The ignition control modules (ICM) is located on top of
the front and rear camshaft covers under the ignition coils. The
ICM performs sever functions:
| • | It monitors the on-off pulses produced by the tow crankshaft and
the camshaft position sensor. |
| • | It crates 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.
