As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT#20, LHR-JFK. (ETOPS) 'ENG 2 FIRE LOOP A FAULT ( ENGINE FIRE DETECTION SYSTEMS 1) LOOP A ); REF L/P 3812193-1 FOR REPLACEMENT OF (4002WD1) AND REF L/P 3812193-2 FOR REPLACEMENT OF FIRE ELECTRIC HARNESS AND REF L/P 3812195-2 (REPLACED FIRE ELEC HARNESS AS PRECAUTION IAW AMM 26-12-61. OPS TEST GOOD. ITEM REMAINS OPEN FOR FUTHER TROUBLESHOOTING) FOR REPLACEMENT OF ( 4001WD1) FIRE OVERHEAT DETECTOR. OPS CHECK ALL GOOD. NO FAULT PRESENT; THIS CLEARS MDDR 533900. PLACARD REMOVED.