Pico cop probe pp338 pico pp338 designed to save you time effort and money the pico coil on plug ignition probe is the fastest way to test both conventional and coil on plug secondary ignition systems the probe eliminates the need for back probing or any dismantling to use the probe simply press it against the coil it is the fastest way you can check coil on plug ignition coils and spark plugs br br like distributors spark plug wires are starting to disappear from cars with the new