Hello All, PLEASE HELP!

The RAC man came out to the car last night and said in his opinion it was the oil pressure sensor that had gone.
Cool, It thought, so this morning replaced the sensor with a new one, feeling good, started the car and after a minute of fast idle on came the warning again!
Looked again at the switch and noticed the cable out of the plug had some exposed wire, so the question is, can I cut the plug off and replace it with a single spade connection? Obviously insulating it accordingly for weather etc. Or, does this morning need a reset via a computer?

I also have oil flush fresh filter and oil to do an oil change on the car tomorrow, hoping that it may clear out any sludge build up and help??!

So any help please let me know!!!

Thanks