Circuit Description

The Ignition Control (IC) module has independent power and ground circuits. The circuits between the IC module and the PCM consist of the IC timing signal, IC timing control, low resolution engine speed signal and a low reference signal.

The IC module sends 3X signals to the PCM. The IC module controls the timing advance during engine cranking. The timing advance changes to PCM control after the PCM receives the second 3X signal and after the PCM applies 5 volts to the IC timing signal circuit.