Ended up getting a usb one. https://www.ebay.com.au/itm/ELM327-O...72.m2749.l2649
just hope car holds together till i get it in mail,and hope it shows something that may be causeing rattle, I know its not going to show internal problems but hopefully something.
doesnt say it works on opel/gm but im guessing it should.hmmm