As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RIGHT ENGINE EGT INDICATION PROBLEMS. RIGHT ENGINE EGT INDICATION VERY ERRATIC. FLIGHT 0945-03 FRA-ORD, DIVERTED TO LHR. WIRING CHECKS PIN-TO-PIN, AND PIN-TO-GROUND ACCOMPLISHED OK. CONTINUITY CHECKS NORMAL. REPLACED WO623 HARNESS PER AMM 73-21-73. (PW IPC 73-21-00-21-001). ACCOMPLISHED TESTS AND HIGH POWER RUN - EGT STEADY, CHANNELS A & B READ THE SAME. THE TIMES GIVEN BELOW FOR THE REMOVED HARNESS ARE ESTIMATED.