The OBD II portion of the smog check can not be disabled. Your BMW has to undergo the OBD II test and must have it's "Emission Monitors" in "ready" condition in order to pass the smog check. The only way of accomplishing this is to drive your BMW as you've mentioned... at least 100 miles with several starts and stops, in both city and highway traffic.
To be safe we recommend one weeks worth of driving (at least 200 miles). If your vehicle fails the smog check re-test, you'll need to have a smog check repair station diagnose the reason why the emissions monitors are not setting as required.
posted by SmogTips Support