As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU WILL NOT START. FAULT LIGHT ILLUMINATED. ACFT GROUNDED. APU BITE TEST SHOWS FAULT CODE 49-41180, IGNITION CIRCUIT SHOWS HIGH CURRENT. REPLACED THE APU IGNITION UNIT IAW AMM 49-41-31 AND FIM 49-40, TASK 804. OPS CHECK GOOD WITH 4 SUCCESSFUL STARTS.