As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HYDRAULIC FLUID - L HYD TEMP HIGH CAS CAME ON AT CRUISE ALT OF 39000. FOLLOWED QRH FOR TEMP BELOW 135. AFTER COMPLETING THAT STEP, TEMP CONTINUED TO RISE AND GOT TO 265 DEGREES. WE COMPLETED THE CHECKLIST AND SHUT DOWN THE LEFT ENGINE. COMPLETED TROUBLESHOOTING AND FOUND LEFT HAND HYDRAULIC TEMP SENSOR HAD FAILED, PERFORMED HYDRAULIC SYSTEM ACIDITY TEST WITH NO DEFECTS NOTED.