As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE PERFORMING TASK CARD 78273000, #1 ENG HAS SHORT TIME FAULT 73-30351 THE FMV POSITION SIGNAL DISAGREE, ON MULTIPLE FLIGHT LEGS. GROUNDED - YES. ACCOMPLISHED B737-800 FIM 73-25 TASK 804, ALL CONTINUITY CHECKS GOOD. REMOVED AND REPLACED HMU PER TASK CARDS N8473000/N8473001. NO LEAKS NOTED.