Cruise Control Module: Description and Operation

Engine Controller - The engine controller controls the speed control system using information from several inputs. Throttle actuation when speed control is engaged is controlled by alternately grounding (at the engine controller) the vacuum and vent solenoids to add or subtract vacuum from the servo.

A most important sensor signal used by the engine controller for speed control is the vehicle distance sensor input. The controller determines vehicle speed using input from this sensor and is very sensitive to speed sensor problems.