Operation CHARM: Car repair manuals for everyone.

Ignition Control Module: Description and Operation

IGNITION CONTROL MODULE
The Ignition Control (IC) module performs several functions:

^ It monitors the "ON-OFF" pulses produced by the two crankshaft and one camshaft position sensors.
^ It creates a 4X and 24X reference signal (4X REF HI and 24X crank) sent to the PCM for ignition control.
^ It creates a camshaft reference signal (CAM HI) 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 IC module is not repairable. When a module is replaced, the remaining components must be transferred to the new module.


The PCM uses IC module information for fuel control, idle speed control and ignition control (which it outputs back to the IC module). A fault with any of these signals between the IC module and PCM will cause various driveability conditions and should set a DTC.