realistic pro 2005 trouble shooting

[xlubbock]

I have a pro 2005 and the display is flashing a trouble code when the unit is running and it beeps. need info on what it could be so i can fixit.

 

[WPXN]

Try replaceing the 9volt battery..

 

[ocscan]

I have a 2006, what is the trouble code flashing????