As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 2408 - EWR - FLIGHT CREW REPORTED PACK NR 2 VALVE CLOSED. CREW PERFORMED AIR RETURN AND LANDED ACFT UNEVENTFULLY. SYSTEM WAS MEL. IAH MX REMOVED AND REPLACED SLEEVE AND PERFORMED OPERATIONAL CHECK SUCCESSFULLY. ACFT WAS APPROVED TO RETURN TO SERVICE.