What was found
FL380 EMERGENCY DECENT WARNING PAX OXY DPLY PRESSURIZATION SHOWED NORMAL INDICATIONS. PERFORMED EFIM SOLUTION FOR FAULT CODE 2190F0036 (10 # 1-04489), CPCS BIT CHECK AND CABIN PRESSURE RELAY CHECK OK. NO FINDINGS. AS PRECAUTION REPLACED IASC 1 AND 2, ORDERED IASCS (WIP EB 781199) DOWNLOADED FDR DATA REF A220 AMP 31-31 (BB 296757) REMOVED AND INSTALLED IASC 1 AND 2 REF A220 AMP 21-90 REF A220 IPDP 21-90-01-0AAA-941A-A ITEM #10 (BB 296757). VERIFIED ALL MAINTENANCE C/W PER RESPECTIVE M/M'S AND CHECKS GOOD. (LP# 4345424, 4345430)