As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON CLIMB OUT OF ACFT WOULD NOT PRESSURIZE. RAN EMERGENCY CHECKLIST PRESSURIZATION WOULD NOT WORK IN MANUAL MODE EITHER. GOT A CABIN PRESSURE WARNING. RETURNED TO FIELD. LANDING UNEVENTFUL. CPC POSTED FAULT CODES "CPC/OF VALVE DATA FAILED" AND " INDICATION MODULE FAIL". REMOVED AND REPLACED AFT OUTFLOW VAVLE IAW AMM 21-31-16-000-801 AND 21-31-16-400-801 ALSO REPLACED CABIN INDICATION MODULE IAW AMM 21-31-11-000-801 AND 21-31-400-801. OP'S CHECKS GOOD. RETURNED TO SERVICE.