Ignition Control Module: Description and Operation

Ignition Coil And Power Transistor Circuit:

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

Component Overview:

LOCATION
The power transistor is located on the intake manifold.

OPERATION
The ECU controls ignition timing through the power transistor. The power transistor is a type of switch that allows a very low Voltage (from the ECU) to control a larger amount of Voltage (negative side of coil). During engine cranking, the ignition timing is fixed at 5°BTDC