As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING ASA TASKCARD #78273000 FOUND FAULT CODE 77-20871 "THE TOP LEFT EGT SIGNAL (T49554) IS OUT OF RANGE" LONG TIME FAULT. GROUNDED - YES. REMOVED AND REPLACED CJ10 HARNESSREF B737-900 AMM 73-21-06. FADEC SYSTEM TEST OK. [REF ASA LP 60398279]