Thought this was interesting. Looks like vehicle complexity is getting crazy. Brake System Overview Note: ZF TRW’s Integrated Brake Control is a 1-piece module that eliminates the master cylinder, vacuum pump and associated hoses while incorporating electronic stability control, traction control and an electric motor to push hydraulic fluid to brakes at all four corners. The module is 13 lbs. (6 kg) lighter than the total weight of a conventional system and only requires about half the packaging space underhood. The vehicles are equipped with a ZF TRW Integrated Brake Control (IBC), also known as a Brake System Control Module. The IBC is an electromechanical device that interprets and converts driver input and provides a corresponding hydraulic pressure output to activate a standard brake system according to driver demand. In an event of no electrical energy or failure condition the driver’s input is mechanically converted to a hydraulic pressure output. Use DOT 4 Hydraulic Brake Fluid (GM Part No. 19299570, in Canada 19299571). Electrical Component Operation The Body Control Module (BCM) monitors the brake pedal position sensor signal when the brake pedal is applied and sends a high speed serial data message to the Brake System Control Module indicating the brake pedal position. The following electrical components are used: Wheel Speed Sensors: Equipped with unique directional wheel speed sensors that can detect wheel direction as well as zero wheel speed. The wheel speed sensors are Active sensors that receive a 12 V power supply from the Brake System Control Module and returns an output signal to the module. As the wheel spins, the wheel speed sensor sends the Brake System Control Module a DC square wave signal. The Brake System Control Module uses the frequency of the square wave signal to calculate the wheel speed. Multi-Axis Acceleration Sensor: The yaw rate, lateral acceleration and longitudinal acceleration sensors are combined into one multi-axis acceleration sensor, internal to the inflatable restraint sensing and diagnostic module. The Brake System Control Module receives serial data message inputs from the three sensors and activates Stability Control and Hill Hold Start Assist functions depending on multi-axis acceleration sensor input. Multifunction Switch: The traction control switch is a multifunction momentary switch. The traction control and stability control are manually disabled or enabled by pressing the traction control switch. Steering Wheel Angle Sensor: The Brake System Control Module receives serial data message inputs from the steering angle sensor. The steering wheel angle sensor signal is used to calculate the intended driving direction. The sensor is an internal part of the power steering gear. Transmission Control Module: The Brake System Control Module receives high speed serial data message inputs from the transmission control module indicating the gear position of the transmission for Hill Start Assist and Hill Hold functions. Vehicle Brake Enhancement Systems Depending on options, the following vehicle brake enhancement systems are provided: Power-Up-Self Test: The Brake System Control Module performs the first phase of the power-up-self test when the ignition is first turned ON. This phase consists of internal testing of the Brake System Control Module and electrical tests of system sensors and circuits. Antilock Brake system : ABS provides the active control/modulation of brake fluid hydraulic pressure to the front and/or rear brake corner subsystems (brake torque control) to preclude wheel lock-up and enhance tire-to-road longitudinal braking traction. Avoidance of wheel lock-up provides the driver with the ability to maintain vehicle stability and steerability and minimizes vehicle stopping distance. Brake Assist: Brake Assist provides additional brake pressure over the pressure provided by the conventional brake apply system. Panic Brake Assist: Panic Brake Assist will apply the brakes more quickly when a panic brake situation is determined. Panic Brake Assist detects that the driver intent is to stop the vehicle as quickly as possible, but the driver does not apply sufficient brake pressure to do so. The feature will detect the driver intent then actively apply brake pressure to maximum pressure, activating the ABS system and stopping the vehicle as quickly as possible. Hydraulic Fade Compensation: Based on a brake disc/pad temperature estimate, driver applied master cylinder pressure and vehicle deceleration rate, Hydraulic Fade Compensation will increase brake system pressure above driver applied brake pressure when the brake system determines a gross fade condition. Rear Brake Boost: Rear Brake Boost provides rear hydraulic brake assist to ensure that all four corners are achieving maximum braking during ABS. When vehicle loading is heavily rear axle biased the rear brakes may not utilize all of the available road adhesion. Rear Brake Boost will provide additional pressure to the rear brakes when the front brakes ABS are activated and the rear wheels have low slip. Electronic Pre-Fill: Electronic Pre-Fill is used to reduce the brake response time when the driver quickly releases the accelerator pedal. This is also used to support the use of low drag calipers.