As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
#1 ENG O/H DET LOOP "B" WILL NOT TEST. GROUNDED - YES. FOUND CORE DETECTOR RH TO HAVE A BROKEN TERMINAL LUG. RE-TERMINATED PER B737-800 AMM 26-11-02-960-801. PERFORMED AN ENGINE FIRE DETECTION OPERATIONAL TEST PER AMM 26-11-00-710-801. CHECKS GOOD. ALTERNATE DEACTIVATION PROCEDURES REVERSED. ONE CB WAS PULLED AND RESET. ETOPS GROUND VERIFICATION WAS SUCCESSFUL.