Battery issues codes were from a low voltage?

The battery died due to a drastic change in temperature that we had and I plugged in my OBD2 sensor and it said all these codes were from a low voltage because the battery wasn't putting out enough power. I replaced the battery, put everything back to the way it was and it's still having issues. However, I did not replace the auxiliary battery. Should I go ahead and replace the auxiliary battery too to help with it? Or did just replacing the main battery work?