As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING CLIMB, THE NR 2 HYD ISO VALVE CAUTION BEGAN TO ILLUMINATE AND CHIME. THIS CONTINUED INTERMITTENTLY AS WE CONTINUED AIR TURNBACK. DEFECT CONFIRMED AS AN INDICATION ISSUE. THE ISOLATION VALVE OUTLET PRESSURE SWITCH WAS REPLACED.