Get your taxes done using TurboTax

There should be an option in the Your Total Business Income section to choose Dispose of Business Property. When you work through that section TurboTax will automatically pick up prior year section 179 if any and properly account for it when you enter your sales information. The sale will be reported on a supplemental schedule attached to the shareholder's K-1 form that is called Shareholders disposition report for all assets with sect 179 expense taken, it will look like this:

You will see an entry on line 17 of the shareholders' K-1 referencing the statement.

It may be that you didn't report the section 179 depreciation in TurboTax when you set up the asset, in which case it might not be dealt with properly when you sold it. If so, you can delete the asset an re-enter it and then report the sale.