I received a corrected W2 where the only changes were in Box 12 for codes DD and W ($440 and $12, respectively). My original W2 did not have these codes reported; how can I determine if I need to file an amended return? Thanks!
Box 12 Code DD is for informational purposes only - it represents the employer cost of health insurance but it doesn't affect the tax return.
Box 12 Code W represents HSA contributions. While the change in your tax return is likely to be very small (if any) due to the amount, having this code would trigger Form 8889 to be completed. So, you may want to amend the return just avoid any sort of auto-generated notice from the IRS.
This question is what I’m trying to figure out now. Line 12 had DD and W on corrected w2 , My return was accepted today then i received my corrected w2. Does this mean i need to amend my return now or wait.
Wait to amend your return. The form to amend your return, Form 1040X, isn't ready yet, and it is always best to allow time to receive your original refund first before amending the return.
It is likely to make a tiny difference in your return, but as @AnthonyC points out, it is best to make the update just so that everything matches up with the records that the IRS has. While we easily see that $12 is a small number, a computer sees only a mismatch and kicks out a letter that lands in your mailbox and ruins your day. (No one likes mail from the IRS unless the envelope contains a check!)
Here is some more detailed information about how to amend your return in TurboTax when the time comes: How to amend a return in TurboTax.