Ignition Control Module: Description and Operation

Ignition Coil And Power Transistor:

PURPOSE
The Ignition Timing Control System operates by the ECU controlling the ignition timing through the power transistor. The ECU uses all of the engine condition and vehicle operating condition sensors (during normal driving conditions) to compute the correct spark advance or retard (during engine cranking, the ignition timing is fixed at 5°BTDC). The ECU uses the power transistor to control the ignition spark.

Component Overview:

LOCATION
Power transistor, located on the intake manifold under the ignition coils.

OPERATION
Controls the ignition timing by interrupting the ignition coil primary current ground causing secondary circuit discharge.


CONSTRUCTION
It is actually three power transistors combined into one unit, controlling each circuit of the ignition coils.