2006 Silverado 2500hd 6.0 gas read failed

[Drummond95]

So I am trying to install the tune into my 2006 Silverado 2500hd gas but every time it tries to back up the stock tune it keeps giving me read failed. I have disconnected every thing that is aftermarket radio, amp, HID etc. but it still is giving me the message I made sure the device is completely updated and it is now but still getting the same message. I have read all of the other threads but I can not figure anything out.

[mikel]

is there an aftermarket stereo harness tied into the stock harness?