Hi
An OBD2 drive cycle is a series of tests that the vehicle runs. It resides in the area of the software of the ECM known as CARB (California Air Review Board) Readiness monitors. The monitors are like , EGR monitor , 02 monitor &
Catalyst monitor, Gasoline engines have evaporative monitors. In Emission testing States like Ca & others, they scan the computer to see if all the monitors have run.
This prevents people from merely clearling a Check Engine light and then going for a test , because many codes take a few start occurences to reset a light. Under normal circumstances it takes the average driver a day or 2 to run all the monitors be run and "ready" for testing. In rare cases the owner doesn't drive the right combinations of time & speed and it could take weeks to run the monitors. such as grandpa only drives 1 mile at 10 mph a day to get his lotto tickets. This can impact you if a dealer is checking your computer for reseting and clearing codes prior to going for for warranty work.
Charlie