Fuel Control: Notes
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2003 GMC Yukon XL, 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Suburban, and 2003 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The PCM, using input signals, determines adjustments to the air/fuel mixture to provide the optimum ratio for proper combustion under all operating conditions. Fuel control systems can operate in the open loop or closed loop mode.