You can do a simple antenna disable, or you can replace the module with a third party hacked module.

Here's how easy it is to disable the antenna- https://www.youtube.com/watch?v=KAbTy_jFcbc

There are also hackers who have reverse engineered the Onstar hardware and created replacement hardware that allows you to get bluetooth working in cars that didn't support it, and adds other features as well. It can also fool the onboard computer to prevent any errors.