Skylark V6-191 3.1L VIN M SFI (1994)
Ignition Control Module: Description and Operation
Typical Ignition Module Assembly
PURPOSE
This Ignition Control (IC) module, mounted above the valve cover at the rear of the engine compartment, monitors the crank sensor signals and, based
on these signals, sends a reference signal to the PCM so that correct spark and fuel injector control can be maintained during all driving conditions.
OPERATION
During cranking, the IC module monitors the "sync pulse" to begin the ignition firing sequence and below 400 rpm the module controls spark advance
by triggering each of the three coils at a pre-determined interval based on engine speed only. Above 400 rpm the PCM controls the spark timing
through Ignition Control (IC), and compensates for all driving conditions. The IC module must receive a "sync pulse" and then a crank signal in that
order to enable the engine to start. The IC module is not repairable. When a module is replaced, the ignition coils must be transferred to the new
module.
