As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RETURN TO FIELD, UNABLE TO CONTROL CABIN PRESSURIZATION IN FLIGHT. NO MASKS DROPPED. RECEIVED A NR 1 PACK OVLD CAUTION AFTER LANDING. REMOVED AND REPLACED THE PRESSURIZATION DIGITAL CONTROLLER IAW AMM 21-31-01, FUNCTIONAL TESTED GOOD IAW AMM 21-31-00.