Erase memory in 4MATIC
 

Does any one knows how to erase the memory of the 4matic, except for removing the positive of the battery for 15 minutes or bringing the car to a mechanic to connect to the computer. I am looking for a home made device of some sort. I would like to do that because the problem is intermitent and when I erase the memory the system works fine for a few days and then fails again. those few days would be enough to get me trough a snow storm or a difficult situation when they happend. The rest of the time I do not really need the 4 wheel traction. Also the system never fails while I am driving, only when I sart the car after being parked. I had the car check for mechanical failure and my mechanic assure me everything is fine, it is just a sensor playing game on us, presumedly the steering wheel sensor.