What was found
GEG FLIGHT NR 2371: CABIN HOT DUCT CAUTION LIGHT ON. DUCT TEMP IN NORMAL RANGE. AIRCRAFT RETURNED TO GATE. MAINTENANCE C/W FIM TASK 21-60-00-810-804. ECS FAULTS CLEARED AND CAUTION LIGHT EXTINGUISHED. CABIN DUCT TEMP NEVER INDICATED ABOVE NORMAL ON TEMP INDICATOR. ORIGINAL FAULT CODE 4101 ECU ANLG CH-1 NEVER REAPPEARED. AFTER OPS CHECK OF ECS TEMP CONTROL SYSTEM. NO PARTS REPLACED. AIRCRAFT RETURNED TO SERVICE.