Just bought this today. Updated it,,restarted it. Took it out to my 99 Durango to see the codes. Followed the directions and now all the letters on every screen are just black squares. What can I do to reset it or do I need to return it?
Well, pls check two things. There are two update for 439, program update and DTC lib update. Make sure both update are successful. Check the language in your setup of 439. Maybe you change the language to non-english.