1999 cadillac stereo check engine light

sorry, did not read the previous post...although i have installed decks in several newer GM's, i guess i havent come across that yet.  good to know.  btw, what does the plug look like?  have any links that may give me an idea?

I do not have a picture sorry, but the Caddies use a 32 pin harness and the standard "class 2" GM's use a 24 pin harness.

What info does the stock radio hold? Communicates with bcm??? new to me.

I see. Thanks for the knowlegde.

the 99+ VW's with the double din radio are also linked to all of the other electronics in the car.  i feel kinda bad for the people that ive done installs for because if they go to get a diagnostic test for any reason they are out of luck unless they brought the stock radio with them.  does anyone know if some kind of relocation harness or interface is made for that data system?

On the VW.. its because the remote wires are hooked up ... if the harness has only 1 blue wire from the vw harness only hook up the blue and not the blue/white.   when they are both blue and blue/white put together goin into the blue.. it will send a + at all times when radio is on.. so for some reason it interfers the computer.

In 1998 VW substituted the antenna turn on cavity for data for communications between the radio and BCM. Putting 12V down this wire locks up the BCM for diagnostic testing. 1998 and newer VW's and select other european vehicles now have the antenna booster turn on duplexed in the antenna coax.