on this model the access 3 contains the software, so you dont need to update other modules
assuming your new access 3 is installed correctly, are you getting any fault codes
is this a new access 3 or known good or unknown condition
have you completed the features section or as mentioned copy from access 2 to 3, assuming same software version
did you copy your set up from the old access into access 2, then copy from access2 back into the new access3? you can do this in the utilities menu.
Did you dowload/update software? Normally after you swap an access module, you have to download software so all modules can talk to each other and have the latest software.