Turbo Tax 2018 does not allow me to access codes V, W and X in part 3 box 17 what Should I do?

Double check that you are in the entry section for a SCorp (1120S) form K-1, as box 17 on a 1065 K-1 does not have codes that go up to V, W or X.   Therefore, you may be entering the K-1 in the incorrect K-1 section.  Look at the top left of the K-1 form and it should state whether it is a 1065 K-1 or an 1120S K-1.  If you have received the wrong type of K-1 form, you will need to go back to the preparer of the form for correction. 

If you are entering the form in the incorrect K-1 section, delete the K-1 entry form that you have just entered from the K-1 summary screen.  Select that you are done entering K-1's of that type so that you will be brought back to the type of K-1 entry screen where you can pick the K-1 for an SCorp as Box 17 in an SCorp K-1 has code values of V, W, and X.

See a sample screenshot below, plus a picture of the SCorp Box 17 code values.