What was found
NR 1 ENGINE ELECTRONIC ENGINE CONTROL BITE SHOWS FAULT CODE 77-20871, THE TOP LT EGT SIGNAL, T495S4 IS OUT OF RANGE. FAULT IS A LONG TERM FAULT AND IS LOGGED FOR 6 OUT OF THE LAST 10 STARTS. ACFT GROUNDED. ACCOMPLISHED T/S FOR FAULT 77-20871 IAW FIM 77-21, TASK 804. PERFORMED EGT CONNECTOR CLEANING IAW AMM 77-21-00-140-801, ALL CONNECTORS IN TABLE 2 CLEANED. AFTER CLEANING, T495S4 READINGS WERE STILL OUT OF LIMITS. R & R T495S4 PROBE IAW AMM 77-21-01-000-801, AMM 77-21-01-400-801. OPERATED ENGINE AND FOUND T495 READINGS WITHIN LIMITS WITH ENGINE RUNNING AND NOT RUNNING. PERFORMED EEC TEST IAW AMM 73-21-00-700-804-F00. NO FAULTS NOTED. EGT READINGS BEFORE CLEANING: S1-89.70; S2 - 53.32; S3-61.75; S4-119.59. AFTER CLEANING, AND PROBE REPLACEMENT: S1-116.28; S2-79.96; S3 - 84.98; S4-118.80.