As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAH TO CMH - DURING CLIMB, THE CREW RECEIVED A HYDRAULIC SYSTEM 2 FAIL MESSAGE THEN CONFIRMED THAT THE SYSTEM 2 QUANTITY WAS ZERO. THE AIRCRAFT RETURNED TO FIELD AT IAH AND LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED THE HYDRAULIC SYSTEM AND FOUND A HAIRLINE CRACK ON THE HYDRAULIC TUBE FROM THE BACK OF THE SERVICING PORT. AFTER CHANGING THE TUBE AND SERVICING THE HYDRAULICS, THE NR 2 SYSTEM OPERATED NORMALLY.