As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING HEAVY MAINTENANCE, AFT CTR 02 BOX FAILED OPS TEST; (RESOLVED ON W/O: 1473121 TASKCARD: NR-00047 ) REF AAR WO 440624 NR 30769 TROUBLESHOOT AND REPAIRED AFT CENTER O2 BOX IAW AEROSPACE CMM 35-21-74. CRI ACCOMPLISHED ON NR 30823. OPS CHECK GOOD IAW AMM 35-23-00-710-001-A.