Ignition Control Module: Description and Operation

PURPOSE
The Ignition Control Module controls spark ignition and duration.

OPERATION
Receives PIP signal to determine crankshaft position and engine speed. PCM uses PIP signal and other inputs to determine appropriate ignition timing. ICM controls ignition coil to achieve correct dwell and spark timing. Also generates Ignition Diagnostic Monitor (IDM) signal for PCM to monitor ignition system. Used by the PCM in determining EPC pressure and shift scheduling.