Did u ever get ur ELM327 to work on ur impreza? After some research i'm starting to wonder if only american imprezas had obd2 since 96 and that we have a European one not required to have obd2 until 2001.
Wiki says:"1996: The OBD-II specification is made mandatory for all cars manufactured in the United States to be sold in the United States.
2001: The European Union makes EOBD mandatory for all gasoline (petrol) vehicles sold in the European Union, starting in MY2001 (see European emission standards Directive 98/69/EC)."
Everyone is telling me to buy one of those adapter cables as they are cheap.
Managed to find the wiring of these cables in some far corner on the internet and opened up my elm327 turned out most of the wires ended on underpopulated pins.
Than I hooked up all the different combinations for the 6 data lines the elm327 had to the (possibly) 2 data lines on the yellow plug (shown in this post).
Sadly no connection and no luck.
Monday, December 1st, 2014 AT 10:11 AM