When I plugged it in to my MacBook, it showed up as a serial interface. And it used AT commands. I found some Python code to speak this protocol, and I thought I could now talk to the car.
When the code worked (which was about 50% of the time!), the information it gave me was very limited, mostly just about the engine. Surely there had to be more…
So I dove deeper, and looked into what’s actually on the OBDII port. Sure enough, there is a CAN bus! Many of the USB to CAN transceivers were thousands of dollars, but I found a moderately priced one that gave me full access. We were in business, and I could read all the CAN messages on the bus.