Gremlin SES Light 01Path

[cps2001path]

This is somewhat of a follow-up to a previous post I made but I am getting a new OBD code so I figured I would make a new post. I recently replaced the Cam Position Sensor and Crank Position Sensor on the driver side and both downstream O2 sensors, all of which I was originally getting OBD codes for. I cleared the codes, unhooked the battery for a couple hours, reconnected the battery, drove the truck for 15 miles and the SES light comes back on. Now I am getting code P0420 (Two-way Catalyst System Bank 2).

Is this a result of the ECM relearning the proper mixtures after replacing the downstream O2 Sensors and will clear itself up after a while? Or is it another real problem?TIA