As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FOLLOWING NORMAL ENGINE START MASTER CAUTION ILLUMINATED WITH NR 1 ENGINE CONTROL LIGHT. NO OTHER ABNORMAL ENGINE INDICATION. BITE TEST NR 1 ENG AND FOUND MSG 75 20581 TBV POSITION SIGNAL AND DEMAND SIGNAL DISAGREE. ACCOMPLISHED FIM TASK 75 23 00 810 801 F00 AND MM 71 00 00 700 807 F00. TEST PASSED. MAINT CONTROL AND TECH SVC. ADVISE TO CHANGE NR 1 ENG HMU 16330. INSTALLED NEW HMU PER MM 73 21 10 400.