I have a 1998 Mercedes Benz C280 107,000 miles automatic. The BAS-ASR warning light on the dash cluster is on continually. Sometimes when starting the car it is off until I press the brake for the first time and then it stays on continually. I have had the battery checked and was advised it is OK. The problem started right after having my four snow tires removed. I have been told that scanning the diagnostic computer will not work as the engine light is not on, is this true? Can you tell me how to diagnose and repair this problem?