If it doesnt have pre and post o2's the defoulers wont work. They are only for knocking out bad cat codes. The pre's do the fuel ratio. If its just has 2 o2 sensors pre cat then it has no way of knowing about the cats. It probably has mini cats up at the motor and the first o2 sensor set are up there. Im just guessing but I can look it up for you if you want.

I still have alldata software which covers that car.