GM Service Manual Online
For 1990-2009 cars only

Cruise Control System Description WO/ETC

Cruise control is a speed control system that maintains a desired vehicle speed under normal driving conditions. However, steep grades up or down may cause variations in the selected speeds. The electronic cruise control system has the capability to CRUISE, COAST, RESUME SPEED, ACCELERATE, and TAP-UP or TAP-DOWN.

With cruise control you can maintain a speed of about 40 km/h (25 mph) or more without keeping your foot on the accelerator. When the driver applies the brakes, presses the clutch pedal or turns off the on/off switch, the cruise control turns off.

The main parts of the cruise control system are the cruise control module assembly, the function control switches, the vehicle speed sensor (VSS), the cruise control release (brake) switch assembly, the cruise control (clutch) switch assembly and the stoplamp switch assembly.

The cruise control system uses a cruise control module assembly to obtain the desired vehicle cruise speed and operation. The cruise control module assembly has an electronic controller, and an electric stepper motor to vary the throttle in each different cruise control mode. Two important components in the module assembly help do this. The first is the electronic controller and the second is an electric stepper motor. The stepper motor operates in response to the electronic controller to maintain the desired cruise speed. The electric controller monitors vehicle speed and operates the electric stepper motor. The stepper motor operates in response to the electronic controller, to maintain the desired cruise speed. The electric stepper motor moves a strap that is attached to the cruise control cable which moves the throttle linkage. The cruise control module assembly contains a low speed limit which will prevent system engagement below a speed of 40 km/h (25 mph). The module assembly is not serviceable.

The operation of the electronic controller is controlled by function control switches located on the multi-function turn signal lever.

The cruise control function switch includes the ON/OFF, SET/COAST and R/A (resume/accelerate) switches. The switch assembly provides driver control of the cruise control system.

The cruise control release (brake) switch, the cruise control (clutch) switch and the stoplamp switch assemblies are used to disengage the cruise control. The cruise control release (brake) switch assembly and the stoplamp switch assembly, mounted on the brake pedal bracket, disengage the system electrically when the driver presses the brake pedal. The cruise control (clutch) switch, mounted on the clutch pedal bracket, will also disengage the system when the driver presses the clutch pedal. When either pedal is pressed, the speed of the vehicle is stored in the cruise module memory.

The Vehicle Speed Sensor (VSS) is mounted to the automatic or manual transaxle assembly and produces an AC signal. The frequency of this signal is proportional to the speed at which the automatic or manual transaxle assembly output shaft rotates, which in turn is proportional to the speed of the vehicle. The AC signal is supplied to the Powertrain Control Module (PCM) where it is converted to the number of pulses per mile per second to determine vehicle speed. The signal is then sent to the cruise control module assembly and the speedometer assembly at a rate of 4000 pulses per mile.

With cruise control, you can maintain a speed of about 40km/h (25mph) or more without keeping your foot on the accelerator. when the driver turns OFF the ON/OFF switch, or the ignition switch, the cruise control turns off. The vehicle speed stored in the memory of the cruise control module, will be lost.

Cruise Control System Description W/ETC

Cruise control is a speed control system that maintains a desired vehicle speed under normal driving conditions. However, steep grades may cause variations in the selected speeds. The electronic cruise control system has the capability to CRUISE, COAST, RESUME SPEED, ACCELERATE, and TAP-UP or TAP-DOWN.

The main parts of the cruise control system are:

    • The Throttle Actuator Control (TAC) Module.
    • The function control switches.
    • The stoplamp switch assembly.
    • The cruise release switch assembly.
    • The clutch pedal position sensor (CPP) if equipped.

The cruise control system uses the TAC module to maintain the desired vehicle cruise speed and operation. The TAC and the powertrain control module (PCM) communicate together to vary the throttle opening in each different cruise control mode. The PCM monitors vehicle speed and operates the throttle actuator. The throttle actuator operates in response to the TAC module, to maintain the desired cruise speed. The throttle actuator motor moves the throttle blade. The PCM assembly contains a low speed limit which will prevent system engagement below a minimum speed of 40 km/h (25 mph). The TAC or PCM module assemblys are not serviceable.