Circuit Description
WARNING: This page is about a different car, the 2004 Saturn Ion Red Line, 2004 Saturn Ion 3, 2004 Saturn Ion 2, and 2004 Saturn Ion 1. However, it is still accessible from the selected car via links, so may be relevant.
By pulse width modulating (PWM) the Cruise Control Servo Move Signal circuit the engine control module (ECM) indicates to the cruise control module how much accelerator pedal movement is necessary. The amount of pedal movement is determined by the duty cycle of the PWM signal, which is sent every 100 ms. DTC 1580 sets when Cruise Control Servo Move Signal circuit is commanded high, PWM is ON, and the voltage level at the ECM is low.