As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DFW - CREW REPORTED LEFT HYDRAULIC SYSTEM PRESSURE ZERO. EMERGENCY DECLARED FLIGHT RETURNED DFW LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REPLACED LEFT ENGINE HYDRAULIC PUMP THAT WAS BAD AND FILTERS. SYSTEM GROUND CHECK NORMAL OPERATION.