Code P023, Ignition Control Circuit Problem: Notes

Ignition spark is controlled by PCM and ignition control module. Code P023 will set if reference pulses are being received by PCM and bypass line is low, and PCM detects pulses on ignition control line. This could be caused by by-pass line shorted to voltage at distributor. Code P023 will also set if reference pulses are being received by PCM and by-pass line is high, and PCM does not detect a signal on ignition control line. This could be caused by an open or shorted to ground ignition control line or by-pass line.