Cruise Control: Description and Operation

The speed control system is operated by means of five switches on the steering wheel. The functions are:







The speed control unit provides signals to the stepper motor housed in the actuator. The stepper motor moves the throttle body cam by means of an internal geartrain and a cable linkage. The vehicle speed sensor generates the reference signal that the control unit compares to the speed setting selected by the driver. If a discrepancy exists, the stepper motor will adjust the throttle body cam setting, correcting the vehicles speed.

Any of the switches operated by the brake or clutch pedal (vehicles fitted with manual transaxle) will interrupt the speed control operation by releasing the speed control actuator cable and returning the throttle body cam to the position set by the throttle pedal.







Speed Control Actuator
The speed control actuator is mounted on the left-hand inner fender behind the suspension unit top mount. The speed control actuator incorporates the following components:
- The electronic speed control unit.
- The stepper motor and geartrain, electromagnetic coupling and reduction gearing.







Speed Control Unit
The speed control unit evaluates incoming signals from the system sensors and switches. It actuates a stepper motor and cable linkage to adjust the throttle body cam, maintaining a constant vehicle road speed.

If the clutch pedal (vehicles with manual transaxle) or the brake pedal are depressed, the speed control unit interrupts the speed control operation.







Stepper Motor
When the speed control system is activated, the windings in the stepper motor are energized by the speed control actuator which makes sure accurate positioning of the throttle body cam The vehicle road speed then settles to the speed selected by the driver.

Actuator Switches







When the ON switch is pressed the speed control system is activated. When the vehicle is travelling at a speed greater than 48 km/h (30 mph) the speed control actuator will accept speed inputs.







Pressing the SET/ACC switch at any speed in excess of 48 km/h (30 mph) causes the vehicle to accelerate or maintain the present speed. The switch can be used in three ways.
- Accelerate the vehicle with the accelerator pedal to the required speed, press and release the SET/ACC switch, the vehicle will then maintain the required speed.
- Press the SET/ACC switch and hold it down until the vehicle reaches the required speed. When released, the speed is stored in the memory and used to maintain the vehicle speed.
- Press the SET/ACC switch repeatedly in order to increase the road speed in steps of approximately 1.6 km/h (1 mph).







The COAST switch is used to reduce the vehicles road speed. The switch can be used in two ways:
- Press and hold the COAST switch down until the vehicle slows to the required speed. When the switch is released, the speed is stored in the memory and used to maintain the vehicle speed.
- Press the COAST switch repeatedly to reduce the vehicle road speed in steps of approximately 1.6 km/h (1 mph).







Press the RES switch to return the vehicle speed to the set speed after the speed control has been deactivated by the brake pedal. Pressing and releasing the RES switch at any speed greater than 48 km/h (30 mph) will return the vehicle speed to the previous set speed.







Pressing the OFF switch deactivates the speed control system. The speed setting stored in the speed control unit memory will be erased.







Brake Pedal Position (BPP) Switch
If the brake pedal is depressed while the speed control system is active, the speed control actuator receives a signal from the brake pedal position switch. This causes the speed control actuator to deactivate and close the throttle body cam.







Switch-Deactivator, Speed Control
If the brake pedal is depressed rapidly while the speed control system is active, the speed control actuator receives a signal from the speed control deactivator switch. This causes, the electromagnetic actuated coupling on the stepper motor to immediately disconnect the motor from the throttle body cam. This allows the cable and throttle body cam to close rapidly under throttle return spring control.







Clutch Pedal Position (CPP) Switch (with manual transaxle)
If the clutch pedal is depressed while the speed control system is active, the speed control actuator receives a signal from the clutch pedal position switch. This causes the speed control actuator to deactivate and close the throttle body cam.