As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU FAULT LT ON APU START. GROUNDED - YES. CHECKED AND FOUND FAULT MESSAGE 49-89002 "ONBOARD MAINTENANCE FUNCTION HAS NO INPUT FROM APU ECU". FOLLOWING B737-9 IFIM TASK 49-00-00-810-817 FOR APU NO INPUT FROM APU ECU CODE 49-89002. PERFORMED RE-RACK OF APU ECU IN REFERENCE WITH IFIM TASK 49-00-00-810-817, OPS CHEK GOOD. OMF SHOWED NO FAULTS.