I am also in Chicago and I have this problem with AS error message as well as Dynamic Drive error message too. It only happens when really cold though. I say it must be some electronic gizmos because when it is warmer I have no such an issues at all. I know it sucks but in my car I drive for about 5 mins then when I turn the car off and restart again messages are gone. The funny thing is that those errors are not in cars computer memory later, as I talked to dealer about it and they found no fault codes.