98 e320 resetting OBD codes

I replaced my Air Mass Control Sensor and had an independent shop "reset" the "check engine" light.
Unfortunately, I then took the car to DEQ (in Oregon) and it failed the emmissions test due to lack of data and codes not being "ready" on the some of the systems.

I was told there is a "drive sequence" that will reset all of them.
Please let me know:
1. how to perform the "drive sequence"
2. how to reset the check engine light so that I will not have to pay again, next time the thing goes off.

Thanks,
Mark