System Description

The ignition control module (ICM) is located on top of the rear camshaft cover. The ICM performs sever functions:
^ It monitors the on-off pulses produced by the tow crankshaft and the camshaft position sensor.
^ It creates a 4X and 24X reference signal (4X ref high and 24X crank) sent to the PCM for ignition control.
^ It creates a camshaft reference signal (1/2X cam high) sent to the PCM for fuel injection control. It provides a ground reference (ref. lo/cam lo) to the PCM.
^ It provides a means for the PCM to control spark advance (bypass and ignition control), called ignition control mode.
^ It provides a limited means of controlling spark advance without PCM input, called module mode.
The ICM is not repairable. When a module is replaced, the remaining components must be transferred to the new module.