Electronic Control Unit

The cruise control Electronic Control Unit (ECU) constantly monitors and compares set speed with actual vehicle speed from input sensors. When vehicle speed is greater than set speed, the ECU shortens the opening signal to the actuator, decreasing engine throttle valve opening and reducing vehicle speed.

When vehicle speed falls to less than set speed, the ECU lengthens the opening signal to the actuator. This increases engine throttle valve opening and increases vehicle speed.

The cruise control ECU has a self-diagnostic function. If the cruise control system is canceled by any condition other than driver operation, the ECU assumes a malfunction has occurred and may set a corresponding trouble code.