Operation CHARM: Car repair manuals for everyone.

Engine Warm-Up



This is an Open Loop mode. The following inputs are received by the engine controller:

- Coolant temperature

- Idle contact switch (closed throttle switch)

- Manifold absolute pressure

- Engine speed (distributor pick-up)

- Throttle body temperature sensor

- Throttle position

- Park/neutral switch (auto trans)

- A/C switch

- Battery voltage

- Vehicle distance (speed) sensor

The engine controller provides a ground path for the injectors to precisely control injector pulse width. This is done by switching the ground on and off. On 5.9L engines, the injectors are fired 4 times per engine revolution. The engine controller adjusts engine idle speed, throttle stop angle, and ignition timing.