On my Cadillac I get engine light to come up because I have changed my petrol cap and sensor is malfunctioning. I got myself wifi ELM 327 OBD-2 reader, and by using my laptop I managed to get RPM of engine - it must work. However full version of application costs ~150$ and functionality for error code resetting is not provided in free version. I then tried looking for Android app that would allow me to reset error codes, but after 2 hours of installing tens of apps (including upgrading to paid versions up to 10$) I finally gave up.
Does anyone know Android app that would work for Cadillac CTS? Would prefer free (but would be perfectly happy with paid if not ridiculously expensive).