As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON CLIMBOUT, THE LEFT HYDRAULIC PRESSURE LOW LIGHT ILLUMINATED. THE LEFT HYDRAULIC PRESSURE DROPPED TO ZERO WITH THE PUMP IN EITHER LOW OR HIGH. QUANTITY AND TEMPERATURE WERE BOTH NORMAL. CREW RESTORED PRESSURE TO NORMAL IN THE LEFT SYSTEM BY USING THE ALTERNATE HYDRAULIC PUMP. THE FLIGHT RETURNED TO A SAFE LANDING BACK TO MSP WERE MAINTENANCE REPLACED THE LEFT ENGINE DRIVEN HYDRAULIC PUMP. THE AIRCRAFT RETURNED TO SERVICE.