Remove oil sending unit and replace with a mechanical gauge
On installed transformer a test is performed to check weather it has any oil leakage or not, the test is called pressure test, more precisely pressure leakage test.
It's oil level or pressure. If level ok, pressure test.
it is the oil pressure sensor. Check your oil level, then test your oil pressure sensor.
You will need to run an oil pressure test with a pressure gauge.
To test an oil pump, first ensure that the vehicle is off and cool. Remove the oil pressure sending unit or oil pressure gauge and use an oil pressure gauge to measure the oil pressure while cranking the engine. If the pressure reading is within the manufacturer's specified range, the pump is likely functioning properly. Additionally, you can check for proper oil flow by observing the oil return to the oil pan or using a flow meter if available.
Oil pressure test.
To get oil pressure - you have to either tap in the existing pressure sending unit's oil port or get a sandwich adapter plate - that fits between the oil filter and the block. In any case - you will need an oil pressure sending unit and appropriate gauge to go with it.
Test with a mechanical gauge to accurately detemine oil pressure Could just be a defective oil pressure sensor
Low oil pressure. Now the question is does it really have low oil pressure or is this a false reading. Check the oil level and add as necessary. If it was low that is your problem. If not, You need to check the oil pressure sending unit for loose wires or a leak. If you find it is OK, then you will need to see if you indeed do have low oil pressure. You can have someone run an oil pressure test or you can simply replace the oil pressure sending unit as it may be defective. I would also replace the oil filter and make sure you are using a good quality correct filter. If replacing the sending unit, checking the oil level, and replacing the filter does not correct the problem, you will need to have an oil pressure test run. If you find you have low or no pressure, the oil pump has probably failed.Low oil pressure. Now the question is does it really have low oil pressure or is this a false reading. Check the oil level and add as necessary. If it was low that is your problem. If not, You need to check the oil pressure sending unit for loose wires or a leak. If you find it is OK, then you will need to see if you indeed do have low oil pressure. You can have someone run an oil pressure test or you can simply replace the oil pressure sending unit as it may be defective. I would also replace the oil filter and make sure you are using a good quality correct filter. If replacing the sending unit, checking the oil level, and replacing the filter does not correct the problem, you will need to have an oil pressure test run. If you find you have low or no pressure, the oil pump has probably failed.
Low oil pressure because of a failing oil pump. It can also be nothing more than a defective oil pressure sending unit. Replace that before moving forward with an oil pressure test.
Possible clogged oil galley, filter, defective oil pressure gage, or the use of an oil that is the incorrect weight. Replace the oil filter with a Purolator filter and change the oil. Install 5W-30 oil. If the pressure is still high then you need to have the oil pressure tested with an accurate test gage, to see exactly what it is.
Remove oil sending unit and install a mechanical gauge to actually test oil pressure Low pressure may be caused be worn internal engine parts (bearings) or a weak oil pump