As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU FAILED TO START AT GATE. WO MESSAGES FAULT CODE 491-004-00 MAINT MESSAGE 49-18801, AND FAULT CODE 491-004-00 MAINT MESSAGE 49-10620 FAULT HISTORY. REPLACED ELECTRIC STARTER MOTOR AND APUC. VERIFIED 28 VOLTS TO STARTER, REPLACED COMPONENTS, OPS CHECK GOOD.