if you have the car and a balancer you can put through the cas and turn refer to the gregorys manual for testing procedure it tells you how to test it but you need a test light and a couple of jumper wires and the dfi module connected so your just going to have to plug it on the sensor harness on the car too test it I thought the book would show a resistance value but the hall effect sensor must be open circuit when its off so no multimetre test or something like that