As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU FAULT LIGHT ILLUMINATED DURING APU START. APU WOULD NOT START AFTER FOLLOWING QRH. ACFT GROUNDED. APU BITE DONE IAW AMM 49-61-00-700-801. FAULT CODE 49-41011 FOUND. CONNECTOR P13 DISCONNECTED AND CHECKED FOR POWER IAW WDM 49-41-11. POWER CHECKED GOOD. REPLACED THE IGNITION UNIT IAW AMM 49-41-31, AND AS A PRECAUTION, REPLACED THE IGNITER PLUG AND LEADS IAW AMM 49-41-51 AND 49-41-52. APU OPS CHECKED NORMAL, NO DEFECTS NOTED.