As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DECLARED EMERGENCY. DURING CRUISE A HYD SYSTEM ENGINE DRIVEN PUMP LOW PRESSURE LIGHT ILLUMINATED, QUANTITY WAS AT 1/4, QUANTITY (A SYSTEM) CONTINUED TO DECREASE TO ZERO. FOUND O-RING LEAKED ON "A" SYSTEM HYD MODULE. REMOVED AND REPLACED O-RING PER AND NR 1 ENG DRIVEN HYD PUMP MM.