If you were under age 59½ at the time of the distribution, code J is correct. In that case the taxable amount must be determined on Form 8606 Part III. Enter the Form 1099-R as received. Be sure to click the Continue button on the page that lists the Forms 1099-R that you entered and, when asked, be sure to enter the amount of your Roth IRA contribution basis so that TurboTax has then information necessary to complete Form 8606 properly. The entire gross amount will be included on Form 1040 line 4a but only the taxable amount, if any, will be included on line 4b.
