Buick Regal: Active Safety System Description and Operation

The active safety system is a comprehensive feature set designed to help a driver avoid collisions or reduce crash damage while driving, backing, and parking. The K124 Active Safety Control Module is the primary controller for the active safety system. The active safety control module communicates on multiple serial data busses to share information with various control modules throughout the vehicle.

The active safety control module uses various sensors and control modules to monitor the vehicle surroundings and take deliberate action to avoid collisions or reduce crash damage. The active safety system tightly integrates the forward collision alert, adaptive cruise control, parking assist, and active emergency braking systems into a single cohesive system.

The active safety control module communicates via serial data on the object detection bus with the B174W Frontview Camera - Windshield or K109 Frontview Camera Module, B233B Radar Sensor Module - Long Range, radar sensor module - short range left front, and radar sensor module - short range right front to create a virtual fusion image of the area in front of the vehicle. The active safety control module observes an actual visual image of the area directly ahead of the vehicle, within 60 m (197 ft), with the frontview camera. The radar sensor module - long range is used to measure the distance to objects that are up to 200 m (656 ft) in front the vehicle and the two radar sensor modules - short range are used to measure the distance to objects that are within 30 m (98 ft) of the front of the vehicle. Within 60 m (197 ft) of the vehicle, all of these inputs are combined to create a fusion image of the area in front of the vehicle. At up to 200 m (656 ft), the radar sensor module - long range will detect and begin tracking objects immediately in front of the vehicle. Within 60 m (197 ft), the frontview camera will confirm objects that have been detected by the radar sensor module - long range. The two radar sensor modules - short range improve cut-in detection, which are objects that enter the vehicle path from the side and are not necessarily detected by the frontview camera and radar sensor module - long range, who's focus are those object directly in front of the vehicle.

The fusion image created by the active safety control module is used to detect collision risks and take action based on the immediacy of the risk. The a collision risk exists, the active safety control module will alert the driver using the forward collision alert system. This will provide the driver with a visual and audible or haptic alert that a collision risk has been detected. If the driver does not take action to reduce the risk of collision, such as changing lanes or applying the brakes, the intelligent brake assist system will pre-fill the brake hydraulic system to reduce system response time and increase pressure when quickly applying the brakes. If a collision risk is imminent, the active safety control module will enter automatic collision preparation, which will automatically apply the brakes in an effort to mitigate the collision or reduce collision damage.

The active safety control module communicates with the steering wheel angle sensor and the multi-axis acceleration sensor via serial data on the chassis expansion bus. These sensors are used to determine the intended vehicle path. Using the steering data and vehicle acceleration data, the active safety control module will determine where the vehicle will be traveling and focus attention on objects in this path. An example would be a driver quickly changing lanes to avoid a collision. This would mitigate the collision risk in the previous lane and the active safety control module would quickly transition to tracking objects for any collision risk in the new lane based on intended vehicle path. The active safety control module also communicates with the electronic brake control module to instigate the braking functions of intelligent brake assist and automatic collision preparation.

At the rear of the vehicle, the active safety control module uses the radar sensor module - short range left rear, radar sensor module - short range right rear, and the parking assist control module as part of the backing warning system and the rear automatic braking system. Typical rear parking assist utilizes the parking assist control module and the four ultrasonic rear parking assist sensors to detect object when reversing at speed of up to 8 km/h (5 mph). The backing warning systems utilizes both the four ultrasonic rear parking assist sensors, as well as the radar sensor module - short range left rear and radar sensor module - short range right to detect object at speeds above 8 km/h (5 mph). The rear automatic braking system is intended to help avoid or reduce the harm caused by backing crashes or prevent the vehicle from being from being reversed into an object if the vehicle is already stopped.

The Active Safety System analyzes data from the various control modules and sensors listed below:

• K124 Active Safety Control Module
• B174W Frontview Camera - Windshield or K109 Frontview Camera Module
• B233B Radar Sensor Module - Long Range
• B233LF Radar Sensor Module - Short Range Left Front - If equipped
• B233RF Radar Sensor Module - Short Range Right Front - If equipped
• B233LR Radar Sensor Module - Short Range Left Rear - If equipped
• B233RR Radar Sensor Module - Short Range Right Rear - If equipped
• B233CR Radar Sensor Module - Short Range Rear Middle - If equipped
• K182 Parking Assist Control Module
• K17 Electronic Brake Control Module

Component Description

Active Safety Control Module

The active safety control module analyzes data from various modules, sensors, and switches to provide enhanced safety features. In addition to providing alerts, the active safety control module will provide driver assistance through integrated brake assist, automatic collision preparation, rear emergency braking, and adaptive cruise control. Inputs and outputs can either be connected directly to the active safety control module or communicate though serial data. The active safety control module communicates on a dedicated object detection bus, as well as the chassis expansion bus and low speed GMLAN.

Forward collision alert, lane departure warning, and park assist alerts can be user selected to either a haptic signal utilizing the driver's haptic signal motor seat or using beeps through the audio system. This setting can be found in the vehicle personalization menus. See the owner's manual for more detailed information on vehicle personalization.

If there is a DTC set in any of the modules that the active safety control module uses as inputs, it will send a "Service Driver Assist" to the instrument cluster to alert the driver of a problem with the system.

No other specific details are given unless the driver attempts to activate a specific system. For example if the driver attempts to turn on lane departure warning, the instrument cluster will display "Lane Departure Unavailable" and the indictor will flash and then go out. A scan tool must be used to read the DTCs that are causing the malfunction to help find the problem. Some of the inputs to the active safety control module can affect forward facing features, rear facing features, or all features. Systems to check to determine which area to focus are rear park assist for rear features, and lane departure warning and adaptive cruise control for front features. If none of the active safety system features are operative, there may be an issue with another module on the vehicle not providing the proper data to the active safety control module. If all active safety control module features are inoperative, check the Adaptive Cruise Control Inhibit History and Disengage History scan tool data for the reason for the malfunction.

Definitions of parameters and suggestions on what to look for can be found in K124 Active Safety Control Module: Scan Tool Information. Any item with a "Yes" was the reason why the adaptive cruise control system was inoperative at that time. In some cases verifying the module is the correct part number, has the latest version of software is necessary, and is calibrated properly.

• Active safety control module inputs:
  • Frontview Camera
  • Radar sensor module - long range
  • Radar sensor module - short range left front
  • Radar sensor module - short range right front
  • Radar sensor module - short range left rear
  • Radar sensor module - short range right rear
  • Parking assist control module
  • Multi-axis acceleration sensor
  • Steering wheel angle sensor
  • Wheel speed sensors
  • Forward collision alert switch
  • Lane departure warning switch
  • Parking assist switch
• Active safety control module outputs:
  • Body control module
  • Electronic brake control module
  • Engine control module
  • Instrument cluster
  • Head-up display
  • Memory seat module (safety alert seats)
  • Lane departure warning switch indicator
  • Parking assist switch indicator
  • Infotainment system

Frontview Camera

The frontview camera is located behind the windshield, looking out at the road ahead and detects lane markings and objects directly ahead, within a distance of approximately 60 meters (197 ft). The frontview camera is used for lane departure warning and forward collision alert systems. The frontview camera communicates with the active safety control module via serial data on the object detection bus.

Using information from the frontview camera, the active safety control module will provide forward collision alert and lane departure warning to the driver when appropriate. The alerts and warnings can be user-selected to be audible through the audio system or haptic using the active safety seat.

Radar Sensor Module - Long Range

The radar sensor module - long range is located behind the front grille emblem and is used in the 30 - 200 m (98 - 656 ft) range. The radar sensor module - long range communicates with the active safety control module via serial data on the object detection bus. In addition to the wiring harness ground, the module is grounded through the mounting bracket.

Radar Sensor Module - Short Range Front

There are two radar sensor module - short range front located behind the front fascia that detect objects up to approximately 30 meters (98 ft). The radar sensor modules - short range front communicate with the active safety control module via serial data on the object detection bus.

Radar Sensor Module - Short Range Rear

There are two radar sensor modules - short range rear located behind the rear fascia that detect objects up to approximately 30 meters (98 ft). The radar sensor modules - short range rear communicate with the active safety control module via serial data on the object detection bus.

Parking Assist Control Module

The parking assist control module uses ultrasonic object sensors located in the fascias to provide distance measurements to nearby objects. The park assist module sends rear object data to the active safety control module via serial data.

Electronic Brake Control Module

The electronic brake control module performs the braking activities of the active safety system. When requested by the active safety control module, the electronic brake control module will prepare or apply the brakes as necessary in response to an imminent collision.

Active Safety System Operation

Forward Collision Alert

The forward collision alert system is a convenience feature of the active safety control module, frontview camera, radar sensor module - long range, radar sensor module - short range left front, and radar sensor module - short range right front that issues a warning to the driver when a potential collision risk exists. When the system detects a vehicle in the path ahead, the green vehicle ahead indicator is illuminated on the instrument cluster. If the vehicle ahead is being followed too closely, the vehicle ahead indicator will be amber. When approaching another vehicle too rapidly, the collision alert symbol will flash in the head-up display. An audible alert sound will simultaneously sound or the safety alert seat will provide haptic feedback. The visual alert cannot be changed, but the driver can select between audible or haptic alerts in the vehicle personalization menus. Refer to the vehicle owner's manual for more detailed information on vehicle personalization.

Forward collision alert does not provide a warning to help avoid a crash, unless it detects a vehicle.

Forward collision alert may not detect a vehicle ahead if the frontview camera is blocked by dirt, snow, or ice, or if the windshield is damaged. It may also not detect a vehicle on winding or hilly roads, or in conditions that can limit visibility such as fog, rain, or snow, or if the headlamps or windshield are not cleaned or in proper condition. Keep the windshield, headlamps, and frontview camera area clean and in good repair.

Forward collision alert may provide unnecessary alerts for turning vehicles, vehicles in other lanes, objects that are not vehicles, or shadows. These alerts are normal operation and the vehicle does not need service.

Intelligent Brake Assist

Intelligent brake assist is designed to pre-fill the brake hydraulic system to reduce system response time and increase pressure when quickly applying the brakes. Using the active safety control module, frontview camera, radar sensor module - long range, radar sensor module - short range left front, and radar sensor module - short range right front, the system monitors the approach speed and distance to a vehicle ahead. If the Intelligent brake assist system determines a collision risk exists, it will begin preparations to the brake hydraulic system. When active, minor brake pedal pulsations or pedal movement may occur and this should be considered normal. Intelligent brake assist will resort to normal braking operation after an intelligent brake assist even has occurred when the brake pedal is released.

Automatic Collision Preparation

Automatic collision preparation system uses the active safety control module, frontview camera, radar sensor module - long range, radar sensor module - short range left front, and radar sensor module - short range right front to determine if an imminent collision risk exists. If the brakes have not been applied, the system will automatically apply the brakes in an effort to mitigate the collision or reduce collision damage. The system has a detection range of approximately 60 m (197 ft) and will only function when a vehicle is detected, as indicated by the green vehicle ahead indicator is illuminated on the instrument cluster.

Automatic collision preparation is not a substitute for normal vehicle braking and should not be relied on to brake the vehicle. Automatic collision preparation may not detect a vehicle ahead if the frontview camera is blocked by dirt, snow, or ice, or if the windshield is damaged. It may also not detect a vehicle on winding or hilly roads, or in conditions that can limit visibility such as fog, rain, or snow, or if the headlamps or windshield are not cleaned or in proper condition. Keep the windshield, headlamps, and frontview camera area clean and in good repair.

Backing Warning System

The backing warning system utilized the active safety control module, radar sensor module - short range left rear, radar sensor module - short range right rear, and the parking assist control module to warn of rear objects when backing up at speeds greater than 8 km/h (5 mph). Utilizing the ultrasonic rear object sensors, the parking assist control module can only detect object at seeps up to 8 km/h (5 mph). By utilizing the active safety control module and radar sensor modules - short range along with the parking assist control module and the rear object sensors, object can be detected at speeds greater than 8 km/h (5 mph).

While reversing at speeds greater than 8 km/h (5 mph), the backing warning system will alert the driver with an audible alert or through haptic feedback from the safety alert seat when an object is first detected. If the system detects a potential collision risk, a series of audible beeps or haptic feedback pulses will be provided, as well as a quick pulse of the brakes.

Rear Automatic Braking

The rear automatic braking system is designed to help avoid or reduce the harm caused by backing crashes. If the system detects the vehicle is backing too fast to avoid a collision, it may automatically brake hard to a stop.

Utilizing the active safety control module, radar sensor module - short range left rear, radar sensor module - short range right rear, and the parking assist control module, rear automatic braking attempts to avoid imminent collision by automatically braking the vehicle when traveling in reverse. In conjunction with the backing warning system, if the driver does not respond to the audible and haptic alerts while reversing, the system will automatically brake the vehicle to a stop.

Rear automatic braking also prevents the vehicle from backing into an object if the vehicle is stopped and shifted to R. If the system detects an object immediately behind the vehicle while attempting to reverse from a stop, the brakes will be applied.

Pressing the brake pedal after the vehicle comes to a stop will release the rear automatic braking. It may be necessary to release the electronic parking brake. When it is safe to do so, pressing the accelerator pedal firmly at any time will override the rear automatic braking. If rear automatic braking is active and there is no object behind the vehicle, make sure there is no snow, ice, or debris on the rear object sensors.

Lane Departure Warning/Lane Keep Assist

The lane departure warning system is a convenience feature that utilizes the frontview camera and active safety control module to determine if the vehicle has unintentionally crossed a lane marking and issue a warning. The frontview camera is located behind the windshield, looking out at the road ahead and detecting any lane markings. When the vehicle unintentionally leaves a detected lane, visual and audible or haptic alerts are given to the driver. The visual alert cannot be changed, but the driver can select between audible or haptic alerts in the vehicle personalization menus.

Refer to Lane Departure Warning Description and Operation for more information about the Lane Departure Warning function.

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