My check engine is OFF but my catalyst monitor in NOT resetting!

If you have had the battery disconnected, ecm disconnected, or software done to the car recently I have seen it take up to 500 miles to set. Usually it takes about 100.

a 2005 Volvo monitoring system needs about 40-50 miles to reset, its a driving cycle with a special ways how to drive the car to have it reset properly, 55 miles per hour even speed, it might need also a one cold start to re set system properly.