Antilock General Description

These models use the three sensor Four Wheel Antilock (4WAL) system. Speed information is obtained using a Wheel Speed Sensor (WSS) at each front wheel and the Vehicle Speed Sensor (VSS) for rear wheel speed information. 4WAL reduces the occurrence of wheel lockup during severe brake applications. The system regulates hydraulic pressure to all four wheels. The pressure is regulated by the Brake Pressure Modulator Valve (BPMV) located inside the engine compartment on the left inner fender.

The BPMV is defined as the lower, hydraulic control portion of the antilock assembly. This component includes the internal control valves, electric motor and pumps. It does not include the Electronic Brake Control Module (EBCM) or combination valve.

The Electro-Hydraulic Control Unit (EHCU) is the entire unit, including the BPMV, Electronic Brake Control Module and combination valve. The EBCM is the electronic control portion of the antilock assembly. It mounts to the top of the BPMV and is housed in aluminum with a black plastic top.