Look inside the OBD cable and note which MCU is placed (E.g. FT232R or FT232RQ), get its datasheet, find the RXD and TXD pins, solder the first visible contact point to your Arduino digital pins of ...

An arduino code that reads Honda OBD Protocol and translates it to ELM327 protocol. I use Torque app to read and display the data on my android phone (via bluetooth), and a LCD (2x6) to display it on ...