Check Charging System

For the past month my 2013 Hyundai Sonata Hybrid has been having issues keeping the 12 volt battery charged. When the Internal combustion engine runs there is no alternator output. When running on the Hybrid battery there is more than 14 volts to the battery, but not always . I get these readings with a diagnostic tool plugged directly into the OBD port. Living in Minnesota the internal combustion engine runs quite frequently to maintain heat. When the battery reaches 12 volts or less I'll get a Hybrid warning and a check charging system warning. The check engine light will display along with the battery and wrench symbol light up. A new battery was installed a little over a month ago. No codes are stored in the ECM or TCM.. Any similar issues or suggestion on a repair?

Update
The battery, alternator and starter are all good. I recently checked them at O'Reilly Auto Parts, Their scanner and mine won't pull up the codes.