As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
L/R UTILITY BUS LIGHTS ON. UNABLE TO RESET ACCURED AFTER T/O T/S BPCU AND FOUND FAULT CT LOOP GND FAULT IN APU POWER SYSTEM PART OF TEST. FIM FOR CT LOOP GND STATES TO REPLACE APU GENERATOR CONTROLLER. REPLACED BPCU, TEST PASSED, SYSTEM OK FOR SERVICE.