As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UNABLE TO PRESSURIZE ACFT IN ALL AUTOMATIC AND MANUAL MODES OF FLIGHT. DIVERTED, LANDING UNEVENTFUL. FOUND LOWER AFT SEAL TORN, RETIGHTENED SCREW FOR AFT SILL PLATE. R & R AFT CARGO DOOR SEAL REF Q400 TASK 52-31-26-000-801 & 53-31-26-400-801. PRESSURIZED REF TASK 21-31-00-720-801. OPS AND LEAK CHECKS GOOD. RETURNED TO SERVICE.