It might erase codes, but if there are any faults still there they will reappear. You should notice no other changes. During the summer months when my 190 is in storage the battery is out. When I place it back in service in the fall I install the battery. It starts right up and runs like it was only sitting overnight.

CA models of that era have some limited diagnostics and codes. Not sure about 49-state models. They may have some diagnostics/codes, but not as many as CA models.

Duke