This is a weird question, and I don't really even have the prerequisite knowledge to ask it properly, but basically, I would like to mess with my car's (E30) OBC (On Board Computer). I found a PDF (https://www.millerperformancecars.com/files/bmw%20electrical%20manual/1989%20BMW%20325i%20-%20325is%20Electrical%20Troubleshooting%20Manual.pdf - Page 110) that explains what wires go to what, but I have no idea how I'd interpret the data I'm getting. Is there a way to like, test these wires to find out what comes through them, and is there a way of interpreting that information? What kind of tool would I need? I'm assuming once I figure it out I can do something using an Arduino or Raspberry Pi 0.