No - While it's important to enter all the information on your W-2, you don't need to file an amended return. The items listed in Box 12 of your W-2 are informational and are covered elsewhere on the form. For information about all the codes in Box 12 of the W-2, please see this TurboTax Help article: What do the letter codes in Box 12 of my W-2 mean?
In your case:
- Code C is the taxable cost of group-term insurance over $50,000. If you had group term life insurance through your workplace, the premiums for any value over $50,000 become taxable income to you and are included in box 12. The taxable amount is already included in your Box 1 wages. You don't enter the amount anywhere else in your return.
- Code D reports your contribution to a 401(k) plan. This amount is already subtracted from your Box 1 wages.
- Code DD is the total cost of what you and your employer paid for your employer-sponsored health coverage plan. This amount is for information purposes only — it doesn't affect the numbers in your tax return.
