If you problem is that the gauge shows oil pressure with the engine off, you have a gauge or sending unit failure.
The oil gauge shows the oil's temperature. The oil pressure gauge monitors the oil pressure for your viewing pleasure.
Your check gauge light comes on if : your coolant temperature guage shows the temperature is high your oil pressure gauge shows the oil pressure is low or your fuel gauge shows the fuel tank is near empty
I feel sure you have checked to see that the engine has oil in it. You need to install an external oil pressure gauge, the mechanical type and check for pressure. If it shows that you have oil pressure then your sending unit is defective.
no if the oil pressure gauge light is on it means that your car dose not have the oil pressure needed to properly oil the moving components, if you are sure that this is not the problem then replace the sensor and the light should shut off.
One of the reasons that your check gauge light comes on is if your OIL PRESSURE is TOO LOW ( you can have plenty of oil but if your oil pump has failed you won't have enough oil pressure , your gauge actually shows oil pressure , it's not an indication of oil level ) If your engine is clattering , DO NOT RUN THE ENGINE , have your vehicle taken by tow truck or flatbed truck to a shop / garage where a professional can evaluate the situation
It's a device that registers or shows you on a dial with a pointer inside of it, how much oil pressure is inside of the engine when it's running.
step one,is your oil pressure at 80 psi ? or is the gauge tellin you it is? step two,diagnose the problem.
Connect the wiring harness to the back of your oil pressure gauge. Secure the oil pressure gauge with the retaining screws.
Defective gauge, defective oil pressure sending unit, low of oil, defective oil pump.
First, you need to install a mechanical gauge to insure that your oil pressure is low. You could have a bad oil pressure switch. If it shows that the pressure is low you will have internal problems. One of the biggest mistakes made is to assume that the oil pump is the problem. The oil pump is exactly what it says. It only pumps oil and the rod, main and cam bearing provide the pressure as the oil is forced By the bearings.
You need to install an external oil pressure gauge and determine the true oil pressure. The problem could be just an oil sending unit.