Cruise Control: Description and Operation

Cruise Control

How the Circuit Works

The throttle TP sensor/throttle actuator, located on the side of the throttle housing, is used to open and close the throttle plate for routine driving and cruise conditions.

Power Supply

With the ignition switch in ON (II) or START (III) and the cruise control main switch in ON, battery voltage is applied through fuse 9 (in the driver's under-dash fuse/relay box) to the CPU in the gauge assembly.

Fuse 47 is hot at all times and supplies battery voltage to the PCM when the brake pedal position switch is closed (brake pedal pressed).

Fuse 7 (in the auxiliary fuse box) is hot at all times and supplies battery voltage to the PCM when the throttle actuator control module relay is closed.

System Description

The PCM receives information signals about operating conditions from the multiplex control system, APP sensor, TP sensor/throttle actuator output shaft (countershaft) speed sensor and transmission range switch.

The PCM compares the actual speed of the vehicle to the selected speed, and then opens or closes the throttle as necessary to match the selected speed.

The brake pedal position switch releases the system's control of the throttle at the instant the brake pedal is pressed. The switch sends a signal to the PCM by applying power to the PCM on one circuit and removing power from the PCM on another circuit. The PCM responds by allowing the throttle to close.

The cruise control system will set and automatically maintain any speed above 25 mph (40 km/h).

When the SET switch is pressed at any speed above 25 mph (40km/h), the cruise control indicator in the gauge assembly illuminates. The cruise control system can be disabled by pressing the CANCEL switch, turning the cruise control main switch off or touching the brake pedal.

If the system is disengaged temporarily by the brake pedal position switch or transmission range switch, and the car's speed is still above 25 mph, pressing the RESUME switch will automatically return the vehicle to the previously set speed.

For gradual acceleration without pressing the accelerator pedal, press the RESUME switch and hold it there. To increase the speed in very small amounts, tap the RESUME switch one time for each one mph of increase.

To slow the car down, press the SET switch and hold it there. To decrease the speed in very small amounts, tap the SET switch one time for each one mph of decrease.