Controller Anti-Lock Brake (CAB)

The CAB is located in engine compartment, next to Hydraulic Control Unit (HCU). See Figure . When CAB determines wheel(s) are about to spin or lock-up by input signal from each wheel speed sensor, it activates appropriate valve in HCU to increase or decrease hydraulic pressure to each wheel, resulting in a slight pulsation of brake pedal. ABS operation will be automatically turned off when vehicle speed is less than 5 MPH.

CAB detects wheel spin and lock-up tendencies, controls fluid pressure modulation during ABS operation and monitors ABS system operation. CAB contains a self-diagnostic system which stores a Diagnostic Trouble Code (DTC) if a system failure exists. For additional information on self-diagnostic system, see SELF-DIAGNOSTIC SYSTEM  under DIAGNOSIS & TESTING. CAB receives input signals from wheels speed sensors, brakelight switch, ABS main relay, pump/motor relay and ABS warning light voltage. CAB controls valves in HCU for fluid pressure operation, ABS main relay, pump/motor relay, BRAKE warning light, traction control warning light and traction control function light.

On models with LTCS, CAB has the ability to calculate brake pad temperature. If brakes are used frequently and brake pad temperature becomes excessive according to CAB programmed limits, CAB will turn off LTCS and turn on LTCS traction control warning (TRAC OFF) light. ABS operation will not be affected when LTCS is shut off and no DTC will be stored in CAB. Once brake pads are cooled off, CAB will turn off TRAC OFF warning light and LTCS operation will be restored.