2006 STS will not shift in to park - 2006 Cadillac STS

Try to reprogram the theft system this should take 30 minutes, Do this with the ignition on hit the start button but don't let the engine start the light will stay on for about 10 minutes then turn off when it turns off turn the switch off then repeat this sequence 2 more times ignition on touch starter wait 10 mins. when the light goes off ect. I hope this helps. Take care.

open the hood and look on top of the transmission,Remove he gear cable from switch .now u can shift from trans

The fuse is located under the rear seat in the fuse box.Trunk/valet fuse.

It probably thinks you're trying to program a key & fob. I really don't think you can just 'make' a key - I think it needs to be a regulation key fob + key for that particular car - security features and such.

I suggest you have the car's computer scanned for trouble codes. If there are codes , they will identify where the problem is. Auto Zone and Advance Auto will do a scan.

I hate to be the bearer of bad news but sounds like your transmission has gone out. But shifting to park and no motion is an acceptable behavior:)
One other possibility is the linkage to the transmission has broken and you are not actually shifting gears when moving the shifter.

O2 sensor has detected a lean condition vacuum leak

Sounds like a broken shift cable or stretched out have someone hold shifter like their putting the car into park , not running .
while they r doing this open hood find shift linkage try pushing it into park if it does then you've found your problem , and by the way please block wheels so car doesn't roll to remain safe while doing this .

Its a shift position sensor that is sending bad signal.

It is not visible from the top. It is on the back side of the engine. Visible from the bottom of the vehicle. Use a jack stand whenever going under your vehicle to be safe. Always engage the parking brake, and have an assistance watching you. Good luck.