As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INTERMITTENT APU FIRE WARNING DETECTION LIGHT ILLUMINATING IN FLIGHT. AFTER LANDING ACCOMPLISHED FULL POWER DOWN OF ACFT. POWERED ACFT BACK UP & APU FIRE WARNING DETECTION LIGHT CONTINUES TO BE INTERMITTENT ON GND. R & R APU FIRE WARNING DETECTION SENSOR IAW AMM 26-11-02.