As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU BOTTLE LOW/CHECK FOR DEFECT/MASTER WARNING COMES ON INTERMITTENTLY DURING FLIGHT. MAINTENANCE INSPECTED THE AIRCRAFT AND CLEANED AND RESECURED THE CONNECTOR. THE MASTER WARNING CLEARED. OPERATIONAL CHECKS WERE GOOD AND THE AIRCRAFT WAS RETURNED TO SERVICE.