Operation CHARM: Car repair manuals for everyone.

Ignition Switch ON (Zero RPM)

When the multi-port fuel injection system is activated by the ignition switch, the following actions occur:
- The PCM determines atmospheric air pressure from the MAP sensor input to determine basic fuel strategy.
- The PCM monitors the coolant temperature sensor and throttle position sensor input and modifies fuel strategy based on these inputs.

When the key is in the ON position and the engine is not running (zero rpm). the Automatic Shutdown (ASD) relay and fuel pump relay are not energized.
- Therefore battery voltage is not supplied to the fuel pump, ignition coil, fuel injectors or oxygen sensor heating element.