As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU OIL TEMP CAUTION LIGHT ILLUMINATED IN FLIGHT. AIRCRAFT THEN AIR RETURNED TO RDU BECAUSE THE NR 2 ENGINE IDG HAD EARILER BEEN PLACED ON THE DEFERRED MAINTENANCE ITEM LIST PER THE CL-65 MEL. AFTER ARRIVAL AT RDU THE APU OIL TEMP SENSOR WAS REMOVED AND REPLACED IAW WITH THE CL-65 AMM 49-91-25. OPS CHECKED APU OIL TEMP SYSTEM CHECKED GOOD AT THIS TIME.