector off the oil pressure sensor and see if it is full of oil. These sensors can often times fail and allow oil pressure to be lost through the center of the sensor.
If you provide the engine size, I can get you testing info as well as directions, location of sensor, and so on.
Let me know.
Joe
Wednesday, April 8th, 2020 AT 7:18 PM