As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMBOUT RECEIVED A LEVEL 2 ALERT FOR THE NR 1 ENGINE FIRE LOOP B AND TOOK THE APROPRIATE QRH ACTIONS (NO FIRE). TROUBLESHOT THE FIRE LOOP AND FOUND HIGH RESISTANCE TO GROUND. ALL OTHER 'B' LOOPS AND AIRCRAFT WIRING CHECK CLEAN. REMOVED AND REPLACED THE NR 1 PYLON FIRE LOOP B DETECTOR AND SECURED CONNECTOR P1-8692 IAW AMM 26-11-02-4. OPS CHECKED GOOD.