Ignition Control Module: Description and Operation
DESCRIPTION AND OPERATIONIgnition Control Module (ICM):
The Ignition Control Module (ICM) is a microprocessor-based device with coil drivers which make decisions about spark timing and coil firing and performs the following:
1. Receives engine position and speed information from the Crankshaft Position (CKP) Sensor, and desired spark advance information from the Powertrain Control Module (PCM).
a. The ignition control module uses this information to determine which ignition coil to fire, calculating the turn ON and OFF times of the ignition coils required to achieve the correct dwell and spark advance.
2. Outputs a Profile Ignition Pickup (PIP) signal and an Ignition Diagnostic Monitor (IDM) signal for use by the powertrain control module.
3. Sends information on system failures through the IDM signal to the PCM and stores information for use during diagnostic test mode. The IDM also provides the signal for the tachometer.