Antilock Brakes / Traction Control Systems: Description and Operation

The rear wheel anti-lock (RWAL) system continuously monitors rear wheel rotation during braking and corrects rear brake pressure to prevent full rear wheel lockup and provides more rear end stability. The system functions by regulating the rear hydraulic brake line pressure. The pressure regulation is accomplished by an anti-lock valve which is located on the right side frame rail. The anti-lock 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 Control Module (ECM).