The COP sensor is used to look at the health and overall performance of a coil on plug ignition systems. The probe is used to determine whether the ignition system is able to provide sufficient spark energy (and duration of the spark) for the current operating condition of the vehicle.
The COP sensor transforms the signal induced into it by the ignition coil’s high-voltage chain into a voltage pulse, which are shown on the oscilloscope’s screen. These values are in direct relation to the voltaic arc produced by the spark plug. Because of the variety of ignition coils with different types of construction, it should be noted that the COP sensor cannot determine the exact value of the voltage where the ignition spark appears, but it can be used for a comparative analysis between the different cylinders in order to determine which cylinder is not working properly.