Ignition Control Module: Description and Operation
OPERATIONWhen the ignition power transistor is turned ON by the signal from the engine control module, primary current flows to the ignition coil. When the ignition power transistor is turned OFF, primary current is shut off and a high voltage is induced in the secondary coil.
When the engine control module turns OFF the transistor in the module, the battery voltage in the module is applied to the ignition power transistor unit to turn it ON. When the engine control module turns ON the transistor in the module, the ignition power transistor unit is turned OFF.