Hello, I'm a electrical engineer.
I'm working for my self in a project like this. I'm using a elm327 interface (
bought on ebay) and i'm developing a java program to send and receive commands from the elm327 device.
What we need to do? Develop the device that will be connected to the car and acess them via bluetooth?
If you want more information from me, please contact me. I can put some samples of the project in my portfolio at freelancer.
Best regards,
Tiago Felício