Well it looks like the issue is probably fixed, and what a silly reason it was. Had the battery be completely dead when I went to go to work Friday, I thought the alternator might have gone because the battery had 19 written on top (the year I assumed it was changed) and tested fine on the multimeter.

Jumped the car and after running it for a while tuned it off and tried cranking it, was super sluggish at first and after about 10-15 tried it managed to start. At that point I tested it again with the multimeter and sure enough it was WAY low. I go to put the new battery in and what do I find? SOMEONE PUT 19/6/14 ON THE BATTERY BUT THE ONLY PART SHOWING WAS THE 19. It's was an 8 year old battery, apparently me and and multiple mechanics missed it and after changing it, the check engine lights gone and looks like everything is working correctly. I just need to clear the error code from when the sensor was tested, I'm betting the ECU is gonna have no issue being connected to, looks like it might be all good now.

If anyone in Brisbane has a cable and would be kind enough to clear things for me let me know, I'll grab a 6 pack as thanks, I also now have a flashed ECU coming in the mail that I don't need if anyone is looking for one cheap 😂