Ignition system of ignition gasoline engine is usually composed of power supply (battery, generator), ignition switch, starter (additional resistor switch), capacitor, power break - distributor, ignition coil, additional resistance, high pressure line, spark plug and so on. Failure of the ignition system makes the engine work abnormal or even unable to start, which directly affects the transport effect. Therefore, timely judgement and removal of ignition system faults is of practical significance to ensure the normal operation of the vehicle.