As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING AIRCRAFT OPERATIONS THE FLIGHT CREW REPORTED THE APU WAS INOP. THE APU FAULT WAS DEFERRED BY MEL AND THE FLIGHT CONTINUED. THE MAINTENANCE VENDOR TROUBLESHOT AND DETERMINED THAT THE APU CONTROL UNIT HAD FAILED. THE DEFECTIVE ECU WAS REMOVED AND A TESTED UNIT WAS INSTALLED. THIS ACTION CLEARED THE MEL AND THE AIRCRAFT WAS RETURNED TO SERVICE.