As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CABIN PRESS WARNING CLIMBING THROUGH. BLEED AIR FLOW NORMAL RETURNED TO FIELD. LANDING UNEVENTFUL. REMOVED FROM SERVICE. CDS SHOWED NO FAULTS FOR CPC, L NAPRSOV AND PACK FCV FAULTED IN CDS/ECS. ATTEMPTED TO PRESSURIZE A\C, BUT WE COULDN'T GET AIRFLOW FROM ENGINES OR APU. R & R PACK FCV, IAW AMM 21-52-01-000/400-801. OPERATIONS TEST GOOD. RETURNED TO SERVICE.