Cruise control is a speed control system that maintains a desired vehicle speed under normal driving conditions at speeds above 40 km/h (25 mph). Steep grades may cause variations in the selected vehicle speeds.

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

The Cruise Control System will engage and adjust vehicle speeds, based on the activation of the following cruise control switches, which are located on the steering wheel:

The body control module (BCM) monitors the signal circuit of the cruise control switches. The BCM relays the cruise control switch status to the engine control module (ECM)/ powertrain control module (PCM) via the serial data circuit. The ECM/PCM uses the status of the cruise control switch to determine when to capture and maintain the vehicle speed. The ECM/PCM monitors the vehicle speed signal circuit in order to determine the desired vehicle speed. The throttle actuator control (TAC) motor is used to maintain the vehicle speed. For further information on the TAC System, refer to Throttle Actuator Control (TAC) System Description for the 3.8L engine or Throttle Actuator Control (TAC) System Description for the 4.6L engine.

Voltage is supplied to the cruise control switch through a reference voltage circuit supplied by the BCM. The cruise control switches are arranged in a resistive ladder design, with each cruise control function switch having a different resistance value. The BCM detects a specific voltage value that is associated with the cruise control function switch being activated. When the normally open cruise control On/Off switch is turned ON, the switch closes and the BCM supplies a ground to the cruise control switch ON indicator circuit and it becomes illuminated. The BCM sends a serial data message to the ECM/PCM indicating that the On/Off switch is active. Similarly, when the normally open + RES switch or the normally open - SET switch are pressed, the switch closes and the BCM detects the predetermined voltage signal on the - SET switch and the + RES switch signal circuit. The BCM sends a serial data message to the ECM/PCM indicating that the + RES switch or the - SET switch is active. To engage the Cruise Control System, ensure that the vehicle speed is above 40.2 km/h (25 mph), and then turn the On/Off switch ON and momentarily press the - SET switch. The ECM/PCM will engage the Cruise Control System and record the vehicle speed. The ECM/PCM sends a serial data message to the instrument panel cluster (IPC) in order to illuminate the Cruise Engaged indicator.

Pressing the accelerator pedal, while the Cruise Control System is engaged, will allow the driver to override the Cruise Control System in order to accelerate the vehicle beyond the current set vehicle speed. When the accelerator pedal is released, the vehicle will decelerate and resume the current set vehicle speed. The driver can also override the current set vehicle speed via the - SET switch and the + RES switch. With the Cruise Control System engaged, pressing and holding the - SET switch will allow the vehicle to decelerate from the current set vehicle speed without deactivating the Cruise Control System. When the - SET switch is released, the ECM/PCM will record the vehicle speed and maintain the vehicle speed as the new set vehicle speed. Momentarily pressing - SET switch will allow the vehicle to decelerate at 1.6 km/h (1 mph) increments for each time that the - SET switch is momentarily pressed, with a minimum vehicle speed of 37 km/h (23 mph). Pressing and holding the + RES switch, when the Cruise Control System is engaged, will allow the vehicle to accelerate to a greater vehicle speed than the current set vehicle speed. When the + RES switch is released, the ECM/PCM will record the vehicle speed and maintain the vehicle speed as the new set vehicle speed. Momentarily pressing the + RES switch will allow the vehicle to accelerate at 1.6 km/h (1 mph) increments for each time that the + RES switch is momentarily pressed, with the maximum acceleration total of 16 km/h (10 mph) over the current set vehicle speed.

If the Cruise Control System is disengaged by pressing the brake pedal or by activating the CANCEL switch, momentarily activating the + RES switch will recall the previous vehicle speed

The ECM/PCM will disengage cruise control operation based on the signals from the following switches:

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

The BPP sensor is mounted on the brake pedal bracket. Pressing the brake pedal while the cruise control is engaged will disengage the Cruise Control system. The BCM monitors the BPP sensor signal circuit as the voltage signal increases, while the pedal reaches the fully applied position. The BCM sends a serial data message to the ECM/PCM indicating the position of the brake pedal. For more information on the BPP sensor, refer to Exterior Lighting Systems Description and Operation .

The Cruise Control System will also disengage when one of the following conditions exist:

When the Cruise Control System has been disengaged, the ECM/PCM sends a serial data message to the instrument panel cluster (IPC) in order to turn OFF the Cruise Engaged indicator. The vehicle speed stored in the memory of the ECM/PCM will be erased when the cruise control On/Off switch is turned OFF, or the ignition switch is turned OFF.

Each time the Cruise Control System is disengaged, the ECM will keep track of the reason for system disengagement. The last 8 disengagement reasons will be recorded within the ECM memory, and can be viewed with a scan tool.

The ECM/PCM inhibits the cruise control operation when any of the following conditions exist: