Enter these only in box 12 of TurboTax' s W-2 form. The code D entry is the amount that you electively deferred to the 401(k) and, when entered on TurboTax's W-2 form, TurboTax automatically considers this amount for the Retirement Savings Contributions Credit. Your employer has already excluded the code D and code W amounts from the amount reported in box 1 of your W-2, so you to not get to exclude or deduct these amounts again on your tax return.
