There is a process in scanner to calibrate the cam sensors with crank sensor. Or some sort of learning situation involved. Your scanner may not have this function. Our Snap on does and fixed mine. The inline 6 is finicky about quality sensor.
So did you have the P0017 initially and that's why you replaced the camshaft sensor? If so, it's possible that the real culprit was always the CPAS, so changing the Cam sensor never really fixed the problem and it just popped back up. I'm with Mooseman in thinking that your P0449 is a separate issue. Check that CPAS as he suggested. You may also find that even if there's no oil in the connector that the body of the CPAS will rotate in the housing, or that the screens are gummed up or even missing. In any case, if you've got any questions about the maintenance of your truck, especially in terms of mileage and oil changes, you might be better off just changing the CPAS (and as he said, AC Delco or Delphi...these trucks are finicky).