We have a 430 in my families Piper Arrow. To get that inbound course message to stop popping up set the obs to the heading that it says in the message. Even though this will not change the needle at all, unless the GPS is in GPS OBS mode, the message will go away. It also will give you a good reference in your instrument scan as to the heading you should be tracking. This is the same thing I would do if I was flying an ILS or LOC approach.