If your originally filed tax return included Form 8606 as required to report the nondeductible traditional IRA contribution, filing a corrected Form 8606 showing that no nondeductible contribution is necessary. However, unless there was some other reason that Form 8606 Part 1 needed to be included with your tax return, TurboTax won't prepare the corrected Form 8606 showing $0 on line 1. You'll need to prepare it manually.
Nothing about Roth IRA contributions goes on Form 8606. It's your responsibility to track your Roth IRA contribution and conversion basis. The IRS does not track these.
