First time posting. I got a rc5500 with no start up. Display turns on and immediately shows wrench light. Battery meter displays but no code is displayed nor does it give me access to service. Push arrows any direction gives me nothing on display so I have no code to work with. Unit has info link which I bypassed. I've checked all fuaes and swapped relays at distribution board. I have also swap the display module getting same issues. I'm leaning towards a software issue but don't have a laptop with firmware so wanted to get any advice before I gotta place a service call. Thanks for any help.