If I use an aftermarket oil pressure sender will it throw a code?

 

Possibly. That's a pretty open-ended question. There are a lot of aftermarket sensors out there.

 

Perhaps the code is coming on for a reason and the sensor is functioning as it should. Hooking up an oil pressure gauge to spot where the sensor goes will tell you if your pressure is good and there is an electrical fault. If that is the case then get the wiring diagram and grab a DMM and figure that shit out instead of throwing parts at it.