Ignition Switch ON (Engine Off) Mode

When the ignition switch activates the fuel injection system:
1. The PCM determines atmospheric air pressure from the MAP sensor input to determine basic fuel strategy.

2. The PCM monitors the engine coolant temperature sensor and throttle position sensor input.
- The PCM modifies fuel strategy (injector pulse width) based on this input.

When the key is in the ON position and the engine is not running (zero rpm):
The auto shutdown relay and the fuel pump relay are not energized.
- Therefore, voltage is not supplied to the fuel pump, ignition coil or fuel injectors.