What was found
CREW RECEIVED A BRAKE OVERHEAT WARNING MESSAGE AND RT BRAKE TEMPS SHOWED THE INBD WAS AT 20. PERFORMED THE EMERGENCY CHECKLIST AND FOLLOWED PROCEDURES AND DECLARED AN EMERGENCY. DIVERTED AND LANDED WITHOUT INCIDENT. ACFT REMOVED FROM SERVICE. PERFORMED TROUBLESHOOTING FOR BRAKE TEMP SYS IAW FIM 32-46-00 AND FOUND NR 3 BRAKE TEMP SENSOR FAULTY. R & R THE BRAKE TEMP SENSOR ON THE NR 3 BRAKE IAW AMM 32-46-01. OPS CHECKED GOOD. ACFT RETURNED TO SERVICE.