Allegedly you used to be able to but, as my current situation shows, that's not the case anymore.
I posted about it if you'd like to go read it but the basic gist is, once it goes into limp mode (at least, for my issue of "DPF 100% full and code p0428), it absolutely WILL NOT ALLOW that code to be cleared regardless of new sensor install or not and, if you cannot clear codes, you cannot regen. The program won't allow it.