As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON SERVICE CHECK FOUND APU FIRE DETECTION WOULD NOT TEST. PLACED APU FIRE DETECTION ON DMI, CONTROL NR 8834, CAT C, PER DHL MEL 26-11. C/W SP 26-11. 8834-APU FIRE DETECTION WILL NOT TEST. REMOVED AND REPLACED OPERATING POWER UNIT. PERFORMED TEST IAW 26-15-00B727MM. OKAY . THIS CLEARS DMI 8834.