As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT FL 290, RECEIVED A HYD NR 2 HIGH TEMP CAUTION MESSAGE. COMPLIED WITH QRH AN LANDED AT NEAREST SUITABLE AIRPORT. EMERGENCY DECLARED. COULD NOT DUPLICATE COMPLAINT, PERFORMED FUNCTIONAL TEST OF HYD SYS 2 TEMP INDICATION IAW AMM 29-10-00-720-802. NO FURTHER DEFECTS NOTED, ALSO RAN ENGINE AT POWER SETTING IAW AMM 71-00-00, COULD NOT DUPLICATE.