As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TROUBLESHOOT FAULT MESSAGES ON APU HEALTH CHECK GEN FILTER. WHILE RUNNING APU, AUTO SHUTDOWN WITH GEN FILTER MSG. PERFORMED FIM 49-11 FT 969. REPLACED GENERATOR OIL FILTER AP SWITCH WITH OPS CHECK GOOD PER AMM 49-27-15. GROUND VERIFIED AND AC REMAINS ETOPS 180.