Functional Description - Brake System Control Module (BSCM)

The BCM receives the Steering Angle Sensor (SAS) data from the Electric Power Steering (EPS) module in the steering gear and broadcasts the data on the Controller Area Network - Flex-Data (CAN-FD) data bus for BSCM calculations. The BCM gates all LIN data from the HDC, HOLD and ESC/TCS switches to the BSCM.

BRAKE SYSTEM CONTROL MODULE (BSCM)

The main functions of the BSCM are to:

Monitor the brake system for proper operation
Detect wheel locking or wheel slipping tendencies by monitoring the speed of all four wheels of the vehicle
Control fluid modulation while the system is in a slip mitigation event
Store diagnostic information
Provide communication to the diagnostic scan tool while in diagnostic mode
Illuminate the ABS indicator lamp, ESP indicator lamp, Red Brake Warning indicator lamp or the Malfunction Indicator Lamp (MIL)
Illuminate the ESC function lamp when a vehicle dynamic event is occurring
Provide vehicle speed information, by monitoring the wheel speed sensors, to all modules on the CAN bus
Control the EPB system
Monitor brake pressure in the hydraulic system by comparing the ABS Brake Pressure Sensor (Brake Booster Pressure) data and the Brake Pedal Pressure (Brake Pedal Pressure) sensor data in order to determine if the brake lights need to be activated (both pressure sensors are internal to the EBB)
Monitor brake fluid temperature (the fluid temperature sensor is internal to the EBB)

The BSCM constantly monitors the brake system for proper operation. If the BSCM detects a fault, it will illuminate a warning indicator lamp and disable some functions. The base braking system will remain operational.

NOTE: TCS is standard equipment on all models. With TCS, the ESC function lamp will illuminate anytime the ABS warning indicator lamp illuminates.

The BSCM continuously monitors the speed of each wheel through the signals generated by the wheel speed sensors to determine if any wheel is beginning to lock. When a wheel locking tendency is detected, the BSCM commands the coils to actuate. The coils then open and close the valves that modulate brake fluid pressure in some or all of the hydraulic circuits. The BSCM continues to control pressure in individual hydraulic circuits until a locking tendency is no longer present. The BSCM contains a self-diagnostic program that monitors the antilock brake system for system faults. When a fault is detected, a warning indicator lamp is turned on and a Diagnostic Trouble Code (DTC) fault is then stored in a diagnostic program memory. A latched fault will disable certain system functionality for the current ignition cycle. An unlatched fault will disable certain system functionality until the fault condition disappears. These DTCs will remain in the BSCM memory even after the ignition has been turned OFF. The DTCs can be read and cleared from the BSCM memory by a technician using a diagnostic scan tool. If not cleared with a diagnostic scan tool, the fault occurrence and DTC will be automatically cleared from the BSCM memory after the identical fault has not been seen during the next 3, 500 miles. Drive-off may be required for the amber ABS warning indicator lamp to go out on the next ignition cycle.

The BSCM works in conjunction with multiple subsystems including, APB, BAS, Drag Torque Control, EBD, EPB, ERM, ESC, HDC, HSA, ORA ESC, Rain Brake Support, Ready Alert Braking, TCS, TSC and YMC. All of these systems work together to enhance vehicle stability and control in various driving conditions.

The BSCM receives acceleration and yaw data from the ORC for use in making ESC system calculations.

The BSCM is powered by two 50 amp fuses in the Power Distribution Center (PDC). The BSCM receives an ignition RUN/START feed from a 10 amp fuse in the PDC.