As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BOS - FLT 4843 - WHILE ON TAKEOFF, CREW RECEIVED A LEFT ENGINE FIRE WARNING. CREW OBSERVED THAT 'T' HANDLE LIGHT WAS NOT ILLUMINATED. CREW DETERMINED THAT THE WARNING WAS A SYSTEM FAILURE. TAKEOFF WAS ABORTED AND AIRCRAFT RETURNED TO THE GATE. MAINTENANCE REPLACED THE WEU AND SYSTEM CHECKED GOOD. AIRCRAFT RETURNED TO SERVICE. (M)