TurboTax can not access, and does not have access to your tax return for any tax year. Only you and the IRS do. If you used the online version to file the tax return for whatever tax year you need, then you have to log into the same exact account you used to complete and file that tax return with. Then you and only you can access it.
If you used the CD version of TurboTax, then your tax return file only exists on the computer you used to create that tax return with.
You can order a transcript online for whatever tax year you need at https://www.irs.gov/individuals/get-transcript