As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
GE DIAGNOSTICS REPORTS #1 ENGINE TREND DATA SHOWS A LARGER THAN NORMAL AMOUNT OF SCATTER AND EGT HDM DECREASE. EGT INDICATION ERRORS ARE SUSPECT. GROUNDED - YES. REMOVED AND REPLACED ENGINE #1 J10 HARNESS REF B737-800 AMM 73-21-06-400-802-F00. REPLACED ENG #1 S3 PROBE REF AMM 77-21-01-400-801-F00.