Circuit Description

Ignition Control Module (ICM) sends signals that PCM requires for fuel control and spark advance calculations. At start of engine crank, ICM controls spark advance (by-pass mode). When second 3X signal is recognized by PCM, it applies 5 volts to by-pass circuit, commanding ICM to switch Ignition Control (IC) of spark advance to PCM (IC mode). An open in IC circuit, or a short to voltage in by-pass circuit will set DTC 1350.

Condition required to set DTC is:

• PCM monitors IC pulses during crank while by-pass mode spark advance is commanded.