The control number,
Box D on your W-2, is not required to
file your return, you can just leave it blank. If you are trying to
import your W2 and it is required for import, you can either contact your employer for the correct number or just manually enter
your W2 instead.
See below for more
information about how to enter a control number in TurboTax.
https://ttlc.intuit.com/replies/4417180