GM Service Manual Online
For 1990-2009 cars only

Cruise control is a speed control system that maintains a desired vehicle speed under normal driving conditions. Steep grades may cause variations in the selected vehicle speeds.

The following are the main components of the Cruise Control System:

    • The stop lamp switch.
    • The steering column control module.
    • The cruise control switches.
    • The engine control module (ECM).
    • The vehicle speed sensor (VSS).

Cruise Control Engaged

The Cruise Control System will engage and adjust vehicle speeds, based on the activation of the following cruise control switches, which are located in the cruise control lever.

    • On/Off cancel switch
    • RES/ACCEL switch.
    • SET/DECEL switch.

steering column control module reads in the position of the cruise control switch and sends it by HS CAN to the ECM. Steering column control module is located at the steering column behind the steering wheel. It contains among other systems the ignition lock and the turn indicator and wiper function switch. It contains the following subsystems (some are options): Immobiliser, Steering wheel controls, Transponder antenna, Ignition Lock, Turn indicator switch, Low/ High beam switch, Cruise control switch, Info- display switch, Wiper switch, Receiver antenna for remote controlled central door locking, Steering angle sensor, Horn switch.

Cruise Control Disengaged

The engine control module (ECM) disengages the cruise control operation based on the signals from the following switches:

    • The stop lamp switch.
    • The cruise control On/Off switch.

The steering column control module determines when the cruise control cancel switch is activated. When the normally open cancel switch is closed, the steering column control module detects the predetermined voltage signal on the cruise control function switch circuit. The steering column control module sends a serial data message to the ECM in order to disengage the cruise control system.

The stop lamp switch is mounted on the brake pedal bracket. When the brake pedal is applied, the normally open stop lamp switch closes. The ECM monitors the stop lamp signal circuit through a discrete input and a serial data message signal from the steering column control module indicating the brake status. When both signals indicate the brake pedal is applied, the ECM will disengage the cruise control system.

The Cruise Control System will disengage when the cruise control On/Off switch is switched OFF. The vehicle speed stored in the memory of the engine control module will be erased when the cruise control On/Off switch is turned OFF, or the ignition switch is turned OFF.

The Cruise Control System will disengage when the ECM detects that a driver override function has been active for approximately 60 seconds. When the Cruise Control System has been disengaged, the ECM sends a serial message to the steering column control module in order to turn OFF the Cruise Engaged indicator, and to the driver information center (DIC) in order to turn OFF the CRUISE SET TO ### message.

Cruise Control Inhibited

The engine control module (ECM) inhibits the cruise control operation when any of the following conditions exist:

    • A Cruise Control System DTC has been set.
    • The vehicle speed is less than 38 km/h.
    • The vehicle speed is too high.
    • The vehicle is in PARK, REVERSE, NEUTRAL, or 1st gear.
    • The engine RPM is too low.
    • The engine RPM is too high.
    • The system voltage is not between 9-16 volts.
    • The Antilock Brake System (ABS)/Traction Control System (TCS) is active for more than 2 seconds.