As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENGINE FAULT CODE 75-10591 FOUND #1 ENGINE. TBV POSITION SIGNAL OUT OF RANGE. LONG TIME FAULT. DEFERRED PER T/C 78273000. GROUNDED - YES. T/S PER B737-900 FIM 75-23 TASK 802, PERFORMED EEC BITE PROCEDURE PER FIM 73-00 TASK 801 FOUND NO RECENT FAULTS AND NO FAULT ON FAULT HISTORY TECH SERVICES REPORT NO HISTORY.