Convert vehicle from business use to personal

I work as a real estate agent.  I have a 2002 SUV, purchased new, that I put into business use (mixed business and personal) in 2011.  In 2019 I stopped using it for business use and went back to just using it for personal.  Turbo Tax  informed me I may have potential 179 carryover.  What is that and where do I input that information?