Cruise Control Description and Operation 2.8L and 3.6L

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 On/Off cruise control switch.

The engine control module (ECM) monitors the signal circuits of the cruise control switches The ECM uses the cruise control switch signal circuit in order to determine when to capture and maintain the vehicle speed. The ECM monitors the vehicle speed sensor signal circuit in order to maintain the vehicle speed. The ECM uses the throttle actuator control (TAC) motor in order control the vehicle speed. For further information on the TAC system, refer to Throttle Actuator Control (TAC) System Description in Engine Controls - 2.8L or to Throttle Actuator Control (TAC) System Description in Engine Controls - 3.6L (LY7).

Ignition voltage is supplied to the cruise control switch from the 10-ampere STRG CTLS fuse via the ignition 1 voltage circuit. The cruise control switches are arranged in a resistive ladder, with each cruise control function switch having a different resistance value. The ECM 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 ECM detects a predetermined voltage signal on the cruise control switch signal circuit, indicating that the On/Off switch is active. Similarly, when the resume/accel button or the set/coast button are activated, the ECM detects the predetermined voltage signal on the cruise control switch signal circuit. To engage the cruise control system, turn the cruise control system ON by pressing the cruise On/Off button On and momentarily press the set/coast button. The ECM will confirm that the cruise control criteria has been met. The ECM will record the vehicle speed and sends a class 2 message to the instrument panel cluster in order to illuminate the cruise indicator. The set/coast button and the resume/accel button will remain inactive when the ECM has not received the predetermined voltage signal from the On/Off switch. 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/coast button and the resume/accel button. When the cruise control system is engaged, pressing and holding the set/coast button will allow the vehicle to decelerate from the current set vehicle speed without deactivating the cruise control system. When the set/coast button is released, the ECM will record the vehicle speed and maintain the vehicle speed as the new set vehicle speed. When the cruise control system is engaged, momentarily pressing the set/coast button will allow the vehicle to decelerate at 1.6 km/h (1 mph) increments for each time that the set/coast button is momentarily pressed, with a minimum vehicle speed of 37 km/h (23 mph). Activating and holding the resume/accel button, 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 resume/accel button is released, the ECM will record the vehicle speed and maintain the vehicle speed as the new set vehicle speed. When the cruise control system is engaged, momentarily activating the resume/accel button will allow the vehicle to accelerate at 1.6 km/h (1 mph) increments for each time that the resume/accel button is momentarily activated, with the maximum acceleration total of 16 km/h (10 mph) over the current set vehicle speed . Momentarily activating the resume/accel button, after the cruise control system has been disengaged by pressing the brake pedal, will recall the previous set vehicle speed that is recorded in the ECM.

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

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 electronic brake control module (EBCM) monitors the brake pedal position sensor via the brake pedal position sensor signal circuit. The ECM receives a class 2 serial data message and detects a high voltage signal on stop lamp switch signal circuit from the EBCM indicating that the brake pedal has been pressed. For further information on the brake pedal position sensor, refer to Exterior Lighting Systems Description and Operation and to Brake Pedal Position Sensor Calibration in Lighting Systems. When the clutch pedal is applied, the normally closed CCP switch opens and the ECM detects a low signal voltage on the CCP switch signal circuit. The vehicle speed stored in the memory of the ECM will be erased when the cruise control On/Off button is pressed, 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 is disengaged, the ECM sends a class 2 message to the instrument panel cluster (IPC) in order to deactivate the cruise indicator.

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

Cruise Control Description and Operation 5.7L

Cruise control is a speed control system that maintains a desired vehicle speed under normal driving conditions at vehicle 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 throttle actuator control (TAC) module monitors the signal circuits of the following cruise control switches:

The powertrain control module (PCM) will engage and adjust vehicle speed based on the information received from the TAC module via the UART serial data link. For further information on the TAC system, refer to Throttle Actuator Control (TAC) System Description in Engine Controls - 5.7L.

The cruise control switches are located on the steering wheel.

Ignition voltage is supplied to the cruise control switch from the 10-ampere STRG CTLS fuse via the ignition 1 voltage circuit. When the normally open cruise control on/off switch is turned ON, the switch closes and the amber switch indicator illuminates. The TAC module detects a high signal voltage on the cruise control on switch signal circuit indicating that the on/off switch is active. When the normally open "-" switch is pressed, the switch closes and the TAC module detects a high signal voltage on the cruise control set/coast switch signal circuit. To engage the cruise control system, turn the on/off switch ON and momentarily press the "-" switch. The TAC module sends a UART serial data message to the PCM, in order to confirm that the cruise control enable criteria has been met. The TAC module will engage the cruise control system and record the selected vehicle speed. The PCM sends a class 2 message to the instrument panel cluster in order to illuminate the cruise control 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 "-" switch and the "+" switch. When the cruise control system is engaged, pressing and holding the "-" switch will allow the vehicle to decelerate from the current set vehicle speed without deactivating the cruise control system. When the "-" switch is released, the TAC module will record the vehicle speed and maintain the vehicle speed as the new set vehicle speed. When the cruise control system is engaged, momentarily pressing the "-" switch will allow the vehicle to decelerate at 1.6 km/h (1 mph) increments for each time that the "-" is momentarily pressed, with a minimum vehicle speed of 37 km/h (23 mph). When the normally open "+" switch is activated, the switch closes and the TAC module detects a high signal voltage on the cruise control resume/accel switch signal circuit. Activating and holding the "+" 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 "+" switch is released, the TAC module will record the vehicle speed and maintain the vehicle speed as the new set vehicle speed. When the cruise control system is engaged, momentarily activating the "+" switch will allow the vehicle to accelerate at 1.6 km/h (1 mph) increments for each time that the "+" switch is momentarily activated, with the maximum acceleration total of 16 km/h (10 mph) over the current set vehicle speed . Momentarily activating the "+" switch, after the cruise control system has been disengaged by pressing the brake pedal or the clutch pedal will recall the previous set vehicle speed that is recorded in the TAC module.

The powertrain control module (PCM) or the throttle actuator control (TAC) module disengages the cruise control operation based on the signals from the following switches:

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 electronic brake control module (EBCM) monitors the BPP sensor via the brake pedal position sensor signal circuit. When the brake pedal is pressed, the PCM receives a class 2 serial data message from the EBCM indicating the status or the stop lamps. The PCM and the TAC module also detects a high voltage signal on the BAS relay coil supply voltage circuit from the EBCM. For further information on the brake pedal position sensor, refer to Exterior Lighting Systems Description and Operation and to Brake Pedal Position Sensor Calibration in Lighting Systems. When the clutch pedal is applied, the normally closed CCP switch opens and the PCM detects a low signal voltage on the CCP switch signal circuit. The vehicle speed stored in the memory of the TAC module will be erased when the cruise control on/off button is turned OFF, or the ignition switch is turned OFF.

The cruise control system will disengage when the PCM detects that a driver override function has been active for approximately 60 seconds.

When the cruise control system is disengaged, the PCM sends a class 2 message to the instrument panel cluster (IPC) in order to deactivate the cruise indicator.

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