Distance Sensing Cruise Control Module (DSCC): Notes

WARNING: This page is about a different car, the 2008 Cadillac XLR. However, it is still accessible from the selected car via links, so may be relevant.

The distance sensing cruise control module (DSCC) communicates with the forward looking sensor (FLS) via controller area network (CAN) serial data. The DSCC utilizes the FLS to identify and classify objects in the road environment. The FLS scans the road environment to detect targets within its specified field of view. The DSCC then makes throttle and/or brake commands to the engine control module (ECM) and electronic brake control module (EBCM) via GMLAN serial data circuit to control vehicle acceleration/deceleration based on data from the FLS radar. The ECM and EBCM provide throttle control and automatic braking needed for proper cruise speed adjustment. An internal yaw rate sensor is used by the DSCC to determine the predicted path of the adaptive cruise control (ACC) vehicle. The main power feed for the DSCC is the battery and this signal is always at battery potential. However, the ACC system only activates when the ignition 1 input is active and in the RUN position. The ignition 1 voltage signal to the DSCC has to be 9.2 volts or more to be considered active. When the ignition 1 signal is not active, all ACC functions are disabled. The following is a list of the DSCC functions:

The FLS radar processes the road environment to get data concerning any vehicle ahead of the ACC vehicle. Detection, parameter estimation, tracking, object classification and diagnostics are the primary FLS functions. When an object is detected, the DSCC calculates the object range, range rate, acceleration and azimuth angle parameters.
The DSCC performs ACC state processing automatically - distance control or speed control. The ACC system operates in 2 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 forward target is identified by the FLS, the ACC 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 ACC vehicle speed, acceleration and distance between the 2 vehicles will be used to determine the ACC follow speed limit. The ACC follow speed limit will ensure that an acceptable distance is maintained to the preceding vehicle.
The DSCC determines the Follow Speed limit for throttle control by the ECM.
The DSCC arbitrates the ACC system brake and throttle control between the EBCM and the ECM.
The DSCC requests brake light activation during automatic braking.
The DSCC provides operational feedback to the vehicle driver. The DSCC sends signals for telltales and messages to be displayed on the head-up display (HUD) or driver information center (DIC) via the body control module (BCM). The DSCC will provide audible feedback to the driver via the BCM and the radio amplifier as well.