As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENGINE #1 FAULT CODE 73-21701. ADIRU TAT DATA AND THE T12 SIGNAL DISAGREE. SHORT TIME DEFERRED PER ASA T/C 78273000. GROUNDED - YES. T12 SENSOR CHB PINS 1 TO 2 OPEN REF B737-800 FIM 73-28 TASK 801 TABLE 201. REPLACED T12 SENSOR, EEC TEST PASS B737-800 AMM 73-21-05. REPAIR CONFIRMATION SUCCESSFUL PER SAME.