Grand Cherokee 2WD V8-4.7L VIN J (2004)
Electronic Brake Control Module: Description and Operation
CONTROLLER ANTILOCK BRAKE (CAB)
The antilock brake controller (CAB) is a microprocessor-based device that monitors wheel speeds and controls the antilock functions.
The primary functions of the CAB are:
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monitor wheel speeds
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detect wheel locking tendencies
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control fluid pressure modulations to the brakes during antilock stop operation
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control the ABS warning indicator
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monitor the system for proper operation
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provide communication to the DRBIII while in diagnostic mode store diagnostic information in non-volatile memory
The CAB continuously monitors the speed of each wheel. When a wheel locking tendency is detected, the CAB will command the appropriate HCU
valve to modulate brake fluid pressure to that wheel. Brake pedal position is maintained during an antilock stop by being a closed system with the use
of 3 accumulators. The CAB continues to control pressure in individual hydraulic circuits until a wheel locking tendency is no longer present. The
CAB turns on the pump/motor during an antilock stop.
The antilock brake system is constantly monitored by the CAB for the proper operation. If the CAB detects a system malfunction, it can disable the
antilock system and activate the ABS warning indicator. If the antilock function is disabled, the system will revert to standard base brake system
operation.
The CAB inputs include the following:
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four wheel speed sensors
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brake lamp switch
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ignition switch
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battery voltage
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diagnostic communication (PCI BUS)
The CAB outputs include the following:
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six valve/solenoid drivers
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pump/motor actuation
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ABS warning indicator actuation
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red brake warning indicator actuation
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diagnostic communication (PCI BUS)
