Any John Deere techs? Clearing code question.

I've got a 9220 with autosteer. A few years back it threw an SSU 55 code. I'm pretty sure it deals with the autosteer. I tech friend of mine cleared the codes and it didn't come back until yesterday. I can't remember exactly how to clear the codes. I remember swapping a fuse and then using the turn signal but don't know the specifics. Any help would be appreciated....