As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CLIMBING THROUGH 11,500'. RECEIVED CABIN PRESSURE MASTER WARNING, CABIN PRESSURE CHECK LIST WAS ACCOMPLISHED AND WERE NOT ABLE TO CONTROL CABIN IN MANUAL MODE. RETURNED TO FIELD. LANDING UNEVENTFUL. INSPECTED AND CLEANED MAIN CABIN DOOR AND AFT CARGO DOOR SEALS, NO DEFECTS NOTED. PRESSURIZED ACFT IAW AMM TASK 21-00-00-863-801, NO DEFECTS NOTED. DEPRESSURIZED ACFT IAW AMM TASK 21-00-00-863-802, ACFT OK FOR CONTINUED SERVICE.