You should have gotten a 1099-R this year to include the excess "contribution" distribution for your 2016 taxes. Enter the 1099-R exactly as printed on the paper form.
2016 TurboTax's drop down text assumes that you are entering a 2016 code P Form 1099-R. Code P is
the correct code as long as in the follow-up questions you indicate that
the Form 1099-R is a 2016 Form 1099-R.