DIS Interface

Ignition System Wiring.:

The PCM supplies two signals to the ignition module. One signal is an ignition timing waveform, and the other signal is a fail-safe discrete signal that informs the ignition module that the PCM is operational. The rising edge of the timing waveform indicates the beginning of the spark event. The timing waveform is a 0 to 5 volt variable duty cycle, and frequency, based on the engine waveform and is generated by the PCM to indicate spark advance.

The discrete signal is a constant five volts while the PCM is operational and must be at ground when the PCM is not operational.