As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ACM OVERHEAT ANNUNCIATOR ILLUMINATED AFTER TAKEOFF. ABNORMAL CHECKLIST WAS FOLLOWED AND RETURNED TO AIRPORT. AFTER ILLUMINATION OF THE ACM OVERHEAT ANNUNCIATOR, A WARM RUSH OF AIR AND A BURNED ODOR DETECTED WITHIN CABIN. TROUBLESHOT SYS DOWN TO A RESISTIVE TEMPERATURE SENSOR. R & R TEMP SENSOR IAW THE MM 21-51-00. OPS CHECKED OK.