Hi.

I am wondering what the difference is between these 3 busses,
I own a Citroen C3, and i would like to measure the Speedo and RPM gauge "real-Time" would OBDII be significant to do that, while also taking care of everything else..?

i would also like to know for ex.

which doors a open?
is the head light low and high beam on/off

what is the cunsumbtion

and so on..

which of the busses would i need to do those things..?

and can anyone give me an idea what the different busses does?

Thanks