General Description

GENERAL DESCRIPTION




The rear wheel antilock system (RWAL) is designed to reduce rear wheel lock-up during a severe brake application, thus maintaining rear end stability. The system functions by regulating the rear hydraulic brake line pressure. The pressure regulation is accomplished by an antilock valve which is located on the front right side of engine room. The antilock valve is made up of two valves, a dump valve which releases pressure into an accumulator and an isolation valve which maintains rear brake pressure. The valve is controlled by a microcomputer which is part of the Electronic Brake Control Module (EBCM).

The EBCM is mounted at the front of the center console. Under severe brake application, as pressure is applied to the brake pedal, the EBCM is designed to permit the valve to do one of three functions or a combination of all three. The EBCM will allow the valve to either maintain the same amount of hydraulic pressure, release hydraulic pressure through the dump valve into the accumulator or increase the pressure by pulsing the isolation valve.

The EBCM operates by receiving signals from the speed sensor (which is located in the differential carrier), combination valve and the brake light switch. The RWAL system is connected to the RWAL indicator light located on the dash. An indication of the RWAL operation and a bulb check is performed each time the ignition is turned "ON". The indicator light will remain on for about two seconds. A RWAL system malfunction is indicated if the RWAL indicator light stays on, or comes on during driving. To determine the specific trouble, refer to "Rear Wheel Antilock (RWAL) System Diagnostics". Testing and Inspection