I have a CPU that stops communicating to the service tool. In this case a genuine Mont.tool. The tool works fine with the other units in the MR. I tried swapping the EE prom with intial success then failure. The car will run but stops communicating with the tool. If you log out it cannot reestablish communication. This is particularly annoying after you inhibit the doors.I have tried two other CPUs. My next guess is the two static ram chips. I wouldn't think the board would work at all in this case. Any thoughts from you guys?