Ignition Control Module: Description and Operation

Ignition Control Module:

The Ignition Control Module (ICM) receives spark signals from the Powertrain Control Module (PCM) and serves as an electric switch for the coil primary circuit. Based on input signals, the PCM will signal the ICM to make corrections to the basic ignition timing. The computed ignition timing is determined by the engine speed, intake manifold vacuum (calculated by the intake air amount and engine speed) and Exhaust Gas Recirculation (EGR) flow rate.