Ignition Control Module: Description and Operation

Power Transistor Testing:

PURPOSE
Activates the primary circuit in the ignition coil.

LOCATION
On the front cylinder head.

OPERATION
The power transistor unit is a low current switch. It allows the signal sent from the ECU (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 plugs. There are six power transistors in the unit.