As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU DETECTOR LIGHT ON INTERMITTENLY WITH APU OFF DURING TAXI OUT. APU DETECTOR LT ON SOLID. CONTROL MODULE M279 SHOWS APU TAIL PIPE DETECTOR FAULT. REF MM 26-15-01, R & R APU OVERHEAT DETECTOR ELEMENT ASSY (TAIL PIPE). OPS NORMAL REF SAME MM/ OPS TEST 26-15-00.