As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE ACCOMPLISHING T/C 78273000 - FMC CDU ENG FAULTS NR 1 ENG LOGGED FAULT CODE 73-31611 - ADIRU2 DATA FROM DEU IS MISSING. ACFT GROUNDED. REMOVED NR 1 ENG EEC REF AMM 73-21-60-000-801-F00. INSTALLED SERVICEABLE EEC, REF MM 73-21-60-400-801-F00 STEPS 3.E.(1) - 3.F.(2) COMPLETED MM73-21-60-400-801-F00. POWERPLANT REF TABLE TESTS NORMAL REF MM 71-00-800-811-F00. EEC TEST NORMAL REF MM 73-21-00. ETOPS GROUND VERIFICATION SUCCESSFUL.