Ignition Control Module: Description and Operation

Power Transistor:

PURPOSE
Activates the primary circuit in the ignition coil.

LOCATION
Located between the distributor and the ignition coil.

OPERATION
The power transistor is a low current switch. It allows the signal sent from the PCM (very low current) to activate the primary circuit in the ignition coil (much higher current). This induces high voltage in the secondary windings of the ignition coil, providing spark to the distributor cap and plugs.