Got kind of a similar question, same car same year; 04 grand prix...my 6cd radio is acting up, will swapping it out with another one that came from the exact same make and model work seamlessly? ie no codes, lock issues?
Thanks and sorry if i'm in the wrong section for this...new to the site.
Ok so I installed an OEM radio and apparently its plug and play, no issues or dealerships to deal with. Thanks all