GM Service Manual Online
For 1990-2009 cars only

The stepper motor cruise control (SMCC) is a speed control system which maintains a desired vehicle speed under normal driving conditions. However, steep grades may cause variations in the selected speeds. The system has the following settings:

    • CRUISE
    • COAST
    • RESUME SPEED
    • ACCELERATE
    • TAP-UP
    • TAP-DOWN

The cruise control module contains an electronic controller and an electric motor. The controller monitors the speed of the vehicle and operates the motor. In response, the motor moves a connecting strap that is attached to the cruise control cable. The cable moves the throttle linkage which varies the throttle position and maintains the desired cruise speed. The cruise control module contains a low speed limit which prevents engagement of the system below a minimum speed, approximately 25 mph.

The mode control switches are located on the multi-function turn signal lever. Cruise control is in Standby Disabled mode until all conditions which are inconsistent with cruise control operation are cleared.

With the ignition switch in RUN, battery voltage applies to terminal F of the cruise control module. When you move the slider switch to the ON position, battery voltage applies to terminal A of the cruise control module connector. If the driver of the vehicle does not depress the brake pedal, battery voltage is present at module terminal D. When the driver presses the brake pedal, battery voltage is present at module terminal G. Terminal G must see current flow through the center high mounted stoplamp bulbs in order for cruise to operate (disable) properly.

When the driver moves the slider switch to the R/A position, battery voltage applies to terminal C of the module. With the Set switch pressed, battery voltage is present at module terminal B.

Cruise control module connector terminal K is the speed signal terminal. In operation, voltage will oscillate between a high of 4 to 5 volts and low of near ground. Cruise Control Module terminal E is ground.

Terminal J signals the PCM when cruise control is engaged. The PCM determines the correct shift pattern for the transmission.

The PCM uses terminal H in order to inhibit cruise control when any of the following conditions, which are inconsistent with cruse operation, occur:

    • Vehicle speed is less than 25 mph
    • When the park/neutral position (PNP) switch indicates the following gears:
       - PARK
       - REVERSE
       - NEUTRAL
       - 1ST GEAR
    • When an under battery condition or an over battery condition exists
    • With low engine RPM
    • With high engine RPM (fuel cut-off)