First, press and hold presets two and three for a few seconds. Three digits will come up on the display. These are the first three digits of the factory unlock code.
Press the AM/FM button on the unit and another three-digit number will read out. These are the last three digits of your code.
Call 1-800-537-5140. You'll be asked for a dealer code, and the one I have from the forum is 202107; I have also heard that 139010, 206053 and 620529 may work. You may need another if they ever disable this number. Enter this number and then press the pound (#) button.
Now enter the six-digit code that you got from your stereo, first three digits first, then the last three. You will be given a four-digit response code. Make note.
In your car, hit the HR button and put in the first two digits of the response code. Then press the MIN button and put in the last two digits of your response code. Press AM/FM and then SEC should read out on your radio.
You should be unlocked!
Hope this saves some folks whose batteries die or get a new head unit on eBay that comes Theftlocked a little help.