As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER LEAVING GATE ON ENGINE START, GOT EICAS MSG LT ENG CONTROL. MTC IN PROGRESS. FOUND LT ENG PIMU MSG 155-23. TRIED RESET NO HELP. REPLACING HMU REPLACED HMU IAW MM LK CK GOOD A/C OK FOR SVC. ETOPS CATEGORY (E): PROBLEMS WITH SYSTEMS CRITICAL TO ETOPS