Basic System Operation

When brakes are applied with normal to moderate pressure, brake fluid is routed from master cylinder through HCU unrestricted to wheels. During heavy breaking conditions, brake fluid pressure is modulated through HCU to each front wheel individually and to rear wheels through one channel.

During an ABS stop hydraulic pressure is controlled to all 3 circuits. ABS system can build or release pressure at each wheel front wheel or both rear wheels, depending on signal generated by wheel speed sensor. ABS is operational with vehicle speeds of 12 MPH or more.

Amber ABS warning light is controlled by CAB. CAB along with Hydraulic Control Unit (HCU), is located near air cleaner housing. CAB controls ABS warning light by grounding circuit.

When ignition is turned on (system initialization), ABS warning light is on until CAB completes its self tests. At 12 MPH, a dynamic check is performed. If any component exhibits a trouble condition during system initialization or dynamic check, CAB will illuminate ABS warning light.