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If you previously had XM, there would be three purple wires to jump over; not two. Reason for the splicing of the wires is that the serial data link comes into the radio and then is supplied to Onstar and XM via the radio link. The Pioneer head unit does not pass this link through. There should be two purple in the 24-pin and 1 purple in the 12-pin. If you don't have factory XM, no problem.
Leave the factory XM if installed connected to power.

Did the adapter come with a relay setup that had to be wired for ignition on signal? I would have to confirm by looking at some schematics, but it sounds like the there is an incorrect wire connected and I don't have a schematic for the adapter you are using.

It is also very early...