As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
GE DIAGNOSTICS REPORTS NR 1 ENGINE TREND DATA SHOWS A SUDDEN SHIFT IN EGT HOT DAY MARGIN ALL OTHER PARAMETERS NORMAL. EGT INDICATION ERRORS ARE SUSPECT. PERFORMED FMC CDU FAULT TC 78273000 NO RECENT FAULTS FOUND. FOUND CJ10 HARNESS S3-S4 CONNECTORS HAD CORRODED CONTACTS AND DISCOLORED INSULATORS. REPLACED CJ10 HARNESS REF MM 70-20-03 AND WDM 77-21-11.