Do I need to file an amendment because of a corrected W2 where Box 12 codes C and W were changed and it did not impact the amount I owe nor the amount I need to pay?

[ghost]

No. Since the IRS also gets this correction, they should figure out it's impact without amending.

[CarolynM]

No, you do not need to refile unless it impacts your tax return

Do make sure you keep a copy for your records with the return you filed and a note of the difference.