As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT MAIN HYDRAULIC PUMP LOW PRESSURE LIGHT ILLUMINATES IN FLIGHT. REFERRED TO QRH. RETURNED TO LAX FOR LANDING. REPLACED LEFT ENGINE HYDRAULIC PUMP WITH SERVICEABLE UNIT, CHECKED GOOD. NO LEAKS. SN OFF MA575897 SNON: MX521768. ALSO REMOVED INSPECTED AND REPLACED GREEN SYSTEM HYDRAULIC PUMP FILTER, ALL FOUND GOOD. NO LEAKS AFTER REPLACEMENT.