Ignition Control Module: Description and Operation

The ignition control module receives the signal from the Powertrain Control Module (PCM) to fire the coil. It is part of the distributor and is not serviced separately.

The Ignition Diagnostic Monitor (IDM) is a function of the ignition control module. The ignition control module sends information on system failures to the PCM, which stores the information for diagnostic self test. The IDM signal is also used to drive the tachometer.