Antilock Brakes - Jeep 1996 Grand Cherokee Service Manual

5 - 34 BRAKES
GENERAL INFORMATION
ABS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
DESCRIPTION AND OPERATION
ABS SYSTEM RELAYS . . . . . . . . . . . . . . . . . . . . 38
ABS WARNING LAMP . . . . . . . . . . . . . . . . . . . . 38
ABS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
ACCELERATION SWITCH . . . . . . . . . . . . . . . . . 37
COMBINATION VALVE . . . . . . . . . . . . . . . . . . . . 37
CONTROLLER ANTILOCK BRAKES (CAB) . . . . . 35
HYDRAULIC CONTROL UNIT (HCU) . . . . . . . . . 35
WHEEL SPEED SENSORS AND TONE WHEEL . 37
DIAGNOSIS AND TESTING
ABS BRAKE SYSTEM . . . . . . . . . . . . . . . . . . . . 38
GENERAL INFORMATION
ABS
The antilock brake system (ABS) is an electroni-
cally operated, all wheel brake control system.
The system is designed to prevent wheel lockup
and maintain steering control during periods of high
wheel slip when braking. Preventing lockup is accom-
plished by modulating fluid pressure to the wheel
brake units.
The hydraulic system is a three channel design.
The front wheel brakes are controlled individually
and the rear wheel brakes in tandem (Fig. 1). The
ABS electrical system is separate from other electri-
cal circuits in the vehicle. A specially programmed
controller antilock brake unit (CAB) operates the sys-
tem components.
ABS system major components include:
• Controller Antilock Brakes (CAB)
• Hydraulic Control Unit (HCU)
• Wheel Speed Sensors (WSS)
• Acceleration Switch
• Main Relay And Pump Motor Relay
• ABS Warning Light
• Pump Motor Sensor
DESCRIPTION AND OPERATION
ABS
Battery voltage is supplied to the CAB ignition ter-
minal when the ignition switch is turned to Run posi-
tion. The CAB performs a system initialization
procedure at this point. Initialization consists of a

ANTILOCK BRAKES

INDEX
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SERVICE PROCEDURES
BLEEDING ABS BRAKE SYSTEM . . . . . . . . . . . 38
REMOVAL AND INSTALLATION
ACCELERATION SWITCH . . . . . . . . . . . . . . . . . 42
CONTROLLER ANTILOCK BRAKES . . . . . . . . . . 38
FRONT WHEEL SPEED SENSOR . . . . . . . . . . . 41
HYDRAULIC CONTROLLER UNIT . . . . . . . . . . . 39
REAR WHEEL SPEED SENSOR . . . . . . . . . . . . 42
SPECIFICATIONS
TORQUE CHART . . . . . . . . . . . . . . . . . . . . . . . . 43
static and dynamic self check of system electrical
components.
The static check occurs after the ignition switch is
turned to Run position. The dynamic check occurs
when vehicle road speed reaches approximately 10
kph (6 mph). During the dynamic check, the CAB
briefly cycles the pump and solenoids to verify oper-
ation.
If an ABS component exhibits a fault during ini-
tialization, the CAB illuminates the amber warning
Fig. 1 Jeep ABS System
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