As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU WILL NOT START. APU HANGS BETWEEN 27-40 PERCENT AND BATTERY DISCHARGE AT START SEQUENCE NORMAL, RESET OF ECU ALLOWS FOR NORMAL START. TROUBLESHOT IAW 49-61-00. REPLACED ECU AND STARTER IAW AMM. APU START NORMAL. APU CONTROLLER MR49613 OFF-43 ON-122. STARTER MR49408 OFF-18 ON-5.