DTC P1361: Ic By-Pass Circuit: Notes

PCM provides Ignition Control (IC) spark timing on circuit. PCM correctly calculates optimum spark timing based on inputs received from several engine sensors. Engine load is calculated from MAF sensor, engine RPM is derived from 3X crankshaft position sensor, engine operating temperature from ECT and IAT sensors, and engine knock activity from knock sensor. Other engine functions modify spark to a lesser degree such as TCC engagement and EGR activity.

By-pass circuit controls an internal switch in electronic Ignition Control Module (ICM). By-pass circuit will have 5 volts applied to it unless vehicle is in back-up spark (base timing mode). This 5-volt signal from PCM allows a solid state switch to direct IC timing pulses to ICM for sequencing and energizing coil packs. If by-pass circuit is not energized, IC pulses from ICM are shunted to ground, and electronic ICM uses it's own base timing schedule to time and energize coil packs. Code will set if no pulses are detected on IC circuit by PCM.

1. Checks if conditions to set code are still present.
2. Checks for normal IC ground path through ignition module.
3. As test light touches IC by-pass circuit, module should switch, causing ohmmeter to overrange. The important thing is that module switched.
4. Module did not switch. This step checks for IC circuit shorted to ground, by-pass circuit open and faulty connections or module.
5. Confirms problem is faulty PCM and not an intermittent IC or by-pass circuit.