As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON APU START, ITT GAGE INDICATED 999 DEGREES AND RED, APU WOULD NOT SHUT DOWN. COMPLIED WITH QRH EMER 5-2 AND DISCHARGED APU FIRE EXT CONTACTED FIRE DEPT, THEY REMOVED APU PANEL AND VERIFIED NO FIRE IN APU ENCLOSURE. DOOR POSITION VERIFIED CLOSED. R & R APU FIRE EXTINGUISHER AND SQUIB IAW AMM 26-22-02. OPS CHECK GOOD, DMIL CLEARED, PLACARD REMOVED.