W-2 Box 18 is higher than box 16

Probably nothing.  Enter your W-2 into, into. the program just as it is.

Box 18 (W-2) for Local wages may often differ from Box 16 for State wages.
 

Box 16 reports the total amount of taxable wages earned in that state. If you worked for the same employer in multiple state, there may be multiple lines of information.
 

Box 18 reports the total amount of wages subject to local, city, or other state income taxes. Often different than Box 16 and Box 1 (Federal Wages).

The differing amounts may be due to employer benefits.

If you are still in doubt, you can always contact your employer to confirm that your W-2 is correct.

Import/Enter your W2 here:

1. Open your return (if not already open).
2. Enter "W2" in the Search box.
3. Click on "jump to W2" link.  You may be redirected to Your W2 summary page where you can see if your two (2) W2 forms have already been added.
4. Select Work on my W-2 and Continue.   Or...
5. If you've already entered a W-2 or need to add another, select Add a new W-2.
6. Enter the 9-digit Employer ID Number (EIN) from your W-2, and select Continue.
7. If your employer is a TurboTax partner, the program can Enter Your W-2 for You and lead you through the steps to import your W-2.  Or...
8. If TurboTax doesn't recognize your EIN you can fill in your W-2 info manually yourself.