Ignition Control Module: Description and Operation

The Ignition Control Module (ICM) is a switching device located in the distributor which performs several functions:

^ It monitors the "ON-OFF" pulses produced by the magnetic pickup assembly.

^ It creates 1X reference signal (1X CRANK) sent to the Powertrain Control Module (PCM) for ignition control.

^ It provides a means for the PCM to control spark advance (BYPASS and IGN-ON CONTROL) called "Ignition Control Mode."

^ It provides a limited means of controlling spark advance without PCM input called "Module Mode."