As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CSS APU START FAILED DUE TO OVERTEMP TO 1000 DEGREES, RESULTING IN AUTO SHUTDOWN WITH FAULT LIGHT. ACFT GROUNDED. REMOVED & REPLACED THE APU FCU IAW AMM 49-31-11, LEAK CHECKED & GROUND FUNCTIONAL CHECKED NORMAL IAW APU BITE TEST TASK 49-61-00-700-801.