Roberthh wrote:The CAN bus uses a diffferential signal. Given that, connecting the GND of PyBoard to the GND of the car is not mandatory, but it might help in case of noise & spikes. If you power PyBoard from the car's power network, then a common GND can be assumed anyhow. Us proper twisted & shielded cables, unless tehse are very short.
but wouldn't it there be a problem in that PyBoard has 3.3V and OBD2(car) has 12V ?