As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE WORKING TC 78273000 - ENG #1 FAULT CODE 75-10401. VSV SIGNALS DISAGREE (POSITION). SHORT TERM FAULT. DEFER PER TC 78273000. GROUNDED - YES. REFERENCE LOGPAGE 60269685 REMOVED AND REPLACED J9 AND J10 HARNESSES REF B737-800 AMM 73-21-06-400-802-F00 STEPS E(1,2). PERFORMED FADEC TEST REF AMM 73-21-00-700-802-F00 STEPS (D) 3.A,B,C AND E. PERFORMED REPAIR CONFIRMATION REF B737-800 FIM 75-33 TASK 805. PERFORMED ACTUATORS TEST REF AMM 71-00-00-700-807-F00, ALL TESTS PASS, ETOPS GROUND VERIFICATION SUCCESSFUL.