Ignition Control Module: Description and Operation

Ignition Control Module:

PURPOSE
Receives spark signals from the Powertrain Control Module (PCM) and serves as an electric switch for the coil primary circuit.

OPERATION
Based on input signals, the PCM will signal the Ignition Control Module (ICM) to make corrections to the basic engine timing. The computed ignition timing is determined by engine speed, intake manifold vacuum (calculated by the intake air amount and engine speed) and Exhaust Gas Recirculation (EGR) flow rate.