As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MASTER WARNING: CHECK FIRE DET AND APU FAULT LIGHTS ILLUMINATED DURING FLIGHT AT CRUISE . OUTSIDE TEMP -40°C. BOTH LIGHTS EXTINGUISHED DURING DECENT. REMOVED FROM SERVICE. PERFORMED GVI OF APU & LOOP FOR ANY DAMAGE OR DEFECTS. NO DEFECTS FOUND. ACCESSED CDS (APU) FOR FAULTS NO FAULTS FOUND. PERFORMED A FIM TASK (PER MTX) 26-10-00-810-801, FOR OPERATIONAL TEST OF APU & NACELLE FIRE DETECTION SYSTEM. REF STEPS 3 A ( 1&2). NO DEFECTS NOTED. RETURNED TO SERVICE. NO PARTS REPLACED.