1998 Volvo V70 engine light

if you can not clear it with the scan tool, then let it go through the drive cycles to clear, usually about 50 starts, (now dont go sitting in your back yard starting the car fifty times to see if it goes out lol). seriously, what Is bothering me is , you said the scan tool "cannot communicate with the ecm, that usually means the connection is bad or the ecm is faulty, but lets not go there right this second, give it sometime to go throught the drive cycles, it may not even be fifty times it could be much less, but that is a maximum figure(.LIke if it doesnt go out by fifty it will never go out). give it a chance , keep me posted.