Carl
Level 15

Get your taxes done using TurboTax

If it's the 5-digit e-filing PIN, that number doesn't change from year to year unless you take physical action to change it. If you e-filed last year it was imported from last year's .tax2016 file.
If it's the 6-digit IP PIN, then in the search box at the top left enter IP PIN and take the "jump to" link when it appears.