The car is a '95 Caprice 9C1 and I have used this scan tool many times before on this car, but now it can't communicate with the car. I used the scan tool recently on a 2001 OBD II car so I know the scan tool is not dead but maybe the OBD I part is dead. The diagnostic connector under the dash looks OK and the wiring to it (only 3 wires) looks OK. I searched the list of fuses in the owner's manual and I did not find any description that mentioned the diagnostic connector. Is there a fuse that could cause this problem? I don't know if the problem is in the car or in the tool. If I can try the tool on another (borrowed) OBD I car, is there a chance that the scan tool could damage the car? If I can borrow another OBD I scan tool, is there a chance my car could damage the tool? The car is drive-able. It is stumbling some at low rpms and I wanted to check for trouble codes.