Ignition Circuit Sense

PURPOSE

Signal indicates to the Powertrain Control Module (PCM) that the ignition circuit is energized, and the engine is being rotated, (by combustion or the starter motor).

Based on this information the PCM decides whether or not to energize the fuel pump, fuel injectors, ignition coil(s) and oxygen sensor heater element.

OPERATION

When the key is in the on position, the PCM constantly monitors the ignition circuit.

- A pulsed signal at this input indicates that the ignition system has been activated by the ignition switch, and the distributor is rotating.

- When a signal is being received the Powertrain Control Module (PCM), the PCM energizes the Auto Shutdown (ASD) and fuel pump relays. When these two relays are energized, battery voltage is supplied to; the fuel injectors, fuel pump, ignition coil(s) and oxygen sensor heater.