As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU "FAULT" LIGHT WHILE ATTEMPTING START. GROUNDED - YES. IN OMF FOUND MAINT MESSAGE 49-41254 START CONVERTER UNIT SHOWS START SYSTEM INOP. PERFORMED GVI OF CONNECTOR P6 REF B737-9 AMM 49-11-01 AND B737-9 IFIM 49-40-00-810-818. NO DEFECTS NOTED. STARTED AND RAN APU 5 TIMES WITH NO FAULTS NOTED. APU STARTS AND OPERATES NORMAL.