As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: ENGINE 1 FIRE AND OVERHEAT WARNING DURING CLIMB OUT FROM CLT. INDICATION CEASED SHORTLY AFTERWARDS. DECLARED EMERGENCY AND RETURNED TO CLT. MAINTENANCE PERFORMED AMM TASK 26-10-00-810-811 AND WAS UNABLE TO DUPLICATE OVERHEAT FAULT. MAINTENANCE FOUND DUCT PRESSURE LOW ON ENGINE 1. REPLACED PRECOOLER CONTROL VALVE (AALA202109203131). REPLACED ENGINE 1 DAMAGED CORE FIRE DETECT HARNESS (AALA202109213228).