As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
STL - INFLIGHT ORD-DFW. CREW REPORTED CABIN PRESSURIZATION PROBLEMS AND FLOW LIGHT ILLUMINATED, 500 TO 600 FPM CLIMB IN CABIN. FOLLOWED QRH PROCEDURE AND CABIN CONTINUED TO CLIMB. EMERGENCY DECLARED FLIGHT DIVERTED STL LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REPLACED RIGHT AIR CYCLE MACHINE. SYSTEM GROUND CHECK NORMAL OPERATION.