I found a vacuum line that had popped loose. I think that was the P0401 codes remedy. I cleared the codes and took the car for a short drive. No CES but I rechecked the codes anyway.
I: The P1000 code is still in there. Could this be due to having the rear O2 sensors turned off with the tuner?
Me: Yeah, I think that is it. Turn the rear O2s on an install MILs and they will likely go away with some mileage. Thanks me, for all the help.
I: Oh, no problem. You probably should have Google searched it a bit more before posting.
Me: Yeah, you're probably right. Don't get so panicky next time.
This, your computer needs to have a clean slate to eliminate the pending code, or you just fix the issue, reset the code/batteries and drive it normally. Usually it takes either a really long drive or several drives with the engine seeing different RPM's and road speeds.