How to record a car donation that was partially used for business?

I bought a 2012 Toyota Prius in 2012 for personal use.  I started to use it for business on 1/1/2016 and then donated it to a non profit organization on 12/27/2016.  The market value of the car at the time of donation is about 12K according to KBB.  I bought it for 24K.  Turbo Tax shows a loss of 12K on form 4797.  Is that correct?  Can I also deduct it in the "Donations to charity in 2016" section of the deductions & credit?  Thank you for your help. Thank you.