Igniter : The igniter is used by the car’s ignition system to turn a coil on and off quickly using a transistor. It is ultimately controlled by the crank sensor, cam sensor or distributor pickup which sends it a series of pulses as the reluctor pattern passes by it. This is similar to an ignition module’s role on an ignition system. A typical igniter may contain resistors, diodes and a control chip to sense the crankshaft position and deliver a proper signal conversion to the ignition coils.
Not all automotive applications contain an igniter. When an igniter fails, the ignition system will not properly convert the crank signal to the coil signal. This will cause a no spark situation to 1 or more coils depending on the make and model. Igniters can sometimes be ohmed out to test otherwise, they need to be replaced to verify the problem. An igniter is usually one of the last components that fail in an ignition system.