GM Service Manual Online
For 1990-2009 cars only

Perform the following procedure in order to test the operating modes of the cruise control system:

Steps 2-8 and Step 11 are used with both automatic and manual transmission models. Step 9 and Step 10 are for manual transmission models only.

  1. Ensure that all repair work has been completed on the cruise control system before beginning the cruise control functional check.
  2. Slide the Off-On-R/A switch to the ON position.
  3. In order to test the low speed lockout, perform the following steps:
  4. 3.1. Drive the vehicle at 32 km/h (20 mph).
    3.2. Depress the SET switch and release the switch.

    The cruise control must not engage.

  5. In order to test the set function, perform the following procedure:
  6. 4.1. Drive the vehicle at a steady speed of 89 km/h (55 mph).
    4.2. Depress the SET switch completely and release the switch.

    The cruise control should maintain a speed of approximately 89 km/h (55 mph).

  7. In order to test the brake release, perform the following procedure:
  8. 5.1. Depress the brake pedal.

    The cruise control must release the throttle, allowing the vehicle speed to drop.

    5.2. The system must not re-engage when the brake is released.
  9. In order to test the resume function, perform the following procedure:
  10. 6.1. With the vehicle speed at approximately 72 km/h (45 mph), slide the Off-On-R/A switch momentarily (less than 1 second) to the R/A position.
    6.2. The vehicle should accelerate to approximately 89 km/h (55 mph).
  11. In order to inspect the coast function, perform the following procedure:
  12. 7.1. Depress the SET switch and hold the SET switch.
    7.2. Allow the vehicle speed to drop to 80 km/h (50 mph).
    7.3. Release the switch.
    7.4. The cruise control should maintain the vehicle speed at approximately 80 km/h (50 mph).
  13. In order to inspect the accelerate function, perform the following procedure:
  14. 8.1. Slide the Off-On-R/A switch to the R/A position and hold the Off-On-R/A switch.

    The vehicle speed should begin to increase.

    8.2. Allow the vehicle to increase to 89 km/h (55 mph).
    8.3. Release the switch.
    8.4. The cruise control should maintain the vehicle speed at approximately 89 km/h (55 mph).
  15. In order to inspect the clutch release, perform the following procedure:
  16. 9.1. Depress the clutch pedal.

    The cruise control must release the throttle, allowing the vehicle speed to decrease.

    9.2. The system must not re-engage when the clutch pedal is released.
  17. In order to inspect the resume function, perform the following procedure:
  18. 10.1. With the vehicle speed at approximately 72 km/h (45 mph), slide the Off-On-R/A switch momentarily (less than 1 second) to the R/A position.
    10.2. The vehicle should accelerate to approximately 89 km/h (55 mph).
    10.3. Slide the Off-On-R/A switch to the OFF position.

    The cruise control system should disengage.

  19. If the cruise control function check proves OK, refer to Symptoms .