Ignition Control Module: Description and Operation

PURPOSE

The power transistor controls ignition current by interrupting the ignition coil primary ground causing secondary circuit discharge.

OPERATION

When 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.