As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING ENGINE START AFTER BOTH PACKS TURNED OFF THE APU SHUTDOWN WITH A FAULT LIGHT. ECU MINI FLAGS WERE 12-37-43. FWD APU PNEUMATICS FUNCTION TO MEL 49-11-01C. MCO/PLAC INSTALLED. OPS CHKD APU ON ARRIVAL OPERATES OK DID BITE CHK SHOWS REPLACED ECU. ECU BITE CHKS GOOD PER AMM 49-61-06. MCO PLACARD REMOVED.