Ignition Control Module: Description and Operation

The Igniter, inside the distributor assembly, is a computer controlled switching device that turns the ignition coil primary circuit "ON" and "OFF" to fire the coil.

A low voltage signal from the ECU turns the igniter "ON". In this "ON" state, the igniter completes the coils primary circuit to ground, allowing current to flow through the coil. When the low voltage signal is interrupted, the igniter turns "OFF" interrupting the ignition coil primary circuit and causing the coil to discharge.

Ignition timing is determined by the ECU depending on inputs from these engine sensors:

^ Distributor Ne signal
^ Distributor G signal
^ Water thermosensor
^ Airflow meter
^ Atmospheric pressure sensor
^ EC-AT control unit
^ Knock sensor
^ Throttle sensor/idle switch
^ Ignition switch ("START" position)
^ A/C switch
^ EGR position sensor
^ Test connector (for base timing adjustment)