As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DAY - INFLIGHT DCA-ORD. CREW REPORTED PRESSURIZATION PROBLEMS. CABIN OXYGEN MASKS WERE MANUALLY DEPLOYED. EMERGENCY DECLARED DIVERTED DAY LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REPLACED BOTH RECIRCULATION FANS. RECIRCULATION FAN FILTERS WERE QUARANTINED FOR FURTHER TESTING. SYSTEM GROUND CHECK NORMAL OPERATION.