1. Key/Button Activation: Turning the key to the "off" position (or pressing the stop/start button) breaks the electrical circuit that provides power to the ignition system. This is the primary initiating event.
2. Ignition Switch: The ignition switch is a mechanical or electronic component that directly controls the flow of power to various parts of the car, including the engine control unit (ECU). Turning the key physically interrupts this power flow. In modern cars with push-button start, it's an electronic signal that accomplishes the same thing.
3. Engine Control Unit (ECU): The ECU receives the signal that the ignition is off. It then sends signals to various components to cease operation.
4. Fuel Pump: The ECU shuts off the fuel pump, stopping the supply of fuel to the engine.
5. Ignition System: The ignition system (spark plugs, coil packs etc.) is deactivated, preventing the creation of sparks needed for combustion.
6. Injector Shut-off: Fuel injectors cease injecting fuel into the cylinders.
7. Crankshaft Stops Rotating: With no fuel and no spark, the engine's momentum gradually decreases until the crankshaft comes to a complete stop.
In short, it's a coordinated shutdown controlled by the ECU, initiated by the act of turning the key or pressing the start/stop button, cutting off the crucial elements needed for engine operation.
