Controller Anti-Lock Brake (CAB)

The CAB is located in engine compartment, on bottom of Hydraulic Control Unit (HCU). See Figure and 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 3-4 MPH.

CAB detects wheel spin and lock-up tendencies, controls fluid pressure modulation during ABS operation, and monitors ABS operation. CAB contains a self-diagnostic system which stores a diagnostic trouble code if a system failure exists. For additional information on self-diagnostic system, see SELF-DIAGNOSTIC SYSTEM OPERATION  . CAB receives input signals from wheels speed sensors, brakelight switch, ABS system relay, pump/motor relay, and ABS warning light voltage. CAB controls valves in HCU for fluid pressure operation, ABS system relay, pump/motor relay, traction control warning (TRAC OFF) light, and traction control function (TRAC ON) light.

On models with Traction Control System (TCS), CAB has the ability to calculate brake system overheating. If brakes are used frequently and brake pad temperature becomes excessive according to CAB programmed limits, CAB will turn off TCS and turn on TCS traction control warning (TRAC OFF) light for a preprogrammed time limit. Once brake system has cooled, CAB will turn off TRAC OFF warning light and TCS operation will be restored.