What was found
ON DEPARTURE OUT OF MEM AT 3,000 VERY STRONG ODOR IN COCKPIT / TURNED BACK TO MEM. ON DESCENT TO 3,000 ODOR CAME BACK. AVIONICS FLOW LIGHT CAME ON DURING DEPT. FOLLOWED ECAM SELECTED, OVERBOARD. REMOVED AND REPLACED ISOLATION VALVE PER AIR BUS MM 21-23-12-4. OPS CHECK GOOD. R/I FROM FACT PREMATURE REMOVAL/INSTALLATION OFF MFG B38QA6505, POS P2 SRL 2014, TAG 999062 ON MFG B38QA6505 SRL 102, TAG 265720.