Is that thread sealer purchasable at dealer (Toyota genuine adhesive 1344) or is locktite 242 (blue) usable, in high pressure and oil environment?
Can anyone tell me, because you know I have no clue when it comes to things like this, can this part be changed WITHOUT having to do an oil change? Meaning, is it going to leak oil everywhere if I try to do it without draining the oil from the engine? I recently did a Crank Sensor and had no problems with oil leaking out while doing it.
Usually, a new oil pressure switch will have some blue or red locktight sealant on it. Some are a tapered thread, some use a copper/aluminum seal/gasket. You can always put some teflon tape on the threads which you can get from a department store or hardware store in the plumbing section. Make sure you thread it so when you screw it in, you are not going against the tape.
There would have to be some oil pressure sensor somewhere before any scanner could show it, and there's no such animal in a Gen 3, just a simple pressure switch to tell you "way too low" or "not way too low". When a diagnosis calls for knowing the oil pressure, that usually amounts to unscrewing the pressure switch and screwing in a plumbing fitting of the right kind, and a hose, and a pressure gauge, then starting the engine and looking at that.