I'm still implementing different bits. But it can get all of the following:
RPM
Idle Speed Error
Road Speed
Battery
Accelerator Position (all 3 track voltages and supply voltages)
Coolant Temperature
Air Inlet Temperature
Mass Air Flow
Ambient Air Pressure
Manifold Pressure
Cylinder balances
I can also get:
Fuel Temperature
EGR Modulator
EGR Inlet
Wastegate Modulator
I can also read (and clear) the fault codes and decipher them to give the correct codes. But I wasn't going to bother with this until I realized people may be interested in a cheap and cheerful solution. I'm only really doing this to enable me to build a gauge pod with all of this information (hence why some values haven't been put in).