As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI CREW REPORTED ,APU DOOR STATUS MESSAGE APPEARED AFTER TAXI A/C RETURNED TO GATE (BTB) AND MTX GROUNDED A/C. MTX PERFORMED TROUBLESHOT IAW FIM 49-11 FAULT TREE 988. NO DEFECTS NOTED. OPS CHECK GOOD.MTX REURED A/C TO SERVICE .