Module, Anti-Lock Brake System (Abs): Operation

WARNING: This page is about a different car, the 2021 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.

The primary functions of the Anti-lock Brake System (ABS) module are to:

Monitor the ABS and Electronic Stability Program (ESP) for proper operation.
Detect wheel locking or wheel slipping tendencies by monitoring the speed of all four wheels of the vehicle.
Control fluid modulation to the brakes while the system is in ABS or Traction Control System (TCS) mode.
Modulates fluid pressure to the brakes to control vehicle yaw rate in ESP mode.
Store diagnostic information.
Provide communication to the scan tool while in diagnostic mode.
Illuminate the amber TCS/ESP indicator in the instrument cluster.

The ABS module constantly monitors the ABS and ESP (if equipped) for proper operation. If the ABS module detects a fault, it will turn on the amber TCS/ESP indicator and disable the ABS or ESP if so equipped. The normal base braking system will remain operational at that time.

The ABS module 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 ABS module commands the solenoid coils to actuate. The coils then open and close the valves in the Hydraulic Control Unit (HCU) that modulate brake fluid pressure in some or all of the hydraulic circuits. The ABS module continues to control pressure in individual hydraulic circuits until a locking tendency is no longer present.