The amount reported with code D in box 12 of your W-2 is amount of elective deferrals you made to your 401(k) (or federal TSP). If you completed the Retirement Savings Contributions Credit portion of TurboTax's interview, you would have provided the additional information necessary to determine if you qualified for the credit and TurboTax would have automatically considered the code D amount when determining if you qualify for the Retirement Savings Contributions Credit. If you qualified for the credit, TurboTax would then have automatically included Form 8880 in your tax return. If you failed to complete this portion of the TurboTax interview, TurboTax might not have included From 8880 even though you might have qualified. A tax credit can only decrease, not increase, your tax liability.
To amend a tax return, follow the instructions in this TurboTax FAQ:
<a rel="nofollow" target="_blank" href="
https://ttlc.intuit.com/questions/1894381-how-to-amend-change-or-correct-a-return-you-already-filed"...>
