As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LAX - CREW REPORTED AIRCRAFT WOULD NOT PRESSURIZE AFTER TAKEOFF. EMERGENCY DECLARED FLIGHT RETURNED LAX LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REPLACED EQUIPMENT COOLING OVERBOARD EXHAUST VALVE. SYSTEM GROUND CHECK NORMAL OPERATION.