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Ignition Control Module: Description and Operation

IGNITION COIL AND ICM

The ICM is connected to the PCM by an ignition control (IC) circuit. The ICM also has a ground circuit and shares an ignition 1 voltage supply with the ignition coil. The coil driver in the ICM controls current through the ignition coil based on signal pulses from the PCM. There is no back-up or by-pass function in the ICM.