You can manually add the 4th line.
Here's how to do this in TurboTax Online:
- Navigate to Federal Taxes, Wages & Income, Job (W-2), Add/Edit
- On the next page select the W-2 has the local tax showing up on state, using the pencil icon
- Continue through information about company
- Then, choose Add another box 12 item, and add the amount with Code W