As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RETURNED TO ORD DUE TO NR 2 ENGINE OVERHEAT INDICATION LIGHT. MAINTENANCE PERFORMED TROUBLESHOOTING OF THE NR 2 OVERHEAT DETECTION SYSTEM AND REPLACED M1121 LOWER FAN "A & B" LOOP OVERHEAT DETECTORS. AFTER REPLACEMENT, NR 2 ENGINE OVERHEAT DETECTION SYSTEM TESTED NORMAL.