Antilock Brake System (Abs) Module

DESCRIPTION 

Courtesy of CHRYSLER GROUP, LLC

1 - ABS Module

2 - HCU

The ABS module is a microcontroller-based device which monitors the ABS during normal braking and controls it when the vehicle is in an ABS stop or when in a traction control situation. The ABS module utilizes a 38-way electrical connector on the vehicle wiring harness. The power source for the ABS module is through the ignition switch in the RUN or ON position.

The ABS module is mounted to the Hydraulic Control Unit (HCU) as part of the Integrated Control Unit (ICU). The ICU is located in the engine compartment below the master cylinder on the front suspension cradle/crossmember. For information on the ICU. Refer to BRAKE SYSTEM, DESCRIPTION AND OPERATION .

Electric Parking Brake (EPB) control is managed by the ABS module.

OPERATION 

The primary functions of the Antilock Brake System (ABS) module are to:

• Monitor the antilock 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 to the wheel brakes while the system is in an ABS mode.
• Store diagnostic information.
• Provide communication to the scan tool while in diagnostic mode.
• Illuminate the amber ABS warning indicator lamp.
• Illuminate the ESC function lamp in the message center on the instrument panel when a traction control event occurs.
• Illuminate the ESC function lamp when the amber ABS warning indicator lamp illuminates.

The ABS module constantly monitors the antilock brake system for proper operation. If the ABS module detects a fault, it will turn on the amber ABS warning indicator lamp and disable the antilock braking system. The normal base braking system will remain operational.

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 coils to actuate. The coils then open and close the valves in the 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.

The ABS module contains a self-diagnostic program that monitors the antilock brake system for system faults. When a fault is detected, the amber ABS warning indicator lamp is turned on and the fault diagnostic trouble code (DTC) 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 ABS module memory even after the ignition has been turned off. The DTCs can be read and cleared from the ABS module memory by a technician using a scan tool. If not cleared with a scan tool, the fault occurrence and DTC will be automatically cleared from the ABS module 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.