Due to tax law changes in force between 2018 & 2025 you can no longer "trade in" one vehicle for another ... in the TT program you must sell the old vehicle and enter the new vehicle as an asset.
If the sold vehicle is not still listed as an asset then either enter it again showing it is fully depreciated OR sell it off in the Sale of Business Asset section later in the program.
If you are doing this manually then here is the form instructions : https://www.irs.gov/forms-pubs/about-form-4797
