To access the 2015 tax return that was completed using the online editions and you did not complete a 2016 tax return with the online editions -
If you did not pay for the one of the 2016 online editions of either Plus, Deluxe, Premier or Self-Employed you will need to start a 2017 tax return using the online Free editon and create the account with the exact same user ID you used to create the prior year online account - https://turbotax.intuit.com/personal-taxes/online/
After starting the tax return with the Free edition you will need to upgrade to the Plus edition and pay for the Plus edition ($29.99) so you can access all the prior year online tax returns through October 2019.
To pay the TurboTax online account fees by credit card, without completing the 2017 return at this time, click on Tax Toolson the left side of the online program screen. Then click on Print Center. Then click on Print, save or preview this year's return. On the next page, to pay by credit card, click Pay Now. On the next screen just click on the Continue button. The next screen will show a review of your Fees, click on Continue. Complete the next screen to pay by credit card and click Continue.
