If your error is in box 15 of the W2 then enter the same EIN as listed in box b.
It both EIN numbers are too long then you need to call your Employer to have the correct number updated.
Regarding Box 15-.
The only truly meaningful elements on a W-2 for income tax filing purposes are your employer's federal EIN (Employer's ID number), your own Social Security Number (SSN), and your actual wage data. If there was a mistake made with any of these items, then that would definitely be something that requires attention.
However, with respect to the Box 15 state number ID issue, it won't really matter what you input in Box 15 Employer ID, as long as the software will accept it (explained below). Make sure that the state where you work is correctly selected from the Box 15 drop-down menu, if it has not already been pre-populated by the TurboTax program.
Then, simply try leaving the Box 15 number space entirely blank at first. If there is any issue with Box 15 that prevents e-filing your return with a blank Box 15, and it absolutely requires some value in the software, then either try using your Federal EIN again here, or enter a "nonsense" value such as 12345 67890 (with a space in the middle, or not).
