Turbo tax auto-inputs the first four letters of the entity. The IRS uses the first four letters of the last name (or first two or three if shorter last name).
I found this site helpful because it explains how the Special Name Control is established:
I had to call The IRS Business Specialty line for this answer and I didn't believe it but it worked. TTax would not allow me to file form 1041. The IRS guy said to put in the first 4 letters of the Trust or Estate. This is the official name you put in when you applied for the EIN# for your Estate or Trust. It WORKED!! and TurboTax finished filing my return electronically. Leave it to IRS to through in a secret code that you would never guess.