As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PRESSURIZATION ISSUE AFTER DEPARTURE. RETURNED TO FIELD. LANDING UNEVENTFUL. INTERIGATED CDS, NO FAULTS IN CABIN PRESS CONTROL. FOUND PRESENT FAULT IN ECS 3004 PACK FCV. APU HAD NO FLOW WITH PACKS OR ENGINES. R & R PACK FLOW CONTROL AND SHUTOFF VALVE IAW AMM TASK 21-52-01-000-801/400-801. OPS CHECK NORMAL. PERFORMED FUNCTIONAL TEST OF PRESSURIZATION CONTROL IAW TASK 21-31-00-720-801. OPS TEST NORMAL. NO CDS FAULTS, NO CABIN PRESSURE WARNINGS. RETURNED TO SERVICE.