Electronic Brake Control Module: Description and Operation

Controller Antilock Brake Location:

PURPOSE
The Controller Antilock Brakes (CAB) is a microprocessor based device which monitors the ABS system during normal braking and controls it when in an ABS stop. The CAB is mounted in the right front corner of the engine compartment using an integral mounting bracket to attach it to the inner fender. The CAB uses a 60 way electrical connector on the vehicle wiring harness. The power source for the CAB is through the ignition switch in the Run or ON position.

NOTE: The CAB is not on the Chrysler Collision Detection (CCD) bus.

THE PRIMARY FUNCTIONS OF THE CAB
- Detect wheel locking tendencies.
- Control fluid modulation to the brakes while in ABS mode.
- Monitor the system for proper operation.
- Provide communication to the DRB scan tool while in diagnostic mode.

The CAB Continuously Monitors - the speed of each wheel through the signals generated at the Wheel Speed Sensors to determine if any wheel is beginning to lock. When a wheel locking tendency is detected, the CAB commands the Hydraulic Control Unit (HCU) to modulate brake fluid pressure in some or all of the hydraulic circuits. The CAB continues to control pressure in individual hydraulic circuits until a locking tendency is no longer present.

The ABS System Is Constantly Monitored - by the CAB for proper operation. If the CAB detects a fault, it will turn on the Amber ABS Warning Lamp and disable the ABS braking system. The normal Non ABS braking system will remain operational.

The CAB Contains A Self-diagnostic Program - which will turn on the Amber ABS Warning Lamp when a ABS system fault is detected. Faults are then stored in a diagnostic program memory. There are multiple fault messages which may be stored in the CAB and displayed through the DRB scan tool. These fault messages will remain in the CAB memory even after the ignition has been turned off. The fault messages can be cleared by using the DRB scan tool, or they will be automatically cleared from the memory after a minimum of 3500 vehicle miles are accumulated.

CONTROLLER ANTILOCK BRAKE INPUTS
- Four wheel speed sensors.
- Stop lamp switch.
- Ignition switch.
- System relay voltage.
- Ground.
- Pump/Motor Relay Monitor.
- Diagnostics Communications.

CONTROLLER ANTILOCK BRAKE OUTPUTS
- Decay Solenoids.
- ABS warning lamp.
- System relay actuation.
- Diagnostic communication (Single line ISOK).
- Pump motor relay actuation.
- Brake Lamp (Low Fluid/Pressure).