As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB AT 180 THE ENG 2 LOOP "A" LIGHT CAME ON WITH A SINGLE STROKE CHIME. THE ABNORMAL PROCEDURE WAS COMPLETED. TESTED GOOD AND LOOP "B" WAS SELECTED. REMOVED AND REPLACED #2 ENG FIRE DETECTION CONTROL UNIT AS PER MM 26- 12-11. OPS CHECKED GOOD.