Adaptive Cruise Control Components

WARNING: This page is about a different car, the 2020 GMC Terrain and 2020 Chevrolet Equinox. However, it is still accessible from the selected car via links, so may be relevant.

The adaptive cruise control functionality depends on various switches and control modules on the vehicle to function. Each component performs a function that is critical to the proper operation of the adaptive cruise control system. Adaptive cruise control will not operate if any single component has a fault. Communication between modules is via serial data. The following is a functional description of the B174W Frontview Camera - Windshield and the other associated components:

Frontview Camera - Windshield
K9 Body Control Module
K20 Engine Control Module
K17 Electronic Brake Control Module (if equipped)
K160 Brake System Control Module (if equipped)
P16 Instrument Cluster
Cruise Control Switch
Adaptive Cruise Control Gap Switch

B174W Frontview Camera - Windshield

The B174W Frontview Camera - Windshield analyzes data from various modules, sensors, and switches to provide enhanced safety features. In addition to enhanced safety features, the B174W Frontview Camera - Windshield provides the adaptive cruise control system functionality. The B174W Frontview Camera - Windshield utilizes it's own camera and internal logic to identify and classify objects in the road environment. The system scans the road environment to detect targets within its specified field of view. The B174W Frontview Camera - Windshield then sends throttle and/or brake commands to the K20 Engine Control Module and K17 Electronic Brake Control Module or K160 Brake System Control Module via serial data in order to control the vehicle acceleration/deceleration based on the data from the modules. The K20 Engine Control Module and K17 Electronic Brake Control Module or K160 Brake System Control Module provide throttle control and automatic braking needed for proper speed and braking adjustment. The following is a list of the B174W Frontview Camera - Windshield pertaining to the adaptive cruise control functionality:

Processes the road environment to get data concerning any vehicle ahead of the adaptive cruise control vehicle. Detection, parameter estimation, tracking, object classification and diagnostics are the primary functions. When an object is detected, the B174W Frontview Camera - Windshield calculates the object range, range rate, acceleration and azimuth angle parameters.
Performs adaptive cruise control distance control or speed control processing automatically. The adaptive cruise control operates in two possible states - cruise or follow. The normal operating state is cruise, whereby the vehicle speed is controlled to match the driver selected set speed. When a preceding vehicle is identified, the adaptive cruise control system will automatically transition into the follow speed state to provide proper lane spacing behind the target vehicle in front. The preceding vehicle's speed and acceleration, with the adaptive cruise control vehicle speed, acceleration and distance between the two vehicles will be used to determine the adaptive cruise control follow speed limit. The adaptive cruise control follow speed limit will ensure that an acceptable distance is maintained to the preceding vehicle.
Determines the follow speed limit for throttle control by the K20 Engine Control Module and arbitrates the brake and throttle control between the K17 Electronic Brake Control Module or K160 Brake System Control Module and the K20 Engine Control Module.
Requests brake light activation during automatic braking.
Provides operational feedback to the vehicle driver. The B174W Frontview Camera - Windshield sends signals for telltales and messages to be displayed on the P16 Instrument Cluster or driver information center.

K9 Body Control Module

The following are the adaptive cruise control System functions provided by the K9 Body Control Module:

Monitors all cruise control switches and the adaptive cruise control gap switch. The K9 Body Control Module relays the switch status to the B174W Frontview Camera - Windshield via serial data.
Illuminates the brake light based on a serial data message from the B174W Frontview Camera - Windshield during automatic braking.
Measures the brake pedal position and sends brake pedal travel status via serial data circuit to the K20 Engine Control Module. The K20 Engine Control Module disengages the adaptive cruise control system when the driver presses the brake pedal.

K20 Engine Control Module

The following are the adaptive cruise control system functions performed by the K20 Engine Control Module:

Provides the electronic throttle control to the adaptive cruise control System. The K20 Engine Control Module is also responsible for determining when a driver is overriding the adaptive cruise control throttle position by pressing the accelerator pedal.
Processes the cruise control switch requests received via serial data circuit from the K9 Body Control Module. Engaging and disengaging the adaptive cruise control system are functions performed by the K20 Engine Control Module.
Determines the driver selected vehicle speed. Unless the adaptive cruise control module requests a lower vehicle speed, the K20 Engine Control Module will control the vehicle speed to the driver selected set speed.
Allows automatic braking without disengaging the adaptive cruise control.

K17 Electronic Brake Control Module (if equipped)

The following are the adaptive cruise control System functions performed by the K17 Electronic Brake Control Module:

Provides automatic braking for the adaptive cruise control system. The B174W Frontview Camera - Windshield will request vehicle deceleration via serial data circuit.
Releases vehicle automatic braking when there is a throttle override by the driver pressing the accelerator.
Predicts brake temperatures. Excessive automatic braking may cause, the brake system may overheat. When the brakes are overheated, the K17 Electronic Brake Control Module requests the adaptive cruise control system to be temporarily disabled until the brakes cool to a normal operating temperature.

K160 Brake System Control Module (if equipped)

The following are the adaptive cruise control system functions performed by the K160 Brake System Control Module:

Provides automatic braking for the adaptive cruise control system. The B174W Frontview Camera - Windshield will request vehicle deceleration via serial data circuit.
Releases vehicle automatic braking when there is a throttle override by the driver pressing the accelerator.
Predicts brake temperatures. Excessive automatic braking may cause, the brake system may overheat. When the brakes are overheated, the K160 Brake System Control Module requests the adaptive cruise control system to be temporarily disabled until the brakes cool to a normal operating temperature.

P16 Instrument Cluster

The driver information center is a part of the P16 Instrument Cluster and displays the adaptive cruise control system warning messages. The B174W Frontview Camera - Windshield requests messages to be displayed on the driver information center by sending a serial data request. When the message is acknowledged by the driver and the cause of the message resolved, the driver information center turns the message off. The adaptive cruise control system will not operate if the driver information center has a fault.

Cruise Control Switch

The cruise control switch function is a common feature that is shared between the adaptive cruise control system and the regular cruise control system. The adaptive cruise control system will not operate if any cruise control switch fault exists. The cruise control switch is made up of the following cruise control function switches:

On/Off switch
Set/decrease switch
Resume/increase switch

The cruise control function switches are arranged in a resistor ladder design whereby each switch function is has a different resistance value. The K9 Body Control Module provides a constant voltage reference to the cruise control switches and monitors switch feedback from a specific signal circuit. When a button is pressed, the voltage monitored on the signal circuit changes based on the number of resistors in the resistor ladder. This K9 Body Control Module recognizes this voltage as a specific cruise control switch function. The associated cruise control function detected by the K9 Body Control Module is then sent to the K20 Engine Control Module as a serial data circuit message. On receiving the message, the K20 Engine Control Module provides the cruise control function requested by the K9 Body Control Module. The K20 Engine Control Module is responsible for recognizing and responding to cruise control switch requests sent by the K9 Body Control Module. The cruise control function switches are used by the K20 Engine Control Module to communicate to the B174W Frontview Camera - Windshield the driver selected vehicle speed. The driver selected vehicle speed is communicated through serial data circuit to the B174W Frontview Camera - Windshield and the K9 Body Control Module. The adaptive cruise control system engages and adjusts vehicle speeds based on the activation of the following cruise control function switches:

Adaptive Cruise Control Gap Switch

The gap switch allows the driver to determine how closely the adaptive cruise control vehicle follows a target vehicle while adaptive cruise control is engaged. When the adaptive cruise control vehicle speed is being limited due to a slower travelling vehicle, the adaptive cruise control vehicle speed is automatically controlled to the follow distance. The gap switch has three following distance selections that range from near to far. The distance maintained for a selected gap will vary based on vehicle speed: The faster the vehicle speed, the greater than gap. The gap setting can only be adjusted when the adaptive cruise control system is engaged.

The gap switch is a momentary switch located as part of the cruise control switch assembly. The gap switch is located in a resistor ladder. The K9 Body Control Module provides a constant voltage reference to the gap switch and monitors switch feedback from a specific signal circuit. When the gap switch button is pressed, the voltage monitored on the signal circuit changes based on the number of resistors in the resistor ladder. This K9 Body Control Module recognizes this voltage as the gap switch function. The gap switch is detected by the K9 Body Control Module and then sent to the K20 Engine Control Module and B174W Frontview Camera - Windshield as a serial data message. On receiving the message, the K20 Engine Control Module and B174W Frontview Camera - Windshield will adjust the following distance based on the driver selected setting.

The initial push of the gap switch recalls the current setting and activates the display. Subsequent pushes of the gap switch will change the gap setting.