If you transferred your file from last year's TurboTax, the program will already have that number. Otherwise, the program will ask you if your rental had passive loss carryovers.
The passive loss carryover were reported on Form 8582 in prior years. When you go through the introductory part of the rental section (where it asks for the address etc. of the rental) and you indicate it was sold, that will release the passive losses.
It actual loss will show up on Schedule E.
