Hmm, I haven't heard that one, but I'm pretty sure that all new cars have to abide by the OBDII specifications. It's like a government regulation thing. Unless there is an even newer OBDIII out that I don't know about. In my car, the OBD port is under the dash to the left of the steering wheel. I don't know about mazda 3s', but i'mm 99% sure they have the same port(not necessarily in the same location though).