As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU WOULD NOT START TWO ATTEMPTS, HUNG UP AT RPM 18. BITE APU ECU NO FAULTS NOTED. ON TEST FOUND APU IGNITION INOPERATIVE. R & R APU IGNITION EXCITER & IGNITER PLUG. APU START NORMAL & OPS CHECKED GOOD. OK FOR SERVICE IAW AMM 49-41-03-049-41-02.