Originally Posted by Cell

I figured it out.

With the standard cable you need a tuner to make the change.

If you have the full tuner cable then you can just open with ROM Editor and edit your tune. You then navigate around till you see Catalytic Efficiency, not the exact term used in the editor but close, and click it to turn it on. There will be two to turn on. Now my OBDII scanner reads it and I just have to drive till it is ready.

My car is boosted with no cats. I can still pass emissions here in Chicago but I just need all the monitors they look for to be ready to take it in. The trick is to get it in right after resetting the ECU and driving it till all monitors are ready before any codes pop.