Test 3: confirm VSS

The negative lead is left connected to pin 3, and the positive lead to pin 12 the VSS signal. This signal will be either a low (0V) or a high( 5V) when the car is stopped. As soon as the car begins to move, the signal will alternate between low and hi, and switch faster as the car moves faster. With the leads connected, engine running; push the car in neutral, or drive the car slowly, while watching the meter to confirm that the signal switches high and low. If it switches, the VSS connection is good.