Cruise Control
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.
On models equipped with cruise control, the system is operated by the PCM. PCM receives inputs from Vehicle Speed Sensor (VSS), servo diaphragm position sensor, cruise control switch and brake release switch. Based on these inputs, PCM controls position of cruise control stepper motor. PCM prevents system engagement at speeds of less than 25 MPH. PCM is not serviceable; if defective, it must be replaced. A system fault is stored as a DTC in PCM memory.